Big_map: first example of syntax specific titles.

This commit is contained in:
Sander Spies 2020-03-09 18:20:21 +01:00
parent 6da6fc2e59
commit 19848c2f67

View File

@ -1,25 +1,36 @@
---
id: big-map-reference
title: Big Maps — Scalable Maps
title: Big_map
description: A lazily deserialized map that's intended to store large amounts of data.
hide_table_of_contents: true
---
import Syntax from '@theme/Syntax';
import SyntaxTitle from '@theme/SyntaxTitle';
Ordinary maps are fine for contracts with a finite lifespan or a
bounded number of users. For many contracts however, the intention is
to have a map holding *many* entries, potentially millions of
them. The cost of loading those entries into the environment each time
a user executes the contract would eventually become too expensive
were it not for *big maps*. Big maps are a data structure offered by
Michelson which handles the scaling concerns for us. In LIGO, the
interface for big maps is analogous to the one used for ordinary maps.
A lazily deserialized map that's intended to store large amounts of data.
# Declaring a Map
The gast costs of deserialized maps are higher than standard maps as data is lazily deserialized.
<SyntaxTitle syntax="pascaligo">
type big_map (key, value)
</SyntaxTitle>
<SyntaxTitle syntax="cameligo">
type ('key, 'value) big_map
</SyntaxTitle>
<SyntaxTitle syntax="reasonligo">
type big_map ('key, 'value)
</SyntaxTitle>
<Syntax syntax="pascaligo">
```pascaligo group=big_maps
The type of a big map from values of type `key` to
values of type `value` is `big_map (key, value)`.
```pascaligo group=big_map
type move is int * int
type register is big_map (address, move)
```
@ -27,57 +38,91 @@ type register is big_map (address, move)
</Syntax>
<Syntax syntax="cameligo">
```cameligo group=big_maps
The type of a big map from values of type `key` to values
of type `value` is `(key, value) big_map`.
```cameligo group=big_map
type move = int * int
type register = (address, move) big_map
```
</Syntax>
<Syntax syntax="reasonligo">
The type of a big map from values of type `key` to
values of type `value` is `big_map (key, value)`.
```reasonligo group=big_maps
```reasonligo group=big_map
type move = (int, int);
type register = big_map (address, move);
```
</Syntax>
<SyntaxTitle syntax="pascaligo">
function empty : big_map (key, value)
</SyntaxTitle>
<SyntaxTitle syntax="cameligo">
val empty : ('key, 'value) big_map
</SyntaxTitle>
<SyntaxTitle syntax="reasonligo">
let empty: big_map ('key, 'value)
</SyntaxTitle>
# Creating an Empty Big Map
Create an empty big_map.
<Syntax syntax="pascaligo">
```pascaligo group=big_maps
```pascaligo group=big_map
const empty : register = Big_map.empty
```
Alternatively, you can also create an empty big_map using:
```pascaligo group=big_map
const empty : register = big_map []
```
</Syntax>
<Syntax syntax="cameligo">
```cameligo group=big_maps
```cameligo group=big_map
let empty : register = Big_map.empty
```
</Syntax>
<Syntax syntax="reasonligo">
```reasonligo group=big_maps
```reasonligo group=big_map
let empty : register = Big_map.empty
```
</Syntax>
# Creating a Non-empty Map
<SyntaxTitle syntax="pascaligo">
function literal : list (key * value) -> big_map (key, value)
</SyntaxTitle>
<SyntaxTitle syntax="cameligo">
val literal : ('key * 'value) list -> ('key, 'value) big_map
</SyntaxTitle>
<SyntaxTitle syntax="reasonligo">
let literal: list(('key, 'value)) => big_map('key, 'value)
</SyntaxTitle>
Create a non-empty big_map.
<Syntax syntax="pascaligo">
```pascaligo group=big_maps
```pascaligo group=big_map
const moves : register =
Big_map.literal ([
("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx" : address) -> (1,2);
("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address) -> (0,3)])
```
Alternative way of creating an empty big_map:
```pascaligo group=big_map
const moves : register =
big_map [
("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx" : address) -> (1,2);
@ -87,7 +132,7 @@ const moves : register =
</Syntax>
<Syntax syntax="cameligo">
```cameligo group=big_maps
```cameligo group=big_map
let moves : register =
Big_map.literal [
(("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx" : address), (1,2));
@ -97,7 +142,7 @@ let moves : register =
</Syntax>
<Syntax syntax="reasonligo">
```reasonligo group=big_maps
```reasonligo group=big_map
let moves : register =
Big_map.literal ([
("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx" : address, (1,2)),
@ -106,13 +151,32 @@ let moves : register =
</Syntax>
<SyntaxTitle syntax="pascaligo">
function find_opt : key -> big_map (key, value) -> option value
</SyntaxTitle>
<SyntaxTitle syntax="cameligo">
val find_opt : 'key -> ('key, 'value) big_map -> 'value option
</SyntaxTitle>
<SyntaxTitle syntax="reasonligo">
let find_opt : ('key, big_map ('key, 'value)) => option ('value)
</SyntaxTitle>
# Accessing Values
Retrieve a value from a big map with the given key.
Because the key may be missing in the big map, the result is an
*optional value*.
<Syntax syntax="pascaligo">
```pascaligo group=big_maps
```pascaligo group=big_map
const my_balance : option (move) =
Big_map.find_opt ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address, moves)
```
Alternatively:
```pascaligo group=big_map
const my_balance : option (move) =
moves [("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address)]
```
@ -120,7 +184,7 @@ const my_balance : option (move) =
</Syntax>
<Syntax syntax="cameligo">
```cameligo group=big_maps
```cameligo group=big_map
let my_balance : move option =
Big_map.find_opt ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address) moves
```
@ -128,33 +192,57 @@ let my_balance : move option =
</Syntax>
<Syntax syntax="reasonligo">
```reasonligo group=big_maps
```reasonligo group=big_map
let my_balance : option (move) =
Big_map.find_opt ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address, moves);
```
</Syntax>
<SyntaxTitle syntax="pascaligo">
function update : key -> option value -> big_map (key, value) -> big_map (key, value)
</SyntaxTitle>
<SyntaxTitle syntax="cameligo">
val update: 'key -> 'value option -> ('key, 'value) big_map -> ('key, 'value) big_map
</SyntaxTitle>
<SyntaxTitle syntax="reasonligo">
let update: ('key, option('value), big_map ('key, 'value)) => big_map ('key, 'value)
</SyntaxTitle>
# Updating Big Maps
Note: when `None` is used as a value, the value is removed from the big_map.
<Syntax syntax="pascaligo">
```pascaligo group=big_maps
function add (var m : register) : register is
block {
m [("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address)] := (4,9)
} with m
const updated_map : register = add (moves)
```pascaligo group=big_map
Big_map.update(("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address), m, (4,9));
```
Alternatively:
```pascaligo group=big_map
m [("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address)] := (4,9)
```
If multiple bindings need to be updated, PascaLIGO offers a *patch
instruction* for maps, similar to that for records.
```pascaligo group=big_map
function assignments (var m : register) : register is
block {
patch m with map [
("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address) -> (4,9);
("tz1KqTpEZ7Yob7QbPE4Hy4Wo8fHG8LhKxZSx" : address) -> (1,2)
]
} with m
```
> Note the use of the keyword `map` instead of `big_map` (which is not
> a keyword).
</Syntax>
<Syntax syntax="cameligo">
```cameligo group=big_maps
```cameligo group=big_map
let updated_map : register =
Big_map.update
("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address) (Some (4,9)) moves
@ -163,7 +251,7 @@ let updated_map : register =
</Syntax>
<Syntax syntax="reasonligo">
```reasonligo group=big_maps
```reasonligo group=big_map
let updated_map : register =
Big_map.update
(("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address), Some ((4,9)), moves);
@ -171,14 +259,64 @@ let updated_map : register =
</Syntax>
<SyntaxTitle syntax="pascaligo">
function add : key -> value -> big_map (key, value) -> big_map (key, value)
</SyntaxTitle>
<SyntaxTitle syntax="cameligo">
val add : 'key -> 'value -> ('key, 'value) big_map -> ('key, 'value) big_map
</SyntaxTitle>
<SyntaxTitle syntax="reasonligo">
let add: ('key, 'value, big_map('key, 'value)) => big_map('key, 'value)
</SyntaxTitle>
<Syntax syntax="pascaligo">
# Removing Bindings
```pascaligo group=big_map
Big_map.add (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address), (4, 9), m)
```
</Syntax>
<Syntax syntax="cameligo">
```cameligo group=big_map
let add (m : register) : register =
Big_map.add
("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address) (4,9) m
```
</Syntax>
<Syntax syntax="reasonligo">
```reasonligo group=big_map
let add = (m: register): register =>
Big_map.add
(("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN" : address), (4,9), m);
```
</Syntax>
<SyntaxTitle syntax="pascaligo">
function remove: key -> big_map (key, value) -> big_map (key, value)
</SyntaxTitle>
<SyntaxTitle syntax="cameligo">
val remove: 'key -> ('key, 'value) big_map -> ('key, 'value) big_map
</SyntaxTitle>
<SyntaxTitle syntax="reasonligo">
let remove: (key, big_map ('key, 'value)) => big_map ('key, 'value)
</SyntaxTitle>
<Syntax syntax="pascaligo">
```pascaligo group=big_maps
```pascaligo group=big_map
const_updated_map : register =
Big_map.remove (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address), moves)
```
Alternatively, the instruction `remove key from map m` removes the key
`key` from the big map `m` (note that the keyword is `map`, not
`big_map`).
```pascaligo group=big_map
function rem (var m : register) : register is
block {
remove ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address) from map moves
@ -190,17 +328,17 @@ const updated_map : register = rem (moves)
</Syntax>
<Syntax syntax="cameligo">
```cameligo group=big_maps
```cameligo group=big_map
let updated_map : register =
Map.remove ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address) moves
Big_map.remove ("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address) moves
```
</Syntax>
<Syntax syntax="reasonligo">
```reasonligo group=big_maps
```reasonligo group=big_map
let updated_map : register =
Map.remove (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address), moves)
Big_map.remove (("tz1gjaF81ZRRvdzjobyfVNsAeSC6PScjfQwN": address), moves)
```
</Syntax>