From 0fb37e9d3f08979d63c2df3d7c4ce6b16e4f21ba Mon Sep 17 00:00:00 2001
From: galfour <gabriel.alfour@gmail.com>
Date: Sun, 8 Sep 2019 12:34:29 +0200
Subject: [PATCH] adding list cons

---
 src/contracts/list.ligo       | 4 ++++
 src/operators/operators.ml    | 8 ++++++++
 src/test/integration_tests.ml | 8 ++++++++
 3 files changed, 20 insertions(+)

diff --git a/src/contracts/list.ligo b/src/contracts/list.ligo
index 99920b92a..a533d12e2 100644
--- a/src/contracts/list.ligo
+++ b/src/contracts/list.ligo
@@ -5,6 +5,10 @@ const fb : foobar = list
   42 ;
 end
 
+const fb2 : foobar = 144 # fb
+
+const fb3 : foobar = cons(688 , fb2)
+
 function size_ (const m : foobar) : nat is
   block {skip} with (size(m))
 
diff --git a/src/operators/operators.ml b/src/operators/operators.ml
index cdf983b6a..61495e0e9 100644
--- a/src/operators/operators.ml
+++ b/src/operators/operators.ml
@@ -88,6 +88,7 @@ module Simplify = struct
       ("sha_256" , "SHA256") ;
       ("sha_512" , "SHA512") ;
       ("blake2b" , "BLAKE2b") ;
+      ("cons" , "CONS") ;
     ]
 
     let type_constants = type_constants
@@ -228,6 +229,11 @@ module Typer = struct
 
   let some = typer_1 "SOME" @@ fun a -> ok @@ t_option a ()
 
+  let list_cons : typer = typer_2 "CONS" @@ fun hd tl ->
+    let%bind tl' = get_t_list tl in
+    let%bind () = assert_type_value_eq (hd , tl') in
+    ok tl
+
   let map_remove : typer = typer_2 "MAP_REMOVE" @@ fun k m ->
     let%bind (src , _) = get_t_map m in
     let%bind () = assert_type_value_eq (src , k) in
@@ -617,6 +623,7 @@ module Typer = struct
       slice ;
       address ;
       assertion ;
+      list_cons ;
     ]
 
 end
@@ -691,6 +698,7 @@ module Compiler = struct
     ("HASH_KEY" , simple_unary @@ prim I_HASH_KEY) ;
     ("PACK" , simple_unary @@ prim I_PACK) ;
     ("CONCAT" , simple_binary @@ prim I_CONCAT) ;
+    ("CONS" , simple_binary @@ prim I_CONS) ;
   ]
 
   (* Some complex predicates will need to be added in compiler/compiler_program *)
diff --git a/src/test/integration_tests.ml b/src/test/integration_tests.ml
index 4432f07b9..baea8d256 100644
--- a/src/test/integration_tests.ml
+++ b/src/test/integration_tests.ml
@@ -402,6 +402,14 @@ let list () : unit result =
     let expected = ez [23 ; 42] in
     expect_eq_evaluate program "fb" expected
   in
+  let%bind () =
+    let expected = ez [144 ; 23 ; 42] in
+    expect_eq_evaluate program "fb2" expected
+  in
+  let%bind () =
+    let expected = ez [688 ; 144 ; 23 ; 42] in
+    expect_eq_evaluate program "fb3" expected
+  in
   let%bind () =
     let make_input = fun n -> (ez @@ List.range n) in
     let make_expected = e_nat in