Allow return keyword to used as assembly opcode

Author: cgewecke

solidity.pegjs

@@ -1610,8 +1610,18 @@ AssemblyAssignment
     }
   }
 
+ReturnOpCode 
+  = 'return' {
+    return {
+      type: "Identifier",
+      name: "return",
+      start: location().start.offset,
+      end: location().end.offset
+    }
+  }
+
 FunctionalAssemblyInstruction
-  = name:Identifier __ '(' __ head:AssemblyItem? __ tail:( ',' __ AssemblyItem )* __ ')' {
+  = name:(Identifier / ReturnOpCode) __ '(' __ head:AssemblyItem? __ tail:( ',' __ AssemblyItem )* __ ')' {
     return {
       type: "FunctionalAssemblyInstruction",
       name: name,

test/doc_examples.sol

@@ -312,6 +312,19 @@ contract assemblyLocalBinding {
   }
 }
 
+contract assemblyReturn {
+  uint a = 10;
+
+  function get() constant returns(uint) {
+    assembly {
+        mstore(0x40, sload(0))
+        byte(0)
+        address(0)
+        return(0x40,32)
+    }
+  }
+}
+
 contract usesConst {
   uint const = 0;
 }