From 82aacde97fcffc8ea57157b96142ecfe388497e1 Mon Sep 17 00:00:00 2001 From: Christian Rinderknecht Date: Mon, 10 Feb 2020 19:07:20 +0100 Subject: [PATCH] More documentation rewrites. --- .../docs/advanced/entrypoints-contracts.md | 61 +- gitlab-pages/docs/advanced/first-contract.md | 48 +- .../docs/advanced/timestamps-addresses.md | 14 +- .../intro/src/what-and-why/ligo-counter.ligo | 35 +- .../intro/src/what-and-why/ligo-counter.mligo | 23 + .../src/what-and-why/ligo-counter.religo | 26 + gitlab-pages/docs/intro/what-and-why.md | 252 ++++++--- .../docs/language-basics/boolean-if-else.md | 17 +- .../docs/language-basics/functions.md | 93 ++-- gitlab-pages/docs/language-basics/loops.md | 76 +-- .../docs/language-basics/maps-records.md | 289 +++++++--- .../docs/language-basics/math-numbers-tez.md | 22 +- .../docs/language-basics/sets-lists-tuples.md | 526 +++++++++++++----- gitlab-pages/docs/language-basics/strings.md | 24 +- .../docs/language-basics/tezos-specific.md | 19 +- gitlab-pages/docs/language-basics/types.md | 114 +++- .../unit-option-pattern-matching.md | 26 +- .../variables-and-constants.md | 27 +- gitlab-pages/website/core/CodeExamples.js | 93 ++-- gitlab-pages/website/pages/en/index.js | 8 +- gitlab-pages/website/siteConfig.js | 13 +- .../version-next/contributors/origin.md | 4 +- .../version-next/contributors/philosophy.md | 11 +- .../version-next-sidebars.json | 22 +- src/passes/operators/operators.ml | 5 +- 25 files changed, 1238 insertions(+), 610 deletions(-) create mode 100644 gitlab-pages/docs/intro/src/what-and-why/ligo-counter.mligo create mode 100644 gitlab-pages/docs/intro/src/what-and-why/ligo-counter.religo diff --git a/gitlab-pages/docs/advanced/entrypoints-contracts.md b/gitlab-pages/docs/advanced/entrypoints-contracts.md index 29160031c..07bb7ee0c 100644 --- a/gitlab-pages/docs/advanced/entrypoints-contracts.md +++ b/gitlab-pages/docs/advanced/entrypoints-contracts.md @@ -1,20 +1,20 @@ --- id: entrypoints-contracts -title: Entrypoints to Contracts +title: Access function and Entrypoints --- -## Entrypoints +## Access Functions A LIGO contract is made of a series of constant and function declarations. Only functions having a special type can be called when -the contract is activated: they are called *entrypoints*. An -entrypoint need to take two parameters, the *contract parameter* and -the *on-chain storage*, and return a pair made of a *list of -operations* and a (new) storage. +the contract is activated: we called them *access functions*. An +access function takes two parameters, the *contract parameter* and the +*on-chain storage*, and returns a pair made of a *list of operations* +and a (new) storage. When the contract is originated, the initial value of the storage is -provided. When and entrypoint is later called, only the parameter is -provided, but the type of an entrypoint contains both. +provided. When an access function is later called, only the parameter +is provided, but the type of an access function contains both. The type of the contract parameter and the storage are up to the contract designer, but the type for list operations is not. The return @@ -23,7 +23,7 @@ has been defined elsewhere. (Note that you can use any type with any name for the storage.) - + ```pascaligo skip type storage is ... // Any name, any type type return is list (operation) * storage @@ -42,9 +42,9 @@ type return = (list (operation), storage); ``` -The contract storage can only be modified by activating an -entrypoint. It is important to understand what that means. What it -does *not* mean is that some global variable holding the storage is +The contract storage can only be modified by activating an access +function. It is important to understand what that means. What it does +*not* mean is that some global variable holding the storage is modified by the entrypoint. Instead, what it *does* mean is that, given the state of the storage *on-chain*, an entrypoint specifies how to create another state for it, depending on a parameter. @@ -54,7 +54,7 @@ is updated by the parameter. - + ```pascaligo group=a type storage is nat @@ -82,20 +82,29 @@ let main = ((parameter, store): (nat, storage)) : return => { ``` -In LIGO, the design pattern for entrypoints consists in actually -having exactly *one entrypoint*, like the `main` function in C. The -parameter of the contract is then a variant type, and, depending on -the constructors of that type, different functions in the contract are -called. In other terms, the unique entrypoint dispatches the control -flow depending on a *pattern matching* on the contract parameter. +## Entrypoints -In the following example, the storage contains a counter (of type -`nat`) and a name (of type `string`). Depending on the parameter of -the contract, either the counter or the name is updated. +In LIGO, the design pattern is to have *one* access function that +dispatches the control flow according to its parameter. Those +functions called for those actions are called *entrypoints*. + +As an analogy, in the C programming language, the `main` function is +the unique access function and any function called from it would be an +entrypoint. + +The parameter of the contract is then a variant type, and, depending +on the constructors of that type, different functions in the contract +are called. In other terms, the unique access function dispatches the +control flow depending on a *pattern matching* on the contract +parameter. + +In the following example, the storage contains a counter of type `nat` +and a name of type `string`. Depending on the parameter of the +contract, either the counter or the name is updated. - + ```pascaligo group=b type parameter is Entrypoint_A of nat @@ -188,7 +197,7 @@ any transaction that sends more tez than `0mutez`, that is, no incoming tokens are accepted. - + ```pascaligo group=c type parameter is unit type storage is unit @@ -232,7 +241,7 @@ let deny = ((param, store): (parameter, storage)) : return => { This example shows how `sender` or `source` can be used to deny access to an entrypoint. - + ```pascaligo group=c const owner : address = ("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx": address); @@ -287,7 +296,7 @@ counter contract. - + ```pascaligo skip // counter.ligo type parameter is diff --git a/gitlab-pages/docs/advanced/first-contract.md b/gitlab-pages/docs/advanced/first-contract.md index 19861291f..1e9c5f120 100644 --- a/gitlab-pages/docs/advanced/first-contract.md +++ b/gitlab-pages/docs/advanced/first-contract.md @@ -3,20 +3,24 @@ id: first-contract title: First contract --- -So far so good, we've learned enough of the LIGO language, we're confident enough to write out first smart contract. +So far so good, we have learned enough of the LIGO language, we are +confident enough to write out first smart contract. -We'll be implementing a counter contract, let's go. +We will be implementing a counter contract. -## Dry-running a contract +## Dry-running a Contract -Testing a contract can be quite easy if we utilize LIGO's built-in dry run feature. Dry-run works by simulating the entrypoint execution, as if it were deployed on a real chain. You need to provide the following: +Testing a contract can be quite easy if we utilize LIGO's built-in dry +run feature. Dry-run works by simulating the access function +execution, as if it were deployed on a real chain. You need to provide +the following: - `file` - contract to run - `entrypoint` - name of the function to execute -- `parameter` - parameter passed to the entrypoint (in a theoretical invocation operation) +- `parameter` - parameter passed to the access function (in a theoretical invocation operation) - `storage` - a mock storage value, as if it were stored on a real chain -Here's a full example: +Here is a full example: @@ -29,25 +33,29 @@ ligo dry-run src/basic.ligo main Unit Unit ``` -Output of the `dry-run` is the return value of our entrypoint function, we can see the operations emited - in our case an empty list, and the new storage value being returned - which in our case is still `Unit`. +Output of the `dry-run` is the return value of our access function, we +can see the operations emited - in our case an empty list, and the new +storage value being returned - which in our case is still `Unit`. -## Building a counter contract +## A Counter Contract -Our counter contract will store a single `int` as it's storage, and will accept an `action` variant in order to re-route our single `main` entrypoint into two entrypoints for `addition` and `subtraction`. +Our counter contract will store a single `int` as it's storage, and +will accept an `action` variant in order to re-route our single `main` +access function to two entrypoints for `addition` and `subtraction`. ``` type action is -| Increment of int + Increment of int | Decrement of int function main (const p : action ; const s : int) : (list(operation) * int) is - block {skip} with ((nil : list(operation)), - case p of + ((nil : list(operation)), + (case p of | Increment (n) -> s + n | Decrement (n) -> s - n - end) + end)) ``` @@ -98,11 +106,13 @@ ligo dry-run src/counter.ligo main "Increment(5)" 5 -Yay, our contract's storage has been successfuly incremented to `10`. +Our contract's storage has been successfuly incremented to `10`. ## Deploying and interacting with a contract on a live-chain -In order to deploy the counter contract to a real Tezos network, we'd have to compile it first, this can be done with the help of the `compile-contract` CLI command: +In order to deploy the counter contract to a real Tezos network, we'd +have to compile it first, this can be done with the help of the +`compile-contract` CLI command: @@ -156,7 +166,10 @@ Command above will output the following Michelson code: ``` -However in order to originate a Michelson contract on Tezos, we also need to provide the initial storage value, we can use `compile-storage` to compile the LIGO representation of the storage to Michelson. +However in order to originate a Michelson contract on Tezos, we also +need to provide the initial storage value, we can use +`compile-storage` to compile the LIGO representation of the storage to +Michelson. @@ -182,4 +195,5 @@ ligo compile-parameter src/counter.ligo main 'Increment(5)' -Now we can use `(Right 5)` which is a Michelson value, to invoke our contract - e.g. via `tezos-client` +Now we can use `(Right 5)` which is a Michelson value, to invoke our +contract - e.g. via `tezos-client` diff --git a/gitlab-pages/docs/advanced/timestamps-addresses.md b/gitlab-pages/docs/advanced/timestamps-addresses.md index 8c20da011..5174e1cc8 100644 --- a/gitlab-pages/docs/advanced/timestamps-addresses.md +++ b/gitlab-pages/docs/advanced/timestamps-addresses.md @@ -16,7 +16,7 @@ expression, please be aware that it is up to the baker to set the current timestamp value. - + ```pascaligo group=a const today : timestamp = now ``` @@ -44,7 +44,7 @@ constraints on your smart contracts. Consider the following scenarios. #### In 24 hours - + ```pascaligo group=b const today : timestamp = now const one_day : int = 86400 @@ -76,7 +76,7 @@ let one_day_later : timestamp = some_date + one_day; #### 24 hours Ago - + ```pascaligo group=c const today : timestamp = now const one_day : int = 86400 @@ -105,7 +105,7 @@ You can compare timestamps using the same comparison operators applying to numbers. - + ```pascaligo group=c const not_tommorow : bool = (now = in_24_hrs) ``` @@ -130,7 +130,7 @@ type `address`. Beware of failures if the address is invalid. Consider the following examples. - + ```pascaligo group=d const my_account : address = ("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx" : address) @@ -159,7 +159,7 @@ failure if the signature is invalid. Here is how you can define a signature: - + ```pascaligo group=e const my_sig : signature = ("edsigthTzJ8X7MPmNeEwybRAvdxS1pupqcM5Mk4uCuyZAe7uEk68YpuGDeViW8wSXMrCi5CwoNgqs8V2w8ayB5dMJzrYCHhD8C7" : @@ -188,7 +188,7 @@ failure if the key is invalid. Here is how you can define a key. - + ```pascaligo group=f const my_key : key = ("edpkuBknW28nW72KG6RoHtYW7p12T6GKc7nAbwYX5m8Wd9sDVC9yav" : key) diff --git a/gitlab-pages/docs/intro/src/what-and-why/ligo-counter.ligo b/gitlab-pages/docs/intro/src/what-and-why/ligo-counter.ligo index 989afba07..4fd886fb7 100644 --- a/gitlab-pages/docs/intro/src/what-and-why/ligo-counter.ligo +++ b/gitlab-pages/docs/intro/src/what-and-why/ligo-counter.ligo @@ -1,12 +1,25 @@ -type action is -| Increment of int -| Decrement of int -| Reset of unit +type storage is int -function main (const p : action ; const s : int) : (list(operation) * int) is - block { skip } with ((nil : list(operation)), - case p of - | Increment(n) -> s + n - | Decrement(n) -> s - n - | Reset(n) -> 0 - end) \ No newline at end of file +type parameter is + Increment of int +| Decrement of int +| Reset + +type return is list (operation) * storage + +(* Two entrypoints *) + +function add (const store : storage; const delta : int) : storage is store + delta + +function sub (const store : storage; const delta : int) : storage is store - delta + +(* Main access point that dispatches to the entrypoints according to + the smart contract parameter. *) + +function main (const action : parameter; const store : storage) : return is + ((nil : list (operation)), // No operations + case action of + Increment (n) -> add (store, n) + | Decrement (n) -> sub (store, n) + | Reset -> 0 + end) diff --git a/gitlab-pages/docs/intro/src/what-and-why/ligo-counter.mligo b/gitlab-pages/docs/intro/src/what-and-why/ligo-counter.mligo new file mode 100644 index 000000000..3cfa8551f --- /dev/null +++ b/gitlab-pages/docs/intro/src/what-and-why/ligo-counter.mligo @@ -0,0 +1,23 @@ +type storage = int + +type parameter = + Increment of int +| Decrement of int +| Reset + +type return = operation list * storage + +(* Two entrypoints *) + +let add (store, delta : storage * int) : storage = store + delta +let sub (store, delta : storage * int) : storage = store - delta + +(* Main access point that dispatches to the entrypoints according to + the smart contract parameter. *) + +let main (action, store : parameter * storage) : return = + ([] : operation list), // No operations + (match action with + Increment (n) -> add (store, n) + | Decrement (n) -> sub (store, n) + | Reset -> 0) diff --git a/gitlab-pages/docs/intro/src/what-and-why/ligo-counter.religo b/gitlab-pages/docs/intro/src/what-and-why/ligo-counter.religo new file mode 100644 index 000000000..74292563c --- /dev/null +++ b/gitlab-pages/docs/intro/src/what-and-why/ligo-counter.religo @@ -0,0 +1,26 @@ +type storage = int; + +type parameter = + Increment (int) +| Decrement (int) +| Reset; + +type return = (list (operation), storage); + +(* Two entrypoints *) + +let add = ((store, delta) : (storage, int)) : storage => store + delta; + +let sub = ((store, delta) : (storage, int)) : storage => store - delta; + +(* Main access point that dispatches to the entrypoints according to + the smart contract parameter. *) + +let main = ((action, store) : (parameter, storage)) : return => { + (([] : list (operation)), // No operations + (switch (action) { + | Increment (n) => add ((store, n)) + | Decrement (n) => sub ((store, n)) + | Reset => 0 + })) +}; diff --git a/gitlab-pages/docs/intro/what-and-why.md b/gitlab-pages/docs/intro/what-and-why.md index fdd1d2887..f9e627efd 100644 --- a/gitlab-pages/docs/intro/what-and-why.md +++ b/gitlab-pages/docs/intro/what-and-why.md @@ -1,14 +1,73 @@ --- id: what-and-why -title: What & Why +title: Michelson and LIGO --- -Before we get into what LIGO is and why LIGO needs to exist, let's take a look at what options the Tezos blockchain offers us out of the box. If you want to implement smart contracts natively on Tezos, you have to learn [Michelson](https://tezos.gitlab.io/whitedoc/michelson.html). +Before we get into what LIGO is and why LIGO needs to exist, let us +take a look at what options the Tezos blockchain offers us out of the +box. If you want to implement smart contracts natively on Tezos, you +have to learn +[Michelson](https://tezos.gitlab.io/whitedoc/michelson.html). -> 💡 The (Michelson) language is stack-based, with high level data types and primitives and strict static type checking. +**The rationale and design of Michelson** +The language native to the Tezos blockchain for writing smart +contracts is *Michelson*, a Domain-Specific Language (DSL) inspired by +Lisp and Forth. This unusual lineage aims at satisfying unusual +constraints, but entails some tensions in the design. -Here's an example of Michelson code: +First, to measure stepwise gas consumption, *Michelson is interpreted*. + +On the one hand, to assess gas usage per instruction, instructions +should be simple, which points to low-level features (a RISC-like +language). On the other hand, it was originally thought that users +will want to write in Michelson instead of lowering a language to +Michelson, because the gas cost would otherwise be harder to +predict. This means that *high-level features* were deemed necessary +(like a restricted variant of Lisp lambdas, a way to encode algebraic +data types, as well as built-in sets, maps and lists). + +To avoid ambiguous and otherwise misleading contracts, the layout of +Michelson contracts has been constrained (e.g., indentation, no +UTF-8), and a *canonical form* was designed and enforced when storing +contracts on the chain. + +To reduce the size of the code, Michelson was designed as *a +stack-based language*, whence the lineage from Forth and other +concatenative languages like PostScript, Joy, Cat, Factor etc. (Java +bytecode would count too.) + +Programs in those languages are *compact* because they assume an +implicit stack in which some input values are popped, and output +values are pushed, according to the current instruction being +executed. + +*Each Michelson instruction modifies a prefix of the stack*, that is, +a segment starting at the top. + +Whilst the types of Michelson instructions can be polymorphic, their +instantiations must be monomorphic, hence *Michelson instructions are +not first-class values* and cannot be partially interpreted. + +This enables a simple *static type checking*, as opposed to a complex +type inference. It can be performed efficiently: *contract type +checking consumes gas*. Basically, type checking aims at validating +the composition of instructions, therefore is key to safely composing +contracts (concatenation, activations). Once a contract passes type +checking, it cannot fail due to inconsistent assumptions on the +storage and other values (there are no null values, no casts), but it +can still fail for other reasons: division by zero, token exhaustion, +gas exhaustion, or an explicit `FAILWITH` instruction. This property +is called *type safety*. Also, such a contract cannot remain stuck: +this is the *progress property*. + +The existence of a formal type system for Michelson, of a formal +specification of its dynamic semantics (evaluation), of a Michelson +interpreter in Coq, of proofs in Coq of properties of some typical +contracts, all those achievements are instances of *formal methods in +Tezos*. + +Here is an example of a Michelson contract. **`counter.tz`** ```text @@ -21,118 +80,167 @@ Here's an example of Michelson code: NIL operation ; PAIR } } ``` -The contract above maintains an `int` in its storage. It has two entrypoints *(functions)* `add` and `sub` to modify it, and the default *entrypoint* of type unit will reset it to 0. +The contract above maintains an `int` as its storage. It has two +[entrypoints](https://tezos.gitlab.io/whitedoc/michelson.html#entrypoints), +`add` and `sub`, to modify it, and the `default` entrypoint of type +`unit` will reset it to `0`. -The contract itself contains three main parts: +The contract itself contains three sections: +- `parameter` - The argument provided by a transaction invoking the contract. +- `storage` - The type definition for the contract's data storage. +- `code` - Actual Michelson code that has the provided parameter and + the current storage value in its initial stack. It outputs in the + resulting stack a pair made of a list of operations and a new + storage value. -- `parameter` - Argument provided by a transaction invoking the contract -- `storage` - Type definition for the contract's data storage. -- `code` - Actual Michelson code that has the provided parameter & the current storage value in its initial stack. It outputs a pair of operations and a new storage value as its resulting stack. +Michelson code consists of *instructions* like `IF_LEFT`, `PUSH ...`, +`UNPAIR` etc. that are composed sequentially in what is called a +*sequence*. The implicit stack contains at all times the state of the +evaluation of the program, whilst the storage represents the +persistent state. If the contract execution is successful, the new +storage state will be committed to the chain and become visible to all +the nodes. Instructions are used to transform a prefix of the stack, +that is, the topmost part of it, for example, by duplicating its top +element, dropping it, subtracting the first two etc. -Michelson code consists of *instructions* like `IF_LEFT`, `PUSH ...`, `UNPAIR` that are bundled togeter in what is called a *sequence*. Stack represents an intermediate state of the program, while **storage represents a persistent state**. Instructions are used to modify the run-time stack in order to yield a desired stack value when the program terminates. +> 💡 A Michelson program running on the Tezos blockchain is meant to +> output a pair of values including a `list of operations` to include +> in a transaction, and a new `storage` value to persist on the chain. -> 💡 A Michelson program running on the Tezos blockchain is meant to output a pair of values including a `list of operations` to emit and a new `storage` value to persist +## Stack versus variables -## Differences between a stack and traditional variable management - -Stack management might be a little bit challanging, especially if you're coming from a *C-like language*. Let's implement a similar program in Javascript: +Perhaps the biggest challenge when programming in Michelson is the +lack of *variables* to denote the data: the stack layout has to be +kept in mind when retrieving and storing data. For example, let us +implement a program in Javascript that is similar to the Michelson +above: **`counter.js`** ```javascript var storage = 0; -function add(a) { - storage += a -} +function add (a) { storage += a; } +function sub (a) { storage -= a; } -function sub(a) { - storage -= a -} +// We are calling this function "reset" instead of "default" +// because `default` is a Javascript keyword -// We're calling this function reset instead of default -// because `default` is a javascript keyword -function reset() { - storage = 0; -} +function reset () { storage = 0; } ``` -In our javascript program the initial `storage` value is `0` and it can be modified by running the functions `add(a)`, `sub(a)` and `reset()`. +In our Javascript program the initial `storage` value is `0` and it +can be modified by calling `add (a)`, `sub (a)` and `reset ()`. -Unfortunately (???), we **can't run Javascript on the Tezos blockchain** at the moment. But we can choose LIGO, which will abstract the stack management and allow us to create readable, type-safe, and efficient smart contracts. +We cannot run Javascript on the Tezos blockchain, but we can choose +LIGO, which will abstract the stack management and allow us to create +readable, type-safe, and efficient smart contracts. -> 💡 You can try running the javascript program [here](https://codepen.io/maht0rz/pen/dyyvoPQ?editors=0012) +## LIGO for Programming Smart Contracts on Tezos -## C-like smart contracts instead of Michelson +Perhaps the most striking feature of LIGO is that it comes in +different concrete syntaxes, and even different programming +paradigms. In other words, LIGO is not defined by one syntax and one +paradigm, like imperative versus functional. -Let's take a look at a similar LIGO program. Don't worry if it's a little confusing at first; we'll explain all the syntax in the upcoming sections of the documentation. + - There is **PascaLIGO**, which is inspired by Pascal, hence is an + imperative language with lots of keywords, where values can be + locally mutated after they have been annotated with their types + (declaration). + + - There is **CameLIGO**, which is inspired by the pure subset of + [OCaml](https://ocaml.org/), hence is a functional language with + few keywords, where values cannot be mutated, but still require + type annotations (unlike OCaml, whose compiler performs almost + full type inference). + + - There is **ReasonLIGO**, which is inspired by the pure subset of + [ReasonML](https://reasonml.github.io/), which is based upon + OCaml. + +Let us decline the same LIGO contract in the three flavours above. Do +not worry if it is a little confusing at first; we will explain all +the syntax in the upcoming sections of the documentation. -```pascaligo -type action is -| Increment of int -| Decrement of int -| Reset of unit +```pascaligo group=a +type storage is int -function main (const p : action ; const s : int) : (list(operation) * int) is - block { skip } with ((nil : list(operation)), - case p of - | Increment(n) -> s + n - | Decrement(n) -> s - n - | Reset(n) -> 0 +type parameter is + Increment of int +| Decrement of int +| Reset + +type return is list (operation) * storage + +function main (const action : parameter; const store : storage) : return is + ((nil : list (operation)), + case action of + Increment (n) -> store + n + | Decrement (n) -> store - n + | Reset -> 0 end) ``` -```cameligo -type action = -| Increment of int -| Decrement of int -| Reset of unit +```cameligo group=a +type storage = int -let main (p, s: action * int) : operation list * int = - let result = - match p with - | Increment n -> s + n - | Decrement n -> s - n - | Reset n -> 0 - in - (([]: operation list), result) +type parameter = + Increment of int +| Decrement of int +| Reset + +type return = operation list * storage + +let main (action, store : parameter * storage) : return = + ([] : operation list), + (match action with + Increment n -> store + n + | Decrement n -> store - n + | Reset -> 0) ``` -```reasonligo -type action = -| Increment(int) -| Decrement(int) -| Reset(unit); +```reasonligo group=a +type storage = int; -let main = ((p,s): (action, int)) : (list(operation), int) => { - let result = - switch (p) { - | Increment(n) => s + n - | Decrement(n) => s - n - | Reset n => 0 - }; - (([]: list(operation)), result); +type parameter = + Increment (int) +| Decrement (int) +| Reset; + +type return = (list (operation), storage); + +let main = ((action, store): (parameter, storage)) : return => { + (([] : list (operation)), + (switch (action) { + | Increment (n) => store + n + | Decrement (n) => store - n + | Reset => 0})); }; ``` + + -> 💡 You can find the Michelson compilation output of the contract above in **`ligo-counter.tz`** +This LIGO contract behaves almost exactly* like the Michelson +contract we saw first, and it accepts the following LIGO expressions: +`Increment(n)`, `Decrement(n)` and `Reset`. Those serve as +`entrypoint` identification, same as `%add` `%sub` or `%default` in +the Michelson contract. -The LIGO contract behaves exactly* like the Michelson contract we've saw first, and it accepts the following LIGO expressions/values: `Increment(n)`, `Decrement(n)` and `Reset(n)`. Those serve as `entrypoint` identification, same as `%add` `%sub` or `%default` in the Michelson contract. - -**not exactly, the Michelson contract also checks if the `AMOUNT` sent is `0`* +**The Michelson contract also checks if the `AMOUNT` sent is `0`* --- ## Runnable code snippets & exercises Some of the sections in this documentation will include runnable code snippets and exercises. Sources for those are available at -the [LIGO Gitlab repository](https://gitlab.com/ligolang/ligo). +the [LIGO Gitlab repository](https://gitlab.com/ligolang/ligo). ### Snippets For example **code snippets** for the *Types* subsection of this doc, can be found here: diff --git a/gitlab-pages/docs/language-basics/boolean-if-else.md b/gitlab-pages/docs/language-basics/boolean-if-else.md index d938f5b7b..56d565cec 100644 --- a/gitlab-pages/docs/language-basics/boolean-if-else.md +++ b/gitlab-pages/docs/language-basics/boolean-if-else.md @@ -9,7 +9,7 @@ The type of a boolean value is `bool`. Here is how to define a boolean value: - + ```pascaligo group=a const a : bool = True // Notice the capital letter const b : bool = False // Same. @@ -19,7 +19,6 @@ const b : bool = False // Same. let a : bool = true let b : bool = false ``` - ```reasonligo group=a let a : bool = true; @@ -27,8 +26,7 @@ let b : bool = false; ``` - -## Comparing two Values +## Comparing Values In LIGO, only values of the same type can be compared. Moreover, not all values of the same type can be compared, only those with @@ -42,7 +40,7 @@ function. ### Comparing Strings - + ```pascaligo group=b const a : string = "Alice" const b : string = "Alice" @@ -62,11 +60,10 @@ let c : bool = (a == b); // true ``` - ### Comparing numbers - + ```pascaligo group=c const a : int = 5 const b : int = 4 @@ -102,14 +99,13 @@ let h : bool = (a != b); ``` - ### Comparing tez > 💡 Comparing `tez` values is especially useful when dealing with an > amount sent in a transaction. - + ```pascaligo group=d const a : tez = 5mutez const b : tez = 10mutez @@ -136,7 +132,7 @@ Conditional logic enables forking the control flow depending on the state. - + ```pascaligo group=e type magnitude is Small | Large // See variant types. @@ -183,5 +179,4 @@ ligo run-function gitlab-pages/docs/language-basics/boolean-if-else/cond.religo compare 21n' # Outputs: Large ``` - diff --git a/gitlab-pages/docs/language-basics/functions.md b/gitlab-pages/docs/language-basics/functions.md index e68c93ed8..9fe1ff4f2 100644 --- a/gitlab-pages/docs/language-basics/functions.md +++ b/gitlab-pages/docs/language-basics/functions.md @@ -3,47 +3,42 @@ id: functions title: Functions --- -Writing code is fun as long as it does not get out of hand. To make -sure our code does not turn into spaghetti, we can structure some -logic into functions. +LIGO features functions are the basic building block of contracts. For +example, entrypoints are functions. -## Blocks +## Declaring Functions + + + + +There are two ways in PascaLIGO to define functions: with or without a +*block*. + +### Blocks In PascaLIGO, *blocks* enable the sequential composition of instructions into an isolated scope. Each block needs to include at -least one instruction. If we need a placeholder, we use the -instruction `skip` which leaves the state unchanged. The rationale -for `skip` instead of a truly empty block is that it prevents you from -writing an empty block by mistake. - - - +least one instruction. ```pascaligo skip -// terse style block { a := a + 1 } -// verbose style -begin - a := a + 1 -end ``` -Blocks are more versatile than simply containing instructions: -they can also include *declarations* of values, like so: + +If we need a placeholder, we use the instruction `skip` which leaves +the state unchanged. The rationale for `skip` instead of a truly +empty block is that it prevents you from writing an empty block by +mistake. + ```pascaligo skip -// terse style -block { const a : int = 1 } -// verbose style -begin - const a : int = 1 -end +block { skip } ``` - +Blocks are more versatile than simply containing instructions: they +can also include *declarations* of values, like so: -## Defining a function - - - +```pascaligo skip +block { const a : int = 1 } +``` Functions in PascaLIGO are defined using the `function` keyword followed by their `name`, `parameters` and `return` type definitions. @@ -60,15 +55,23 @@ function add (const a : int; const b : int) : int is The function body consists of two parts: -- `block { }` - logic of the function -- `with ` - the value returned by the function +- `block { }` is the logic of the function; +- `with ` is the value returned by the function. -#### Blockless functions +### Blockless functions + +Functions that can contain all of their logic into a single +*expression* can be defined without the need of a block: + +```pascaligo +function identity (const n : int) : int is block { skip } with n // Bad! Empty block not needed! + +function identity (const n : int) : int is n // Blockless +``` + +The value of the expression is implicitly returned by the +function. Another example is as follows: -Functions that can contain all of their logic into a single expression -can be defined without a block. Instead of a block, you put an -expression, whose value is implicitly returned by the function, like -so: ```pascaligo group=b function add (const a: int; const b : int) : int is a + b ``` @@ -134,10 +137,10 @@ ligo run-function gitlab-pages/docs/language-basics/src/functions/curry.mligo in The function body is a single expression, whose value is returned. - -Functions in ReasonLIGO are defined using the `let` keyword, like -other values. The difference is that a succession of parameters is -provided after the value name, followed by the return type. + Functions in ReasonLIGO are defined using the `let` +keyword, like other values. The difference is that a tuple of +parameters is provided after the value name, with its type, then +followed by the return type. Here is how you define a basic function that sums two integers: ```reasonligo group=b @@ -163,7 +166,7 @@ a key in a record or a map. Here is how to define an anonymous function: - + ```pascaligo group=c function increment (const b : int) : int is (function (const a : int) : int is a + 1) (b) @@ -194,7 +197,7 @@ ligo evaluate-value gitlab-pages/docs/language-basics/src/functions/anon.mligo a ```reasonligo group=c let increment = (b : int) : int => ((a : int) : int => a + 1)(b); -let a : int = increment (1); // a = 2 +let a : int = increment (1); // a == 2 ``` You can check the value of `a` defined above using the LIGO compiler @@ -212,7 +215,7 @@ the use case of having a list of integers and mapping the increment function to all its elements. - + ```pascaligo group=c function incr_map (const l : list (int)) : list (int) is list_map (function (const i : int) : int is i + 1, l) @@ -226,7 +229,7 @@ gitlab-pages/docs/language-basics/src/functions/incr_map.ligo incr_map # Outputs: [ 2 ; 3 ; 4 ] ``` - + ```cameligo group=c let incr_map (l : int list) : int list = List.map (fun (i : int) -> i + 1) l @@ -240,7 +243,7 @@ gitlab-pages/docs/language-basics/src/functions/incr_map.mligo incr_map # Outputs: [ 2 ; 3 ; 4 ] ``` - + ```reasonligo group=c let incr_map = (l : list (int)) : list (int) => List.map ((i : int) => i + 1, l); diff --git a/gitlab-pages/docs/language-basics/loops.md b/gitlab-pages/docs/language-basics/loops.md index 6ae699cd6..ce656ec86 100644 --- a/gitlab-pages/docs/language-basics/loops.md +++ b/gitlab-pages/docs/language-basics/loops.md @@ -7,36 +7,37 @@ title: Loops - + -General iteration in PascaLIGO takes the shape of "while" loops, which -should be familiar to programmers of imperative languages. Those loops -are of the form `while `. Their associated block is -repeatedly evaluated until the condition becomes true, or never -evaluated if the condition is false at the start. The loop never -terminates if the condition never becomes true. Because we are writing -smart contracts on Tezos, when the condition of a "while" loops fails -to become true, the execution will run out of gas and stop with a -failure anyway. +General iteration in PascaLIGO takes the shape of general loops, which +should be familiar to programmers of imperative languages as "while +loops". Those loops are of the form `while `. Their +associated block is repeatedly evaluated until the condition becomes +true, or never evaluated if the condition is false at the start. The +loop never terminates if the condition never becomes true. Because we +are writing smart contracts on Tezos, when the condition of a "while" +loops fails to become true, the execution will run out of gas and stop +with a failure anyway. Here is how to compute the greatest common divisors of two natural number by means of Euclid's algorithm: ```pascaligo group=a -function gcd (var x : nat; var y : nat) : nat is block { - if x < y then - block { - const z : nat = x; - x := y; y := z +function gcd (var x : nat; var y : nat) : nat is + block { + if x < y then + block { + const z : nat = x; + x := y; y := z + } + else skip; + var r : nat := 0n; + while y =/= 0n block { + r := x mod y; + x := y; + y := r } - else skip; - var r : nat := 0n; - while y =/= 0n block { - r := x mod y; - x := y; - y := r - } -} with x + } with x ``` You can call the function `gcd` defined above using the LIGO compiler @@ -64,6 +65,9 @@ to have a special type: if the type of the accumulator is `t`, then it must have the type `bool * t` (not simply `t`). It is the boolean value that denotes whether the stopping condition has been reached. +Here is how to compute the greatest common divisors of two natural +number by means of Euclid's algorithm: + ```cameligo group=a let iter (x,y : nat * nat) : bool * (nat * nat) = if y = 0n then false, (x,y) else true, (y, x mod y) @@ -86,7 +90,6 @@ let gcd (x,y : nat * nat) : nat = let x,y = Loop.fold_while iter (x,y) in x ``` - You can call the function `gcd` defined above using the LIGO compiler like so: ```shell @@ -113,6 +116,9 @@ accumulator is `t`, then it must have the type `bool * t` (not simply `t`). It is the boolean value that denotes whether the stopping condition has been reached. +Here is how to compute the greatest common divisors of two natural +number by means of Euclid's algorithm: + ```reasonligo group=a let iter = ((x,y) : (nat, nat)) : (bool, (nat, nat)) => if (y == 0n) { (false, (x,y)); } else { (true, (y, x mod y)); }; @@ -139,15 +145,15 @@ let gcd = ((x,y) : (nat, nat)) : nat => { ``` -## For Loops +## Bounded Loops - - +In addition to general loops, PascaLIGO features a specialised kind of +*loop to iterate over bounded intervals*. These loops are familiarly +known as "for loops" and they have the form `for to + `, which is familiar for programmers of +imperative languages. -To iterate over a range of integers you use a loop of the form `for - to `, which is -familiar for programmers of imperative languages. Note that, for the -sake of generality, the bounds are of type `int`, not `nat`. +Consider how to sum integers from `0` to `n`: ```pascaligo group=c function sum (var n : nat) : int is block { @@ -158,6 +164,8 @@ function sum (var n : nat) : int is block { } with acc ``` +(Please do not use that function: there exists a closed form formula.) + You can call the function `sum` defined above using the LIGO compiler like so: ```shell @@ -165,11 +173,6 @@ ligo run-function gitlab-pages/docs/language-basics/src/loops/sum.ligo sum 7n # Outputs: 28 ``` - - - - - PascaLIGO "for" loops can also iterate through the contents of a collection, that is, a list, a set or a map. This is done with a loop @@ -230,4 +233,3 @@ gitlab-pages/docs/language-basics/src/loops/collection.ligo sum_map 'map ["1"->1; "2"->2; "3"->3]' # Outputs: ( "123", 6 ) ``` - diff --git a/gitlab-pages/docs/language-basics/maps-records.md b/gitlab-pages/docs/language-basics/maps-records.md index 50ec7e8b8..59226b4e3 100644 --- a/gitlab-pages/docs/language-basics/maps-records.md +++ b/gitlab-pages/docs/language-basics/maps-records.md @@ -17,7 +17,8 @@ special operator (`.`). Let us first consider and example of record type declaration. - + + ```pascaligo group=a type user is record [ @@ -27,7 +28,7 @@ type user is ] ``` - + ```cameligo group=a type user = { id : nat; @@ -36,7 +37,7 @@ type user = { } ``` - + ```reasonligo group=a type user = { id : nat, @@ -49,7 +50,7 @@ type user = { And here is how a record value is defined: - + ```pascaligo group=a const alice : user = record [ @@ -59,7 +60,7 @@ const alice : user = ] ``` - + ```cameligo group=a let alice : user = { id = 1n; @@ -68,7 +69,7 @@ let alice : user = { } ``` - + ```reasonligo group=a let alice : user = { id : 1n, @@ -80,21 +81,21 @@ let alice : user = { ### Accessing Record Fields -If we want the contents of a given field, we use the `.` infix +If we want the contents of a given field, we use the (`.`) infix operator, like so: - + ```pascaligo group=a const alice_admin : bool = alice.is_admin ``` - + ```cameligo group=a let alice_admin : bool = alice.is_admin ``` - + ```reasonligo group=a let alice_admin: bool = alice.is_admin; ``` @@ -118,7 +119,7 @@ points on a plane. - + ```pascaligo group=b type point is record [x : int; y : int; z : int] type vector is record [dx : int; dy : int] @@ -142,7 +143,7 @@ You have to understand that `p` has not been changed by the functional update: a namless new version of it has been created and returned by the blockless function. - + The syntax for the functional updates of record in CameLIGO follows that of OCaml: @@ -156,7 +157,6 @@ let origin : point = {x = 0; y = 0; z = 0} let xy_translate (p, vec : point * vector) : point = {p with x = p.x + vec.dx; y = p.y + vec.dy} ``` - You can call the function `xy_translate` defined above by running the following command of the shell: @@ -171,7 +171,7 @@ xy_translate "({x=2;y=3;z=1}, {dx=3;dy=4})" > functional update: a nameless new version of it has been created and > returned. - + The syntax for the functional updates of record in ReasonLIGO follows that of OCaml: @@ -187,7 +187,7 @@ let xy_translate = ((p, vec) : (point, vector)) : point => ``` -You can call the function `x_translation` defined above by running the +You can call the function `xy_translate` defined above by running the following command of the shell: ```shell ligo run-function @@ -213,9 +213,6 @@ name "patch"). Let us consider defining a function that translates three-dimensional points on a plane. - - - ```pascaligo group=c type point is record [x : int; y : int; z : int] type vector is record [dx : int; dy : int] @@ -273,9 +270,10 @@ type vector is record [dx : int; dy : int] const origin : point = record [x = 0; y = 0; z = 0] -function xy_translate (var p : point; const vec : vector) : point is block { - const p : point = p with record [x = p.x + vec.dx; y = p.y + vec.dy] -} with p +function xy_translate (var p : point; const vec : vector) : point is + block { + const p : point = p with record [x = p.x + vec.dx; y = p.y + vec.dy] + } with p ``` You can call the new function `xy_translate` defined above by running the @@ -289,9 +287,6 @@ xy_translate "(record [x=2;y=3;z=1], record [dx=3;dy=4])" The hiding of a variable by another (here `p`) is called `shadowing`. - - - ## Maps *Maps* are a data structure which associate values of the same type to @@ -304,19 +299,19 @@ Here is how a custom map from addresses to a pair of integers is defined. - + ```pascaligo group=f type move is int * int type register is map (address, move) ``` - + ```cameligo group=f type move = int * int type register = (address, move) map ``` - + ```reasonligo group=f type move = (int, int); type register = map (address, move); @@ -326,7 +321,7 @@ type register = map (address, move); And here is how a map value is defined: - + ```pascaligo group=f const moves : register = @@ -340,7 +335,7 @@ const moves : register = > address)` means that we cast a string into an address. Also, `map` > is a keyword. - + ```cameligo group=f let moves : register = Map.literal [ @@ -353,7 +348,7 @@ let moves : register = > separate individual map entries. `("": address)` > means that we type-cast a string into an address. - + ```reasonligo group=f let moves : register = Map.literal ([ @@ -375,19 +370,19 @@ associated to a given key (`address` here) in the register. Here is an example: - + ```pascaligo group=f const my_balance : option (move) = moves [("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address)] ``` - + ```cameligo group=f let my_balance : move option = Map.find_opt ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address) moves ``` - + ```reasonligo group=f let my_balance : option (move) = Map.find_opt (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address), moves); @@ -400,7 +395,7 @@ the reader to account for a missing key in the map. This requires - + ```pascaligo group=f function force_access (const key : address; const moves : register) : move is case moves[key] of @@ -409,7 +404,7 @@ function force_access (const key : address; const moves : register) : move is end ``` - + ```cameligo group=f let force_access (key, moves : address * register) : move = match Map.find_opt key moves with @@ -417,7 +412,7 @@ let force_access (key, moves : address * register) : move = | None -> (failwith "No move." : move) ``` - + ```reasonligo group=f let force_access = ((key, moves) : (address, register)) : move => { switch (Map.find_opt (key, moves)) { @@ -438,7 +433,7 @@ those operations are called *updates*. - + The values of a PascaLIGO map can be updated using the usual assignment syntax `[] := `. Let us @@ -464,7 +459,7 @@ function assignments (var m : register) : register is } with m ``` - + We can update a binding in a map in CameLIGO by means of the `Map.update` built-in function: @@ -479,7 +474,7 @@ let assign (m : register) : register = > use `None` instead, that would have meant that the binding is > removed. - + We can update a binding in a map in ReasonLIGO by means of the `Map.update` built-in function: @@ -501,7 +496,7 @@ To remove a binding from a map, we need its key. - + In PascaLIGO, there is a special instruction to remove a binding from a map. @@ -512,13 +507,19 @@ function delete (const key : address; var moves : register) : register is } with moves ``` - + + +In CameLIGO, we use the predefined function `Map.remove` as follows: + ```cameligo group=f let delete (key, moves : address * register) : register = Map.remove key moves ``` - + + +In ReasonLIGO, we use the predefined function `Map.remove` as follows: + ```reasonligo group=f let delete = ((key, moves) : (address, register)) : register => { Map.remove (key, moves); @@ -528,51 +529,85 @@ let delete = ((key, moves) : (address, register)) : register => { -### Iterating Functionally over a Map +### Functional Iteration over Maps A *functional iterator* is a function that traverses a data structure and calls in turn a given function over the elements of that structure to compute some value. Another approach is possible in PascaLIGO: *loops* (see the relevant section). -There are three kinds of functional iteration over LIGO maps: `iter`, -`map` and `fold`. The first, `iter`, is an iteration over the map with +There are three kinds of functional iterations over LIGO maps: the +*iterated operation*, the *map operation* (not to be confused with the +*map data structure*) and the *fold operation*. + +#### Iterated Operation + +The first, the *iterated operation*, is an iteration over the map with no return value: its only use is to produce side-effects. This can be useful if for example you would like to check that each value inside of a map is within a certain range, and fail with an error otherwise. - + + + +In PascaLIGO, the predefined functional iterator implementing the +iterated operation over maps is called `map_iter`. In the following +example, the register of moves is iterated to check that the start of +each move is above `3`. + ```pascaligo group=f function iter_op (const m : register) : unit is block { - function aggregate (const i : address; const j : move) : unit is block - { if j.1 > 1 then skip else failwith ("Below range.") } with unit - } with map_iter (aggregate, m) + function iterated (const i : address; const j : move) : unit is + if j.1 > 3 then Unit else (failwith ("Below range.") : unit) + } with map_iter (iterated, m) ``` - +> The iterated function must be pure, that is, it cannot mutate +> variables. + + + +In CameLIGO, the predefinded functional iterator implementing the +iterated operation over maps is called `Map.iter`. In the following +example, the register of moves is iterated to check that the start of +each move is above `3`. + ```cameligo group=f let iter_op (m : register) : unit = - let assert_eq = fun (i,j : address * move) -> assert (j.0 > 1) - in Map.iter assert_eq m + let predicate = fun (i,j : address * move) -> assert (j.0 > 3) + in Map.iter predicate m ``` - + + +In ReasonLIGO, the predefined functional iterator implementing the +iterated operation over maps is called `Map.iter`. In the following +example, the register of moves is iterated to check that the start of +each move is above `3`. + ```reasonligo group=f let iter_op = (m : register) : unit => { - let assert_eq = ((i,j) : (address, move)) => assert (j[0] > 1); - Map.iter (assert_eq, m); + let predicate = ((i,j) : (address, move)) => assert (j[0] > 3); + Map.iter (predicate, m); }; ``` +#### Map Operation + We may want to change all the bindings of a map by applying to them a -function. This is also called a *map operation*, as opposed to the -*map data structure* we have been presenting. +function. This is called a *map operation*, not to be confused with +the map data structure. - + + + +In PascaLIGO, the predefined functional iterator implementing the map +operation over maps is called `map_map`and is used as follows: + ```pascaligo group=f function map_op (const m : register) : register is block { @@ -581,49 +616,78 @@ function map_op (const m : register) : register is } with map_map (increment, m) ``` - +> The mapped function must be pure, that is, it cannot mutate +> variables. + + + +In CameLIGO, the predefined functional iterator implementing the map +operation over maps is called `Map.map` and is used as follows: + ```cameligo group=f let map_op (m : register) : register = let increment = fun (i,j : address * move) -> j.0, j.1 + 1 in Map.map increment m ``` - + + +In ReasonLIGO, the predefined functional iteratir implementing the map +operation over maps is called `Map.map` and is used as follows: + ```reasonligo group=f let map_op = (m : register) : register => { let increment = ((i,j): (address, move)) => (j[0], j[1] + 1); - Map.map(increment, m); + Map.map (increment, m); }; ``` -A *fold operation* is the most general of iterations. The iterated +#### Fold Operation + +A *fold operation* is the most general of iterations. The folded function takes two arguments: an *accumulator* and the structure *element* at hand, with which it then produces a new accumulator. This enables having a partial result that becomes complete when the traversal of the data structure is over. - + + + +In PascaLIGO, the predefined functional iterator implementing the fold +operation over maps is called `map_fold` and is used as follows: + ```pascaligo group=f function fold_op (const m : register) : int is block { - function aggregate (const j : int; const cur : address * move) : int is + function iterated (const j : int; const cur : address * move) : int is j + cur.1.1 - } with map_fold (aggregate, m, 5) + } with map_fold (iterated, m, 5) ``` - +> The folded function must be pure, that is, it cannot mutate +> variables. + + + +In CameLIGO, the predefined functional iterator implementing the fold +operation over maps is called `Map.fold` and is used as follows: + ```cameligo group=f let fold_op (m : register) : register = - let aggregate = fun (i,j : int * (address * move)) -> i + j.1.1 - in Map.fold aggregate m 5 + let iterated = fun (i,j : int * (address * move)) -> i + j.1.1 + in Map.fold iterated m 5 ``` - + + +In ReasonLIGO, the predefined functional iterator implementing the +fold operation over maps is called `Map.fold` and is used as follows: + ```reasonligo group=f let fold_op = (m : register) : register => { - let aggregate = ((i,j): (int, (address, move))) => i + j[1][1]; - Map.fold (aggregate, m, 5); + let iterated = ((i,j): (int, (address, move))) => i + j[1][1]; + Map.fold (iterated, m, 5); }; ``` @@ -643,32 +707,32 @@ interface for big maps is analogous to the one used for ordinary maps. Here is how we define a big map: - + ```pascaligo group=g type move is int * int type register is big_map (address, move) ``` - + ```cameligo group=g type move = int * int type register = (address, move) big_map ``` - + ```reasonligo group=g type move = (int, int); -type register = big_map(address, move); +type register = big_map (address, move); ``` And here is how a map value is created: - + ```pascaligo group=g const moves : register = @@ -682,7 +746,7 @@ const moves : register = > `("" : address)` means that we cast a string into an > address. - + ```cameligo group=g let moves : register = @@ -696,7 +760,7 @@ let moves : register = > separating individual map entries. The annotated value `(" value>" : address)` means that we cast a string into an address. - + ```reasonligo group=g let moves : register = @@ -713,28 +777,30 @@ let moves : register = -### Accessing Values by Key +### Accessing Values If we want to access a move from our `register` above, we can use the postfix `[]` operator to read the associated `move` value. However, -the value we read is an optional value: in our case, of type `option -(move)`. Here is an example: +the value we read is an optional value (in our case, of type `option +(move)`), to account for a missing key. Here is an example: - + + + ```pascaligo group=g const my_balance : option (move) = moves [("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address)] ``` - + ```cameligo group=g let my_balance : move option = Big_map.find_opt ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address) moves ``` - + ```reasonligo group=g let my_balance : option (move) = @@ -742,23 +808,25 @@ let my_balance : option (move) = ``` -### Updating a Big Map +### Updating Big Maps - + The values of a PascaLIGO big map can be updated using the assignment syntax for ordinary maps ```pascaligo group=g -function assign (var m : register) : register is +function add (var m : register) : register is block { m [("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address)] := (4,9) } with m + +const updated_map : register = add (moves) ``` - + We can update a big map in CameLIGO using the `Big_map.update` built-in: @@ -769,7 +837,7 @@ let updated_map : register = ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address) (Some (4,9)) moves ``` - + We can update a big map in ReasonLIGO using the `Big_map.update` built-in: @@ -780,6 +848,47 @@ let updated_map : register = (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address), Some((4,9)), moves); ``` -### Removing Bindings from a Map + + +### Removing Bindings + +Removing a binding in a map is done differently according to the LIGO +syntax. + + + + + +PascaLIGO features a special syntactic construct to remove bindings +from maps, of the form `remove from map `. For example, + +```pascaligo group=g +function rem (var m : register) : register is + block { + remove ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address) from map moves + } with m + +const updated_map : register = rem (moves) +``` + + + +In CameLIGO, the predefined function which removes a binding in a map +is called `Map.remove` and is used as follows: + +```cameligo group=g +let updated_map : register = + Map.remove ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address) moves +``` + + + +In ReasonLIGO, the predefined function which removes a binding in a map +is called `Map.remove` and is used as follows: + +```reasonligo group=g +let updated_map : register = + Map.remove (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address), moves) +``` diff --git a/gitlab-pages/docs/language-basics/math-numbers-tez.md b/gitlab-pages/docs/language-basics/math-numbers-tez.md index bb274cd7c..11a589c12 100644 --- a/gitlab-pages/docs/language-basics/math-numbers-tez.md +++ b/gitlab-pages/docs/language-basics/math-numbers-tez.md @@ -18,8 +18,7 @@ adding a value of type `int` to a value of type `tez` is invalid. Note that adding an integer to a natural number produces an integer. - - + ```pascaligo group=a // int + int yields int const a : int = 5 + 10 @@ -50,7 +49,6 @@ const g : int = 1_000_000 >``` - ```cameligo group=a // int + int yields int let a : int = 5 + 10 @@ -81,7 +79,6 @@ let g : int = 1_000_000 >``` - ```reasonligo group=a // int + int yields int let a : int = 5 + 10; @@ -99,7 +96,7 @@ let c : tez = 5mutez + 10mutez; let e : nat = 5n + 10n; // nat + int yields an int: invalid -//let f : nat = 5n + 10; +// let f : nat = 5n + 10; let g : int = 1_000_000; ``` @@ -109,7 +106,6 @@ let g : int = 1_000_000; >```reasonligo >let sum : tex = 100_000mutez; >``` - ## Subtraction @@ -119,7 +115,7 @@ Subtraction looks as follows. > ⚠️ Even when subtracting two `nats`, the result is an `int` - + ```pascaligo group=b const a : int = 5 - 10 @@ -166,7 +162,7 @@ let d : tez = 5mutez - 1mutez; You can multiply values of the same type, such as: - + ```pascaligo group=c const a : int = 5 * 5 @@ -200,7 +196,7 @@ In LIGO you can divide `int`, `nat`, and `tez`. Here is how: > ⚠️ Division of two `tez` values results into a `nat` - + ```pascaligo group=d const a : int = 10 / 3 const b : nat = 10n / 3n @@ -248,11 +244,11 @@ let b : nat = abs (1); -## Check if a value is a `nat` +## Checking a `nat` -You can check if a value is a `nat` by using a syntax specific -built-in function, which accepts an `int` and returns an optional -`nat`: if `Some(nat)` then the provided integer was indeed a natural +You can check if a value is a `nat` by using a predefined cast +function which accepts an `int` and returns an optional `nat`: if the +result is not `None`, then the provided integer was indeed a natural number, and not otherwise. diff --git a/gitlab-pages/docs/language-basics/sets-lists-tuples.md b/gitlab-pages/docs/language-basics/sets-lists-tuples.md index e43de8200..8da5b6300 100644 --- a/gitlab-pages/docs/language-basics/sets-lists-tuples.md +++ b/gitlab-pages/docs/language-basics/sets-lists-tuples.md @@ -3,11 +3,8 @@ id: sets-lists-tuples title: Tuples, Lists, Sets --- -Apart from complex data types such as `maps` and `records`, ligo also -exposes `tuples`, `lists` and `sets`. - -> ⚠️ Make sure to pick the appropriate data type for your use case, and -> bear in mind the related gas costs. +Apart from complex data types such as `maps` and `records`, LIGO also +features `tuples`, `lists` and `sets`. ## Tuples @@ -15,16 +12,16 @@ Tuples gather a given number of values in a specific order and those values, called *components*, can be retrieved by their index (position). Probably the most common tuple is the *pair*. For example, if we were storing coordinates on a two dimensional grid we -might use a pair of type `int * int` to store the coordinates `x` and -`y` as the pair value `(x,y)`. There is a *specific order*, so `(y,x)` -is not equal to `(x,y)`. The number of components is part of the type -of a tuple, so, for example, we cannot add an extra component to a -pair and obtain a triple of the same type: `(x,y)` has always a -different type from `(x,y,z)`, whereas `(y,x)` may have the same type. +might use a pair `(x,y)` to store the coordinates `x` and `y`. There +is a *specific order*, so `(y,x)` is not equal to `(x,y)`. The number +of components is part of the type of a tuple, so, for example, we +cannot add an extra component to a pair and obtain a triple of the +same type, so, for instance, `(x,y)` has always a different type from +`(x,y,z)`, whereas `(y,x)` might have the same type as `(x,y)`. Like records, tuple components can be of arbitrary types. -### Defining a tuple +### Defining Tuples Unlike [a record](language-basics/maps-records.md), tuple types do not have to be defined before they can be used. However below we will give @@ -33,54 +30,55 @@ them names by *type aliasing*. -```pascaligo group=c + +```pascaligo group=tuple type full_name is string * string // Alias const full_name : full_name = ("Alice", "Johnson") ``` -```cameligo group=c + +```cameligo group=tuple type full_name = string * string // Alias -(* The parenthesis here are optional *) -let full_name : full_name = ("Alice", "Johnson") +let full_name : full_name = ("Alice", "Johnson") // Optional parentheses ``` -```reasonligo group=c + +```reasonligo group=tuple type full_name = (string, string); // Alias -(* The parenthesis here are optional *) let full_name : full_name = ("Alice", "Johnson"); ``` -### Accessing an Element in a Tuple +### Accessing Components Accessing the components of a tuple in OCaml is achieved by [pattern matching](language-basics/unit-option-pattern-matching.md). LIGO currently supports tuple patterns only in the parameters of functions, -not in pattern matching. In LIGO, however, we can access components by -their position in their tuple, which cannot be done in OCaml. +not in pattern matching. However, we can access components by their +position in their tuple, which cannot be done in OCaml. - + Tuple components are one-indexed like so: -```pascaligo group=c +```pascaligo group=tuple const first_name : string = full_name.1; ``` - + Tuple elements are zero-indexed and accessed like so: -```cameligo group=c +```cameligo group=tuple let first_name : string = full_name.0 ``` @@ -88,10 +86,12 @@ let first_name : string = full_name.0 Tuple components are one-indexed like so: -```reasonligo group=c +```reasonligo group=tuple let first_name : string = full_name[1]; ``` + + ## Lists Lists are linear collections of elements of the same type. Linear @@ -105,105 +105,183 @@ think of a list a *stack*, where the top is written on the left. > 💡 Lists are useful when returning operations from a smart > contract's entrypoint. -### Defining a List +### Defining Lists - -```pascaligo group=b + +```pascaligo group=lists const my_list : list (int) = list [1; 2; 2] // The head is 1 ``` -```cameligo group=b +```cameligo group=lists let my_list : int list = [1; 2; 2] // The head is 1 ``` -```reasonligo group=b +```reasonligo group=lists let my_list : list (int) = [1, 2, 2]; // The head is 1 ``` -### Adding to a List +### Adding to Lists Lists can be augmented by adding an element before the head (or, in terms of stack, by *pushing an element on top*). This operation is usually called *consing* in functional languages. + + + + In PascaLIGO, the *cons operator* is infix and noted `#`. It is not symmetric: on the left lies the element to cons, and, on the right, a list on which to cons. (The symbol is helpfully asymmetric to remind you of that.) +```pascaligo group=lists +const larger_list : list (int) = 5 # my_list // [5;1;2;2] +``` + + + In CameLIGO, the *cons operator* is infix and noted `::`. It is not symmetric: on the left lies the element to cons, and, on the right, a list on which to cons. +```cameligo group=lists +let larger_list : int list = 5 :: my_list // [5;1;2;2] +``` + + + In ReasonLIGO, the *cons operator* is infix and noted `, ...`. It is not symmetric: on the left lies the element to cons, and, on the right, a list on which to cons. - - -```pascaligo group=b -const larger_list : list (int) = 5 # my_list -``` - - -```cameligo group=b -let larger_list : int list = 5 :: my_list -``` - - -```reasonligo group=b -let larger_list : list (int) = [5, ...my_list]; +```reasonligo group=lists +let larger_list : list (int) = [5, ...my_list]; // [5,1,2,2] ``` -
- > 💡 Lists can be iterated, folded or mapped to different values. You > can find additional examples > [here](https://gitlab.com/ligolang/ligo/tree/dev/src/test/contracts) > and other built-in operators > [here](https://gitlab.com/ligolang/ligo/blob/dev/src/passes/operators/operators.ml#L59) -### Mapping of a List +### Functional Iteration over Lists -We may want to apply a function to all the elements of a list and -obtain the resulting list, in the same order. For example, we may want -to create a list that contains all the elements of another list -incremented by one. This is a special case of *fold operation* called -a *map operation*. Map operations (not to be confused by the -[map data structure](language-basics/maps-records.md)), are predefined -functions in LIGO. They take as a parameter the function to apply to -all the elements. Of course, that function must return a value of the -same type as the element. +A *functional iterator* is a function that traverses a data structure +and calls in turn a given function over the elements of that structure +to compute some value. Another approach is possible in PascaLIGO: +*loops* (see the relevant section). -In PascaLIGO, the map function is called `list_map`. +There are three kinds of functional iterations over LIGO maps: the +*iterated operation*, the *map operation* (not to be confused with the +*map data structure*) and the *fold operation*. -In CameLIGO and ReasonLIGO, the map function is called `List.map`. +#### Iterated Operation + +The first, the *iterated operation*, is an iteration over the map with +no return value: its only use is to produce side-effects. This can be +useful if for example you would like to check that each value inside +of a map is within a certain range, and fail with an error otherwise. - -```pascaligo group=b + + + +In PascaLIGO, the predefined functional iterator implementing the +iterated operation over lists is called `list_iter`. + +In the following example, a list is iterated to check that all its +elements (integers) are greater than `3`: + +```pascaligo group=lists +function iter_op (const l : list (int)) : unit is + block { + function iterated (const i : int) : unit is + if i > 2 then Unit else (failwith ("Below range.") : unit) + } with list_iter (iterated, l) +``` + +> The iterated function must be pure, that is, it cannot mutate +> variables. + + + +In CameLIGO, the predefined functional iterator implementing the +iterated operation over lists is called `List.iter`. + +In the following example, a list is iterated to check that all its +elements (integers) are greater than `3`: + +```cameligo group=lists +let iter_op (l : int list) : unit = + let predicate = fun (i : int) -> assert (i > 3) + in List.iter predicate l +``` + + + +In ReasonLIGO, the predefined functional iterator implementing the +iterated operation over lists is called `List.iter`. + +In the following example, a list is iterated to check that all its +elements (integers) are greater than `3`: + +```reasonligo group=lists +let iter_op = (l : list (int)) : unit => { + let predicate = (i : int) => assert (i > 3); + List.iter (predicate, l); +}; +``` + + + + +#### Map Operation + +We may want to change all the elements of a given list by applying to +them a function. This is called a *map operation*, not to be confused +with the map data structure. + + + + + +In PascaLIGO, the predefined functional iterator implementing the map +operation over lists is called `list_map` and is used as follows: + +```pascaligo group=lists function increment (const i : int): int is i + 1 // Creates a new list with all elements incremented by 1 const plus_one : list (int) = list_map (increment, larger_list) ``` + -```cameligo group=b + +In CameLIGO, the predefined functional iterator implementing the map +operation over lists is called `List.map` and is used as follows: + +```cameligo group=lists let increment (i : int) : int = i + 1 // Creates a new list with all elements incremented by 1 let plus_one : int list = List.map increment larger_list ``` + -```reasonligo group=b + +In ReasonLIGO, the predefined functional iterator implementing the map +operation over lists is called `List.map` and is used as follows: + +```reasonligo group=lists let increment = (i : int) : int => i + 1; // Creates a new list with all elements incremented by 1 @@ -212,33 +290,51 @@ let plus_one : list (int) = List.map (increment, larger_list); -### Folding of over a List +#### Fold Operation + +A *fold operation* is the most general of iterations. The folded +function takes two arguments: an *accumulator* and the structure +*element* at hand, with which it then produces a new accumulator. This +enables having a partial result that becomes complete when the +traversal of the data structure is over. - -```pascaligo group=b + + + +In PascaLIGO, the predefined functional iterator implementing the fold +operation over lists is called `list_fold` and is used as follows: + +```pascaligo group=lists function sum (const acc : int; const i : int): int is acc + i const sum_of_elements : int = list_fold (sum, my_list, 0) ``` +> The folded function must be pure, that is, it cannot mutate +> variables. + -```cameligo group=b +In CameLIGO, the predefined functional iterator implementing the fold +operation over lists is called `List.fold` and is used as follows: + +```cameligo group=lists let sum (acc, i: int * int) : int = acc + i let sum_of_elements : int = List.fold sum my_list 0 ``` -```reasonligo group=b +In ReasonLIGO, the predefined functional iterator implementing the +fold operation over lists is called `List.fold` and is used as follows: + +```reasonligo group=lists let sum = ((result, i): (int, int)): int => result + i; let sum_of_elements : int = List.fold (sum, my_list, 0); ``` - - ## Sets Sets are unordered collections of values of the same type, like lists @@ -249,56 +345,65 @@ whereas they can be repeated in a list. ### Empty Sets - -```pascaligo group=a + + + +In PascaLIGO, the notation for sets is similar to that for lists, +except the keyword `set` is used before: + +```pascaligo group=sets const my_set : set (int) = set [] ``` -```cameligo group=a -let my_set : int set = (Set.empty : int set) + +In CameLIGO, the empty set is denoted by the predefined value +`Set.empty`. + +```cameligo group=sets +let my_set : int set = Set.empty ``` + -```reasonligo group=a -let my_set : set (int) = (Set.empty : set (int)); + +In CameLIGO, the empty set is denoted by the predefined value +`Set.empty`. + +```reasonligo group=sets +let my_set : set (int) = Set.empty; ``` ### Non-empty Sets + + In PascaLIGO, the notation for sets is similar to that for lists, except the keyword `set` is used before: - - -```pascaligo group=a +```pascaligo group=sets const my_set : set (int) = set [3; 2; 2; 1] ``` - - You can check that `2` is not repeated in `my_set` by using the LIGO compiler like this (the output will sort the elements of the set, but that order is not significant for the compiler): - ```shell ligo evaluate-value gitlab-pages/docs/language-basics/src/sets-lists-tuples/sets.ligo my_set # Outputs: { 3 ; 2 ; 1 } ``` + + In CameLIGO, there is no predefined syntactic construct for sets: you must build your set by adding to the empty set. (This is the way in OCaml.) - - -```cameligo group=a +```cameligo group=sets let my_set : int set = Set.add 3 (Set.add 2 (Set.add 2 (Set.add 1 (Set.empty : int set)))) ``` - - You can check that `2` is not repeated in `my_set` by using the LIGO compiler like this (the output will sort the elements of the set, but that order is not significant for the compiler): @@ -309,17 +414,16 @@ gitlab-pages/docs/language-basics/src/sets-lists-tuples/sets.mligo my_set # Outputs: { 3 ; 2 ; 1 } ``` + + In ReasonLIGO, there is no predefined syntactic construct for sets: you must build your set by adding to the empty set. (This is the way in OCaml.) - - -```reasonligo group=a +```reasonligo group=sets let my_set : set (int) = Set.add (3, Set.add (2, Set.add (2, Set.add (1, Set.empty : set (int))))); ``` - You can check that `2` is not repeated in `my_set` by using the LIGO compiler like this (the output will sort the elements of the set, but @@ -330,25 +434,36 @@ ligo evaluate-value gitlab-pages/docs/language-basics/src/sets-lists-tuples/sets.religo my_set # Outputs: { 3 ; 2 ; 1 } ``` + ### Set Membership + + -PascaLIGO features a special keyword `constains` that operates like an +PascaLIGO features a special keyword `contains` that operates like an infix operator checking membership in a set. - - -```pascaligo group=a +```pascaligo group=sets const contains_3 : bool = my_set contains 3 ``` + -```cameligo group=a + +In CameLIGO, the predefined predicate `Set.mem` tests for membership +in a set as follows: + +```cameligo group=sets let contains_3 : bool = Set.mem 3 my_set ``` + -```reasonligo group=a + +In ReasonLIGO, the predefined predicate `Set.mem` tests for membership +in a set as follows: + +```reasonligo group=sets let contains_3 : bool = Set.mem (3, my_set); ``` @@ -357,37 +472,50 @@ let contains_3 : bool = Set.mem (3, my_set); ### Cardinal - -```pascaligo group=a + + + +In PascaLIGO, the predefined function `size` returns the number of +elements in a given set as follows: + +```pascaligo group=sets const set_size : nat = size (my_set) ``` -```cameligo group=a + +In CameLIGO, the predefined function `Set.size` returns the number of +elements in a given set as follows: + +```cameligo group=sets let set_size : nat = Set.size my_set ``` -```reasonligo group=a + +In ReasonLIGO, the predefined function `Set.size` returns the number +of elements in a given set as follows: + +```reasonligo group=sets let set_size : nat = Set.size (my_set); ``` + -### Adding or Removing from a Set - - - -In PascaLIGO, there are two ways to update a set. Either we create a -new set from the given one, or we modify it in-place. First, let us -consider the former: +### Updating Sets - -```pascaligo group=a + + + +In PascaLIGO, there are two ways to update a set, that is to add or +remove from it. Either we create a new set from the given one, or we +modify it in-place. First, let us consider the former way + +```pascaligo group=sets const larger_set : set (int) = set_add (4, my_set) const smaller_set : set (int) = set_remove (3, my_set) ``` - If we are in a block, we can use an instruction to modify the set bound to a given variable. This is called a *patch*. It is only @@ -400,37 +528,31 @@ this instruction is equivalent to perform the union of two sets, one that is modified in-place, and the other given as a literal (extensional definition). - - -```pascaligo group=a +```pascaligo group=sets function update (var s : set (int)) : set (int) is block { patch s with set [4; 7] } with s const new_set : set (int) = update (my_set) ``` - + In CameLIGO, we update a given set by creating another one, with or without some elements. - - -```cameligo group=a +```cameligo group=sets let larger_set : int set = Set.add 4 my_set let smaller_set : int set = Set.remove 3 my_set ``` - + In ReasonLIGO, we update a given set by creating another one, with or without some elements. - - -```reasonligo group=a +```reasonligo group=sets let larger_set : set (int) = Set.add (4, my_set); let smaller_set : set (int) = Set.remove (3, my_set); @@ -438,32 +560,149 @@ let smaller_set : set (int) = Set.remove (3, my_set); -### Folding over a Set +### Functional Iteration over Sets +A *functional iterator* is a function that traverses a data structure +and calls in turn a given function over the elements of that structure +to compute some value. Another approach is possible in PascaLIGO: +*loops* (see the relevant section). -Given a set, we may want to apply a function in turn to all the -elements it contains, while accumulating some value which is returned -at the end. This is a *fold operation*. In the following example, we -sum up all the elements of the set `my_set` defined above. +There are three kinds of functional iterations over LIGO maps: the +*iterated operation*, the *map operation* (not to be confused with the +*map data structure*) and the *fold operation*. +#### Iterated Operation -In PascaLIGO, the folded function takes the accumulator first and the -(current) set element second. The predefined fold is called `set_fold`. +The first, the *iterated operation*, is an iteration over the map with +no return value: its only use is to produce side-effects. This can be +useful if for example you would like to check that each value inside +of a map is within a certain range, and fail with an error otherwise. - -```pascaligo group=a + + + +In PascaLIGO, the predefined functional iterator implementing the +iterated operation over sets is called `set_iter`. + +In the following example, a set is iterated to check that all its +elements (integers) are greater than `3`: + +```pascaligo group=sets +function iter_op (const s : set (int)) : unit is + block { + function iterated (const i : int) : unit is + if i > 2 then Unit else (failwith ("Below range.") : unit) + } with set_iter (iterated, s) +``` + +> The iterated function must be pure, that is, it cannot mutate +> variables. + + + +In CameLIGO, the predefined functional iterator implementing the +iterated operation over sets is called `Set.iter`. + +In the following example, a set is iterated to check that all its +elements (integers) are greater than `3`: + +```cameligo group=sets +let iter_op (s : int set) : unit = + let predicate = fun (i : int) -> assert (i > 3) + in Set.iter predicate s +``` + + + +In ReasonLIGO, the predefined functional iterator implementing the +iterated operation over sets is called `Set.iter`. + +In the following example, a set is iterated to check that all its +elements (integers) are greater than `3`: + +```reasonligo group=sets +let iter_op = (s : set (int)) : unit => { + let predicate = (i : int) => assert (i > 3); + Set.iter (predicate, s); +}; +``` + + + + +#### Map Operation + +We may want to change all the elements of a given set by applying to +them a function. This is called a *map operation*, not to be confused +with the map data structure. + + + + + +In PascaLIGO, the predefined functional iterator implementing the map +operation over sets is called `set_map` and is used as follows: + +```pascaligo group=sets +function increment (const i : int): int is i + 1 + +// Creates a new set with all elements incremented by 1 +const plus_one : set (int) = set_map (increment, larger_set) +``` + + + +In CameLIGO, the predefined functional iterator implementing the map +operation over sets is called `Set.map` and is used as follows: + +```cameligo group=sets +let increment (i : int) : int = i + 1 + +// Creates a new set with all elements incremented by 1 +let plus_one : int set = Set.map increment larger_set +``` + + + +In ReasonLIGO, the predefined functional iterator implementing the map +operation over sets is called `Set.map` and is used as follows: + +```reasonligo group=sets +let increment = (i : int) : int => i + 1; + +// Creates a new set with all elements incremented by 1 +let plus_one : set (int) = Set.map (increment, larger_set); +``` + + +#### Fold Operation + +A *fold operation* is the most general of iterations. The folded +function takes two arguments: an *accumulator* and the structure +*element* at hand, with which it then produces a new accumulator. This +enables having a partial result that becomes complete when the +traversal of the data structure is over. + + + + + +In PascaLIGO, the predefined functional iterator implementing the fold +operation over sets is called `set_fold` and is used as follows: + +```pascaligo group=sets function sum (const acc : int; const i : int): int is acc + i const sum_of_elements : int = set_fold (sum, my_set, 0) ``` - + +> The folded function must be pure, that is, it cannot mutate +> variables. It is possible to use a *loop* over a set as well. - - -```pascaligo group=a +```pascaligo group=sets function loop (const s : set (int)) : int is block { var sum : int := 0; for element in set s block { @@ -471,27 +710,24 @@ function loop (const s : set (int)) : int is block { } } with sum ``` - + + In CameLIGO, the predefined fold over sets is called `Set.fold`. - - -```cameligo group=a +```cameligo group=sets let sum (acc, i : int * int) : int = acc + i let sum_of_elements : int = Set.fold sum my_set 0 ``` - + + In ReasonLIGO, the predefined fold over sets is called `Set.fold`. - - -```reasonligo group=a +```reasonligo group=sets let sum = ((acc, i) : (int, int)) : int => acc + i; let sum_of_elements : int = Set.fold (sum, my_set, 0); ``` - diff --git a/gitlab-pages/docs/language-basics/strings.md b/gitlab-pages/docs/language-basics/strings.md index 297edee09..3ad0d568d 100644 --- a/gitlab-pages/docs/language-basics/strings.md +++ b/gitlab-pages/docs/language-basics/strings.md @@ -6,7 +6,7 @@ title: Strings Strings are defined using the built-in `string` type like this: - + ``` const a : string = "Hello Alice" ``` @@ -21,10 +21,10 @@ let a : string = "Hello Alice"; -## Concatenating strings +## Concatenating Strings - + Strings can be concatenated using the `^` operator. ```pascaligo @@ -51,12 +51,12 @@ let full_greeting : string = greeting ++ " " ++ name; -## Slicing strings +## Slicing Strings Strings can be sliced using a built-in function: - + ```pascaligo const name : string = "Alice" const slice : string = string_slice (0n, 1n, name) @@ -73,29 +73,27 @@ let slice : string = String.slice (0n, 1n, name); ``` -> ⚠️ Notice that the `offset` and slice `length` are natural numbers -> (`nat`). +> ⚠️ Notice that the offset and length of the slice are natural numbers. -## Aquiring the length of a string +## Length of Strings The length of a string can be found using a built-in function: - + ```pascaligo const name : string = "Alice" -// length = 5 -const length : nat = size (name) +const length : nat = size (name) // length = 5 ``` ```cameligo let name : string = "Alice" -let length : nat = String.size name +let length : nat = String.size name // length = 5 ``` ```reasonligo let name : string = "Alice"; -let length : nat = String.size (name); +let length : nat = String.size (name); // length == 5 ``` diff --git a/gitlab-pages/docs/language-basics/tezos-specific.md b/gitlab-pages/docs/language-basics/tezos-specific.md index a1f8c17dc..bd50a4229 100644 --- a/gitlab-pages/docs/language-basics/tezos-specific.md +++ b/gitlab-pages/docs/language-basics/tezos-specific.md @@ -7,7 +7,7 @@ LIGO is a programming language for writing Tezos smart contracts. It would be a little odd if it did not have any Tezos specific functions. This page will tell you about them. -## Pack and unpack +## Pack and Unpack Michelson provides the `PACK` and `UNPACK` instructions for data serialization. The instruction `PACK` converts Michelson data @@ -59,11 +59,12 @@ predefined function returning a value of type `key_hash`. ```pascaligo group=b -function check_hash_key (const kh1 : key_hash; const k2 : key) : bool * key_hash is block { - var ret : bool := False; - var kh2 : key_hash := crypto_hash_key (k2); - if kh1 = kh2 then ret := True else skip -} with (ret, kh2) +function check_hash_key (const kh1 : key_hash; const k2 : key) : bool * key_hash is + block { + var ret : bool := False; + var kh2 : key_hash := crypto_hash_key (k2); + if kh1 = kh2 then ret := True else skip + } with (ret, kh2) ``` @@ -122,14 +123,14 @@ let check_signature = -## Getting the contract's own address +## Contract's Own Address Often you want to get the address of the contract being executed. You can do it with `self_address`. > ⚠️ Due to limitations in Michelson, `self_address` in a contract is -> only allowed at the entry-point level (a.k.a top-level). Using it in -> an auxiliaru function will cause an error. +> only allowed at the entrypoint level, that is, at the +> top-level. Using it in an embedded function will cause an error. diff --git a/gitlab-pages/docs/language-basics/types.md b/gitlab-pages/docs/language-basics/types.md index 6654e7a3b..ace3e8794 100644 --- a/gitlab-pages/docs/language-basics/types.md +++ b/gitlab-pages/docs/language-basics/types.md @@ -3,10 +3,10 @@ id: types title: Types --- -LIGO is strongly and statically typed. This means that the compiler -checks your program at compilation time and, if it passes the tests, -this ensures that there will be no runtime error due to wrong -assumptions on the data. This is called *type checking*. +*LIGO is strongly and statically typed.* This means that the compiler +checks how your contract processes data. If it passes the test, your +contract will not fail at run-time due to inconsistent assumptions on +your data. This is called *type checking*. LIGO types are built on top of Michelson's type system. @@ -23,7 +23,7 @@ alias a string type as an animal breed - this will allow us to comunicate our intent with added clarity. - + ```pascaligo group=a type breed is string const dog_breed : breed = "Saluki" @@ -51,15 +51,14 @@ let dog_breed : breed = "Saluki"; ## Simple types - + ```pascaligo group=b // The type accountBalances denotes maps from addresses to tez type account_balances is map (address, tez) const ledger : account_balances = - map - [("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx" : address) -> 10mutez] + map [("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx" : address) -> 10mutez] ``` @@ -99,19 +98,22 @@ below you can see the definition of data types for a ledger that keeps the balance and number of previous transactions for a given account. - + ```pascaligo group=c // Type aliasing + type account is address type number_of_transactions is nat // The type account_data is a record with two fields. + type account_data is record [ balance : tez; transactions : number_of_transactions ] // A ledger is a map from accounts to account_data + type ledger is map (account, account_data) const my_ledger : ledger = map [ @@ -126,14 +128,19 @@ const my_ledger : ledger = map [ ```cameligo group=c // Type aliasing + type account = address type number_of_transactions = nat + // The type account_data is a record with two fields. + type account_data = { balance : tez; transactions : number_of_transactions } + // A ledger is a map from accounts to account_data + type ledger = (account, account_data) map let my_ledger : ledger = Map.literal @@ -144,16 +151,19 @@ let my_ledger : ledger = Map.literal ```reasonligo group=c // Type aliasing + type account = address; type number_of_transactions = nat; // The type account_data is a record with two fields. + type account_data = { balance : tez, transactions : number_of_transactions }; // A ledger is a map from accounts to account_data + type ledger = map (account, account_data); let my_ledger : ledger = @@ -173,19 +183,91 @@ exclusive to each other). ## Annotations In certain cases, the type of an expression cannot be properly -inferred by the compiler. In order to help the type checke, you can +inferred by the compiler. In order to help the type checker, you can annotate an expression with its desired type. Here is an example: - -```pascaligo -type int_map is map (int, int) -function get_first (const my_map : int_map): option (int) is my_map[1] + +```pascaligo group=d +type parameter is Back | Claim | Withdraw -// The empty map always needs a type annotation +type storage is + record + owner : address; + goal : tez; + deadline : timestamp; + backers : map (address, tez); + funded : bool + end -const first : option (int) = get_first (((map end) : int_map)) +type return is list (operation) * storage + +function back (var action : unit; var store : storage) : return is + begin + if now > store.deadline then + failwith ("Deadline passed.") + else case store.backers[sender] of + None -> store.backers[sender] := amount + | Some (x) -> skip + end + end with ((nil : list (operation)), store) // Annotation +``` + + +```cameligo group=d +type parameter = Back | Claim | Withdraw + +type storage = { + owner : address; + goal : tez; + deadline : timestamp; + backers : (address, tez) map; + funded : bool +} + +type return = operation list * storage + +let back (param, store : unit * storage) : return = + let no_op : operation list = [] in + if Current.time > store.deadline then + (failwith "Deadline passed." : return) // Annotation + else + match Map.find_opt sender store.backers with + None -> + let backers = Map.update sender (Some amount) store.backers + in no_op, {store with backers=backers} + | Some (x) -> no_op, store +``` + + +```reasonligo group=d +type parameter = | Back | Claim | Withdraw; + +type storage = { + owner : address, + goal : tez, + deadline : timestamp, + backers : map (address, tez), + funded : bool, +}; + +type return = (list (operation), storage); + +let back = ((param, store) : (unit, storage)) : return => { + let no_op : list (operation) = []; + if (Current.time > store.deadline) { + (failwith ("Deadline passed.") : return); // Annotation + } + else { + switch (Map.find_opt (sender, store.backers)) { + | None => { + let backers = Map.update (sender, Some (amount), store.backers); + (no_op, {...store, backers:backers}) } + | Some (x) => (no_op, store) + } + } +}; ``` diff --git a/gitlab-pages/docs/language-basics/unit-option-pattern-matching.md b/gitlab-pages/docs/language-basics/unit-option-pattern-matching.md index 3243750cc..ff497a6b3 100644 --- a/gitlab-pages/docs/language-basics/unit-option-pattern-matching.md +++ b/gitlab-pages/docs/language-basics/unit-option-pattern-matching.md @@ -10,21 +10,18 @@ features it as well. Both the option type and the unit types are instances of a more general kind of types: *variant types* (sometimes called *sum types*). -## The unit type +## The unit Type The `unit` type in Michelson or LIGO is a predefined type that contains only one value that carries no information. It is used when no relevant information is required or produced. Here is how it used. -> 💡 Units come in handy when we try pattern matching on custom -> variants below. - - + In PascaLIGO, the unique value of the `unit` type is `Unit`. ```pascaligo group=a -const n : unit = Unit +const n : unit = Unit // Note the capital letter ``` @@ -56,11 +53,11 @@ Here is how we define a coin as being either head or tail (and nothing else): - + ```pascaligo group=b type coin is Head | Tail -const head : coin = Head (Unit) // Unit needed because of a bug -const tail : coin = Tail (Unit) // Unit needed because of a bug +const head : coin = Head (Unit) // Unit needed for now. +const tail : coin = Tail (Unit) // Unit needed for now. ``` @@ -87,7 +84,7 @@ define different kinds of users of a system. - + ```pascaligo group=c type id is nat @@ -128,9 +125,6 @@ let g : user = Guest; -Defining a variant can be extremely useful for building semantically -appealing contracts. We will learn how to use variants for "logic -purposes"' shortly. ## Optional values @@ -143,7 +137,7 @@ meaningful value *of any type*. An example in arithmetic is the division operation: - + ```pascaligo group=d function div (const a : nat; const b : nat) : option (nat) is if b = 0n then (None: option (nat)) else Some (a/b) @@ -169,10 +163,10 @@ let div = ((a, b) : (nat, nat)) : option (nat) => *Pattern matching* is similiar to the `switch` construct in Javascript, and can be used to route the program's control flow based on the value of a variant. Consider for example the definition of a -function `flip` that flips a coin, as defined above. +function `flip` that flips a coin. - + ```pascaligo group=e type coin is Head | Tail diff --git a/gitlab-pages/docs/language-basics/variables-and-constants.md b/gitlab-pages/docs/language-basics/variables-and-constants.md index 87f2ab109..5c3c4ede2 100644 --- a/gitlab-pages/docs/language-basics/variables-and-constants.md +++ b/gitlab-pages/docs/language-basics/variables-and-constants.md @@ -13,7 +13,7 @@ declaration. When defining a constant you need to provide a `name`, `type` and a `value`: - + ```pascaligo group=a const age : int = 25 ``` @@ -53,14 +53,11 @@ ligo evaluate-value gitlab-pages/docs/language-basics/src/variables-and-constant ## Variables - + -Variables, unlike constants, are mutable. They cannot be declared in a -*global scope*, but they can be declared and used within functions, or -as function parameters. - -> 💡 Do not worry if you do not understand the function syntax yet. We -> will get to it in upcoming sections of this documentation. +Variables, unlike constants, are *mutable*. They cannot be declared in +a *global scope*, but they can be declared and used within functions, +or as function parameters. > ⚠️ Please be wary that mutation only works within the function scope > itself, values outside of the function scope will not be affected. @@ -68,7 +65,7 @@ as function parameters. ```pascaligo group=b // The following is invalid: use `const` for global values instead. -// var four : int = 4 +// var four : int := 4 function add (const a : int; const b : int) : int is block { @@ -90,11 +87,8 @@ ligo run-function gitlab-pages/docs/language-basics/src/variables-and-constants/ As expected in the pure subset of a functional language, CameLIGO only -features constant values: once they are declared, the value cannot be -changed (or "mutated"). - -> 💡 Do not worry if you do not understand the function syntax yet. We -> will get to it in upcoming sections of this documentation. +features *constant values*: once they are declared, the value cannot +be changed (or "mutated"). ```cameligo group=c let add (a : int) (b : int) : int = @@ -110,12 +104,9 @@ ligo run-function gitlab-pages/docs/language-basics/src/variables-and-constants/ As expected in the pure subset of a functional language, ReasonLIGO -only features constant values: once they are declared, the value +only features *constant values*: once they are declared, the value cannot be changed (or "mutated"). -> 💡 Do not worry if you do not understand the function syntax yet. We -> will get to it in upcoming sections of this documentation. - ```reasonligo group=c let add = ((a, b): (int, int)): int => { let c : int = a + b; diff --git a/gitlab-pages/website/core/CodeExamples.js b/gitlab-pages/website/core/CodeExamples.js index 4ace23b4e..9cdf27c1c 100644 --- a/gitlab-pages/website/core/CodeExamples.js +++ b/gitlab-pages/website/core/CodeExamples.js @@ -3,68 +3,83 @@ const React = require('react'); const pre = '```'; const PASCALIGO_EXAMPLE = `${pre}pascaligo -// variant defining pseudo multi-entrypoint actions -type action is -| Increment of int +type storage is int + +type parameter is + Increment of int | Decrement of int +| Reset -function add (const a : int ; const b : int) : int is a + b +type return is list (operation) * storage -function subtract (const a : int ; const b : int) : int is a - b +// Two entrypoints -// real entrypoint that re-routes the flow based on the action provided -function main (const p : action ; const s : int) : (list(operation) * int) is - ((nil : list(operation)), - case p of - | Increment (n) -> add (s, n) - | Decrement (n) -> subtract (s, n) - end) +function add (const store : storage; const delta : int) : storage is store + delta +function sub (const store : storage; const delta : int) : storage is store - delta + +(* Main access point that dispatches to the entrypoints according to + the smart contract parameter. *) + +function main (const action : parameter; const store : storage) : return is + ((nil : list (operation)), // No operations + case action of + Increment (n) -> add (store, n) + | Decrement (n) -> sub (store, n) + | Reset -> 0 + end) ${pre}`; const CAMELIGO_EXAMPLE = `${pre}ocaml type storage = int -(* variant defining pseudo multi-entrypoint actions *) - -type action = -| Increment of int +type parameter = + Increment of int | Decrement of int +| Reset -let add (a,b: int * int) : int = a + b -let sub (a,b: int * int) : int = a - b +type return = operation list * storage -(* real entrypoint that re-routes the flow based on the action provided *) +// Two entrypoints -let main (p,s: action * storage) = - let storage = - match p with - | Increment n -> add (s, n) - | Decrement n -> sub (s, n) - in ([] : operation list), storage +let add (store, delta : storage * int) : storage = store + delta +let sub (store, delta : storage * int) : storage = store - delta + +(* Main access point that dispatches to the entrypoints according to + the smart contract parameter. *) + +let main (action, store : parameter * storage) : return = + ([] : operation list), // No operations + (match action with + Increment (n) -> add (store, n) + | Decrement (n) -> sub (store, n) + | Reset -> 0) ${pre}`; const REASONLIGO_EXAMPLE = `${pre}reasonligo type storage = int; -/* variant defining pseudo multi-entrypoint actions */ +type parameter = + Increment (int) +| Decrement (int) +| Reset; -type action = - | Increment(int) - | Decrement(int); +type return = (list (operation), storage); -let add = ((a,b): (int, int)): int => a + b; -let sub = ((a,b): (int, int)): int => a - b; +(* Two entrypoints *) -/* real entrypoint that re-routes the flow based on the action provided */ +let add = ((store, delta) : (storage, int)) : storage => store + delta; +let sub = ((store, delta) : (storage, int)) : storage => store - delta; -let main = ((p,storage): (action, storage)) => { - let storage = - switch (p) { - | Increment(n) => add((storage, n)) - | Decrement(n) => sub((storage, n)) - }; - ([]: list(operation), storage); +(* Main access point that dispatches to the entrypoints according to + the smart contract parameter. *) + +let main = ((action, store) : (parameter, storage)) : return => { + (([] : list (operation)), // No operations + (switch (action) { + | Increment (n) => add ((store, n)) + | Decrement (n) => sub ((store, n)) + | Reset => 0})) }; ${pre}`; diff --git a/gitlab-pages/website/pages/en/index.js b/gitlab-pages/website/pages/en/index.js index a9bc41277..9bbddcb17 100644 --- a/gitlab-pages/website/pages/en/index.js +++ b/gitlab-pages/website/pages/en/index.js @@ -6,14 +6,14 @@ const docUrl = require(`${process.cwd()}/core/UrlUtils`).docUrl; const FEATURES = [ { image: 'img/strong-type-system.svg', - title: 'Strong Type System', + title: 'Strong, Static Type System', content: 'Write types, then code. Benefit from the safety of type systems.' }, { image: 'img/syntax-agnostic.svg', - title: 'Syntax Agnostic', + title: 'Polyglot', content: - 'Code in your language. Write PascaLIGO, CameLIGO, or add your own syntax.' + 'Code in your language. Write PascaLIGO, CameLIGO, ReasonLIGO or add your own syntax.' }, { image: 'img/easy-integration.svg', @@ -77,7 +77,7 @@ module.exports = props => {
-

A friendly smart-contract language for Tezos

+

A friendly Smart Contract Language for Tezos

Michelson was never so easy

diff --git a/gitlab-pages/website/siteConfig.js b/gitlab-pages/website/siteConfig.js index c42f07a31..b0f7d419c 100644 --- a/gitlab-pages/website/siteConfig.js +++ b/gitlab-pages/website/siteConfig.js @@ -4,7 +4,7 @@ let reasonHighlightJs = require('reason-highlightjs'); const siteConfig = { title: 'LIGO', // Title for your website. - tagline: 'LIGO is a friendly smart-contract language for Tezos', + tagline: 'LIGO, the friendly Smart Contract Language for Tezos', taglineSub: 'Michelson was never so easy', url: 'https://ligolang.org', // Your website URL baseUrl: '/', // Base URL for your project */ @@ -14,7 +14,7 @@ const siteConfig = { // Used for publishing and more projectName: 'ligo', - organizationName: 'marigold', + organizationName: 'TBN', // For top-level user or org sites, the organization is still the same. // e.g., for the https://JoelMarcey.github.io site, it would be set like... // organizationName: 'JoelMarcey' @@ -87,10 +87,11 @@ const siteConfig = { beginKeywords: '', keywords: { keyword: - 'and begin block case const contains down else end fail for ' + - 'from function if in is list map mod nil not of or patch ' + - 'procedure record remove set skip step then to type var while with', - literal: 'true false unit int string some none bool nat list' + 'and attributes begin big_map block case const contains else' + + ' end False for from function if in is list map mod nil' + + ' not of or patch record remove set skip then to True type' + + ' var while with', + literal: 'true false unit int string Some None bool nat list' }, lexemes: '[a-zA-Z][a-zA-Z0-9_]*', contains: [ diff --git a/gitlab-pages/website/versioned_docs/version-next/contributors/origin.md b/gitlab-pages/website/versioned_docs/version-next/contributors/origin.md index 3b3820ef0..805f45c40 100644 --- a/gitlab-pages/website/versioned_docs/version-next/contributors/origin.md +++ b/gitlab-pages/website/versioned_docs/version-next/contributors/origin.md @@ -4,8 +4,8 @@ title: Origin original_id: origin --- -LIGO is a programming language that aims to provide developers with an uncomplicated and safer way to implement smart-contracts. LIGO is currently being implemented for the Tezos blockchain and as a result, it compiles down to Michelson - the native smart-contract language of Tezos. +LIGO is a programming language that aims to provide developers with an uncomplicated and safe way to implement smart-contracts. Since it is being implemented for the Tezos blockchain LIGO compiles to Michelson—the native smart-contract language of Tezos. > Smart-contracts are programs that run within a blockchain network. -LIGO was initially meant to be a language for developing Marigold, on top of a hacky framework called Meta-Michelson. However, due to the attention received by the Tezos community, a decision has been put into action to develop LIGO as a standalone language that will support Tezos directly as well. \ No newline at end of file +LIGO was meant to be a language for developing Marigold on top of a hacky framework called Meta-Michelson. However, due to the attention received by the Tezos community, LIGO is now a standalone language being developed to support Tezos directly. \ No newline at end of file diff --git a/gitlab-pages/website/versioned_docs/version-next/contributors/philosophy.md b/gitlab-pages/website/versioned_docs/version-next/contributors/philosophy.md index 349c6d131..1d2dc2e3c 100644 --- a/gitlab-pages/website/versioned_docs/version-next/contributors/philosophy.md +++ b/gitlab-pages/website/versioned_docs/version-next/contributors/philosophy.md @@ -4,23 +4,22 @@ title: Philosophy original_id: philosophy --- -To understand LIGO’s design choices, it’s important to get its philosophy. There are two main concerns that we have in mind when building LIGO. - - +To understand LIGO’s design choices it’s important to understand its philosophy. We have two main concerns in mind while building LIGO. ## Safety Once a smart-contract is deployed, it will likely be impossible to change it. You must get it right on the first try, and LIGO should help as much as possible. There are multiple ways to make LIGO a safer language for smart-contracts. ### Automated Testing -Automated Testing is the process through which a program will run some other program, and check that this other program behaves correctly. +Automated Testing is the process through which a program runs another program, and checks that this other program behaves correctly. + There already is a testing library for LIGO programs written in OCaml that is used to test LIGO itself. Making it accessible to users will greatly improve safety. A way to do so would be to make it accessible from within LIGO. ### Static Analysis Static analysis is the process of having a program analyze another one. -For instance, type systems are a kind of static analysis through which it is possible to find lots of bugs. There is already a fairly simple type system in LIGO, and we plan to make it much stronger. +For instance, type systems are a kind of static analysis through which it is possible to find lots of bugs. LIGO already has a simple type system, and we plan to make it much stronger. ### Conciseness -Writing less code gives you less room to introduce errors and that's why LIGO encourages writing lean rather than chunky smart-contracts. +Writing less code gives you less room to introduce errors. That's why LIGO encourages writing lean rather than chunky smart-contracts. --- diff --git a/gitlab-pages/website/versioned_sidebars/version-next-sidebars.json b/gitlab-pages/website/versioned_sidebars/version-next-sidebars.json index e74ff6d36..07fc287dd 100644 --- a/gitlab-pages/website/versioned_sidebars/version-next-sidebars.json +++ b/gitlab-pages/website/versioned_sidebars/version-next-sidebars.json @@ -6,15 +6,27 @@ "version-next-intro/editor-support" ], "Language Basics": [ - "version-next-language-basics/cheat-sheet", "version-next-language-basics/types", - "version-next-language-basics/variables", + "version-next-language-basics/constants-and-variables", + "version-next-language-basics/math-numbers-tez", + "version-next-language-basics/strings", "version-next-language-basics/functions", - "version-next-language-basics/entrypoints", - "version-next-language-basics/operators" + "version-next-language-basics/boolean-if-else", + "version-next-language-basics/loops", + "version-next-language-basics/unit-option-pattern-matching", + "version-next-language-basics/maps-records", + "version-next-language-basics/sets-lists-tuples", + "version-next-language-basics/tezos-specific" + ], + "Advanced": [ + "version-next-advanced/timestamps-addresses", + "version-next-advanced/entrypoints-contracts", + "version-next-advanced/include", + "version-next-advanced/first-contract" ], "API": [ - "version-next-api-cli-commands" + "version-next-api/cli-commands", + "version-next-api/cheat-sheet" ] }, "version-next-contributors-docs": { diff --git a/src/passes/operators/operators.ml b/src/passes/operators/operators.ml index be1196ad1..42aa97936 100644 --- a/src/passes/operators/operators.ml +++ b/src/passes/operators/operators.ml @@ -32,7 +32,7 @@ module Simplify = struct - The left-hand-side is the reserved name in the given front-end. - The right-hand-side is the name that will be used in the AST. *) - let unit_expr = make_t @@ T_constant TC_unit + let unit_expr = make_t @@ T_constant TC_unit let type_constants s = match s with @@ -185,6 +185,7 @@ module Simplify = struct | "Set.literal" -> ok C_SET_LITERAL | "Set.add" -> ok C_SET_ADD | "Set.remove" -> ok C_SET_REMOVE + | "Set.iter" -> ok C_SET_ITER | "Set.fold" -> ok C_SET_FOLD | "Set.size" -> ok C_SIZE @@ -1152,7 +1153,7 @@ module Compiler = struct | C_CONCAT -> ok @@ simple_binary @@ prim I_CONCAT | C_CHAIN_ID -> ok @@ simple_constant @@ prim I_CHAIN_ID | _ -> simple_fail @@ Format.asprintf "operator not implemented for %a" Stage_common.PP.constant c - + (* Some complex operators will need to be added in compiler/compiler_program.