Letrec and letfun (#65)

* Type check and compile letfuns

* Minor code simplification

* Remove let rec from Sophia

test/aeso_compiler_tests.erl

@@ -86,6 +86,7 @@ compilable_contracts() ->
      "dutch_auction",
      "environment",
      "factorial",
+     "functions",
      "fundme",
      "identity",
      "maps",

test/aeso_scan_tests.erl

@@ -41,7 +41,7 @@ all_tokens() ->
     %% Operators
     lists:map(Lit, ['=', '==', '!=', '>', '<', '>=', '=<', '-', '+', '++', '*', '/', mod, ':', '::', '->', '=>', '||', '&&', '!']) ++
     %% Keywords
-    lists:map(Lit, [contract, type, 'let', switch, rec, 'and']) ++
+    lists:map(Lit, [contract, type, 'let', switch]) ++
     %% Comment token (not an actual token), just for tests
     [{comment, 0, "// *Comment!\"\n"},
      {comment, 0, "/* bla /* bla bla */*/"}] ++

test/contracts/all_syntax.aes

@@ -36,11 +36,6 @@ contract AllSyntax =
       (x, [y, z]) => bar({x = z, y = -y + - -z * (-1)})
       (x, y :: _) => ()
 
-  function mutual() =
-    let rec recFun(x : int) = mutFun(x)
-        and mutFun(x) = if(x =< 0) 1 else x * recFun(x - 1)
-    recFun(0)
-
   let hash : address = #01ab0fff11
   let b = false
   let qcon = Mod.Con

test/contracts/functions.aes

@@ -0,0 +1,15 @@
+contract Functions =
+  private function curry(f : ('a, 'b) => 'c) =
+    (x) => (y) => f(x, y)
+  private function map(f : 'a => 'b, xs : list('a)) =
+    switch(xs)
+      [] => []
+      x :: xs => f(x) :: map(f, xs)
+  private function map'() = map
+  private function plus(x, y) = x + y
+  function test1(xs : list(int)) = map(curry(plus)(5), xs)
+  function test2(xs : list(int)) = map'()(((x) => (y) => ((x, y) => x + y)(x, y))(100), xs)
+  function test3(xs : list(int)) =
+    let m(f, xs) = map(f, xs)
+    m((x) => x + 1, xs)
+