BUGFIX: Calling macros with no arguments could not be parsed.

integration_tests/macros_test.ucg

@@ -1,3 +1,7 @@
+let noargmacro = macro() => {
+    field1 = "value",
+};
+
 let simplemacro = macro(arg1, arg2, arg3) => {
     field1 = arg1,
     field2 = arg2,
@@ -11,9 +15,13 @@ let cplxmacro = macro(argint, argstr, argfloat) => {
     boolfield = argint == 1,
 };
 
+let noargresult = noargmacro();
 let simpleresult = simplemacro(1, 2, 3);
 let cplxresult = cplxmacro(1, "We", 3.0);
 
+assert |
+    noargresult.field1 == "value";
+|;
 assert |
     simpleresult.field1 == 1;
 |;

src/parse/mod.rs

@@ -661,12 +661,12 @@ make_fn!(
 fn tuple_to_call<'a>(
     input: SliceIter<'a, Token>,
     val: Value,
-    exprs: Vec<Expression>,
+    exprs: Option<Vec<Expression>>,
 ) -> ParseResult<'a, Expression> {
     if let Value::Selector(def) = val {
         Ok(Expression::Call(CallDef {
             macroref: def,
-            arglist: exprs,
+            arglist: exprs.unwrap_or_else(|| Vec::new()),
             pos: (&input).into(),
         }))
     } else {
@@ -693,7 +693,7 @@ fn call_expression(input: SliceIter<Token>) -> Result<SliceIter<Token>, Expressi
     let parsed = do_each!(input.clone(),
         macroname => trace_nom!(selector_value),
         _ => punct!("("),
-        args => separated!(punct!(","), trace_nom!(expression)),
+        args => optional!(separated!(punct!(","), trace_nom!(expression))),
         _ => punct!(")"),
         (macroname, args)
     );

src/parse/test.rs

@@ -887,6 +887,18 @@ fn test_call_parse() {
             pos: Position::new(1, 1, 0),
         })
     );
+
+    assert_parse!(
+        call_expression("foo ()"),
+        Expression::Call(CallDef {
+            macroref: make_selector!(
+                make_expr!("foo", Position::new(1, 1, 0)),
+                Position::new(1, 1, 0)
+            ),
+            arglist: Vec::new(),
+            pos: Position::new(1, 1, 0),
+        })
+    );
 }
 
 #[test]