From 8e8bb4b9b980b3b9bc660a46f262f522334c9f84 Mon Sep 17 00:00:00 2001
From: Bob Nystrom <robert@stuffwithstuff.com>
Date: Sun, 12 Jan 2014 19:37:11 -0800
Subject: [PATCH] Allow returns without an explicit value.

---
 src/wren_compiler.c                     | 13 +++++++++----
 src/wren_core.c                         |  2 +-
 test/return/in_function.wren            |  7 ++++++-
 test/return/return_null_if_brace.wren   |  6 ++++++
 test/return/return_null_if_newline.wren |  6 ++++++
 5 files changed, 28 insertions(+), 6 deletions(-)
 create mode 100644 test/return/return_null_if_brace.wren
 create mode 100644 test/return/return_null_if_newline.wren

diff --git a/src/wren_compiler.c b/src/wren_compiler.c
index a5f70448..2a67cff8 100644
--- a/src/wren_compiler.c
+++ b/src/wren_compiler.c
@@ -1828,7 +1828,6 @@ void namedSignature(Compiler* compiler, char* name, int* length)
   if (match(compiler, TOKEN_EQ))
   {
     // It's a setter.
-    // TODO: Allow setters with parameters? Like: foo.bar(1, 2) = "blah"
     name[(*length)++] = '=';
     name[(*length)++] = ' ';
 
@@ -2326,9 +2325,15 @@ void statement(Compiler* compiler)
   if (match(compiler, TOKEN_RETURN))
   {
     // Compile the return value.
-    // TODO: Implicitly return null if there is a newline or } after the
-    // "return".
-    expression(compiler);
+    if (peek(compiler) == TOKEN_LINE || peek(compiler) == TOKEN_RIGHT_BRACE)
+    {
+      // Implicitly return null if there is no value.
+      emit(compiler, CODE_NULL);
+    }
+    else
+    {
+      expression(compiler);
+    }
 
     emit(compiler, CODE_RETURN);
     return;
diff --git a/src/wren_core.c b/src/wren_core.c
index c7515ed8..0b9aba1d 100644
--- a/src/wren_core.c
+++ b/src/wren_core.c
@@ -185,7 +185,7 @@ DEF_NATIVE(fiber_create)
 
   ObjFiber* newFiber = wrenNewFiber(vm, AS_OBJ(args[1]));
 
-  // The compiler expect the first slot of a function to hold the receiver.
+  // The compiler expects the first slot of a function to hold the receiver.
   // Since a fiber's stack is invoked directly, it doesn't have one, so put it
   // in here.
   // TODO: Is there a cleaner solution?
diff --git a/test/return/in_function.wren b/test/return/in_function.wren
index 0b1a26af..916d7390 100644
--- a/test/return/in_function.wren
+++ b/test/return/in_function.wren
@@ -1 +1,6 @@
-var a = "ok"; IO.print(a) // expect: ok
+var f = fn {
+  return "ok"
+  IO.print("bad")
+}
+
+IO.print(f.call) // expect: ok
diff --git a/test/return/return_null_if_brace.wren b/test/return/return_null_if_brace.wren
new file mode 100644
index 00000000..31010935
--- /dev/null
+++ b/test/return/return_null_if_brace.wren
@@ -0,0 +1,6 @@
+var f = fn {
+  if (true) { return }
+  IO.print("bad")
+}
+
+IO.print(f.call) // expect: null
diff --git a/test/return/return_null_if_newline.wren b/test/return/return_null_if_newline.wren
new file mode 100644
index 00000000..ab5ad28d
--- /dev/null
+++ b/test/return/return_null_if_newline.wren
@@ -0,0 +1,6 @@
+var f = fn {
+  return
+  IO.print("bad")
+}
+
+IO.print(f.call) // expect: null