Let return take 0 arguments

Fixes #53. Also added an argument number sanity-check to the `return` macro's implementation, and an additional test for it firing.
anko · Jul 30, 2017 · 859e19e · 859e19e
1 parent c483d59
commit 859e19e
Show file tree

Hide file tree

Showing 2 changed files with 12 additions and 1 deletion.
diff --git a/src/built-in-macros.ls b/src/built-in-macros.ls
@@ -283,8 +283,11 @@ contents =
     body  : body
 
   \return : (arg) ->
+    if &length not in [ 0 1 ]
+      throw Error "Expected `return` macro to get 0 or 1 arguments, but got \
+                   #{&length}"
     type : \ReturnStatement
-    argument : @compile arg
+    argument : if arg then @compile arg else null
 
   \. : do
 

diff --git a/test.ls b/test.ls
@@ -253,6 +253,14 @@ test "return statement" ->
   esl "(lambda () (return \"hello there\"))"
     ..`@equals` "(function () {\n    return 'hello there';\n});"
 
+test "empty return statement" ->
+  esl "(lambda () (return))"
+    ..`@equals` "(function () {\n    return;\n});"
+
+test "return with too many args throws" ->
+  (-> esl "(lambda () (return 1 2))")
+    ..`@throws` Error
+
 test "member expression" ->
   esl "(. console log)"
     ..`@equals` "console.log;"