Handle positional arguments to mixins

src/main.rs

@@ -384,8 +384,8 @@ fn eat_include<I: Iterator<Item = Token>>(
         return Err((pos, "expected identifier"));
     };
     let rules = mixin
-        .call_with_args(&args)
-        .eval(super_selector, &mut scope.clone())?;
+        .args(&args)
+        .call(super_selector)?;
     Ok(rules)
 }
 
@@ -1121,4 +1121,19 @@ mod css_mixins {
         "@mixin a {\n  $a: blue;\nb {\n  $a: red;\n}  color: $a\n}\nd {\n  @include a;\n}\n",
         "d {\n  color: red;\n}\n"
     );
+    test!(
+        mixin_single_arg,
+        "@mixin a($b) {\n  color: $b;\n}\nd {\n  @include a(red);\n}\n",
+        "d {\n  color: red;\n}\n"
+    );
+    test!(
+        mixin_two_args,
+        "@mixin a($b, $c) {\n  color: $b;\n  color: $c\n}\nd {\n  @include a(red, blue);\n}\n",
+        "d {\n  color: red;\n  color: blue;\n}\n"
+    );
+    test!(
+        mixin_arg_trailing_comma,
+        "@mixin a($b, $c,) {\n  color: $b;\n  color: $c\n}\nd {\n  @include a(red, blue);\n}\n",
+        "d {\n  color: red;\n  color: blue;\n}\n"
+    );
 }

src/mixin.rs

@@ -25,12 +25,11 @@ impl Mixin {
         }
     }
 
-    pub fn call_with_args(&mut self, args: &CallArgs) -> &mut Mixin {
+    pub fn args(&mut self, args: &CallArgs) -> &mut Mixin {
         for (idx, arg) in args.0.iter().enumerate() {
             if arg.is_named() {
                 todo!("keyword args")
             } else {
-                // dbg!(&self.args.0[idx].name.clone());
                 self.scope
                     .vars
                     .insert(self.args.0[idx].name.clone(), arg.val.clone());
@@ -39,6 +38,10 @@ impl Mixin {
         self
     }
 
+    pub fn call(&mut self, super_selector: &Selector,) -> Result<Vec<Stmt>, (Pos, &'static str)> {
+        self.eval(super_selector, &mut self.scope.clone())
+    }
+
     pub fn eval(
         &mut self,
         super_selector: &Selector,