Implemented append.

Author: artob

README.md

@@ -335,7 +335,7 @@ Feature | Type | Status | Notes
 `>` | function | ✅ |
 `>=` | function | ✅ |
 `and` | operator | ✅ | For two parameters.
-`append` | function | 🚧 |
+`append` | function | ✅ |
 `as-contract` | operator | 🚧 |
 `as-max-len?` | operator | 🚧 |
 `asserts!` | function | ✅ |

lib/Clar2EVM/compile.ml

@@ -262,7 +262,7 @@ and compile_expression env = function
     end
 
   | ListExpression xs ->
-    List.rev (List.concat_map (compile_expression env) xs) @ [EVM.from_int (List.length xs)]
+    List.concat_map (compile_expression env) xs @ [EVM.from_int (List.length xs)]
 
   | Lt (a, b) ->
     let a = compile_expression env a in
@@ -386,6 +386,15 @@ and compile_expression env = function
   | Keyword "stx-liquid-supply" -> unsupported "stx-liquid-supply"
   | Keyword "tx-sender" -> EVM.origin
 
+  | FunctionCall ("append", [list; element]) ->
+    begin match type_of_expression list, type_of_expression element with
+    | List (n, e1), e2 when e1 = e2 ->
+      let list = compile_expression env list in
+      let element = compile_expression env element in
+      list @ EVM.pop1 @ element @ [EVM.from_int (n + 1)]
+    | t, e -> unsupported_function2 "append" t e
+    end
+
   | FunctionCall ("asserts!", [bool_expr; _]) ->  (* TODO: thrown_value *)
     begin match type_of_expression bool_expr with
     | Bool ->

lib/Clar2EVM/typecheck.ml

@@ -56,6 +56,12 @@ let rec type_of_expression = function
   | Keyword "tx-sender" -> Principal
   | Keyword id -> unimplemented (Printf.sprintf "type_of_expression for %s" id)
 
+  | FunctionCall ("append", [list; element]) ->
+    begin match type_of_expression list, type_of_expression element with
+    | List (n, e1), e2 when e1 = e2 -> List (n + 1, e1)
+    | t, e -> unsupported_function2 "append" t e
+    end
+
   | FunctionCall ("get", [_; tuple]) -> type_of_expression tuple
   | FunctionCall ("hash160", _) -> Buff 20
   | FunctionCall ("keccak256", _) -> Buff 32

test/functions.t

@@ -60,6 +60,12 @@ https://docs.blockstack.org/references/language-functions
 
 append:
 
+  $ clarc -t opcode -f only-function=test <<EOF
+  > (define-read-only (test) (append (list 5 6 7) 8))
+  > EOF
+  PUSH1 0x05 PUSH1 0x06 PUSH1 0x07 PUSH1 0x03 POP PUSH1 0x08 PUSH1 0x04
+  PUSH1 0x00 MSTORE PUSH1 0x20 PUSH1 0x00 RETURN STOP
+
 asserts!:
 
   $ clarc -t opcode -f only-function=test <<EOF
@@ -313,7 +319,7 @@ list:
   $ clarc -t opcode -f only-function=test <<EOF
   > (define-read-only (test) (list 1 2 3))
   > EOF
-  PUSH1 0x03 PUSH1 0x02 PUSH1 0x01 PUSH1 0x03 PUSH1 0x00 MSTORE PUSH1 0x20
+  PUSH1 0x01 PUSH1 0x02 PUSH1 0x03 PUSH1 0x03 PUSH1 0x00 MSTORE PUSH1 0x20
   PUSH1 0x00 RETURN STOP
 
 map: