implement builtin function meta.module-variables

src/builtin/modules/math.rs

@@ -378,12 +378,12 @@ pub(crate) fn declare(f: &mut Module) {
     #[cfg(feature = "random")]
     f.insert_builtin("random", random);
 
-    f.insert_builtin_var(
-        "pi",
-        Value::Dimension(Some(Number::from(std::f64::consts::PI)), Unit::None, true),
-    );
     f.insert_builtin_var(
         "e",
         Value::Dimension(Some(Number::from(std::f64::consts::E)), Unit::None, true),
     );
+    f.insert_builtin_var(
+        "pi",
+        Value::Dimension(Some(Number::from(std::f64::consts::PI)), Unit::None, true),
+    );
 }

src/builtin/modules/meta.rs

@@ -45,7 +45,28 @@ fn module_functions(mut args: CallArgs, parser: &mut Parser<'_>) -> SassResult<V
 
 fn module_variables(mut args: CallArgs, parser: &mut Parser<'_>) -> SassResult<Value> {
     args.max_args(1)?;
-    todo!()
+
+    let module = match args.get_err(0, "module")? {
+        Value::String(s, ..) => s,
+        v => {
+            return Err((
+                format!("$module: {} is not a string.", v.inspect(args.span())?),
+                args.span(),
+            )
+                .into())
+        }
+    };
+
+    Ok(Value::Map(
+        parser
+            .modules
+            .get(&module)
+            .ok_or((
+                format!("There is no module with the namespace \"{}\".", module),
+                args.span(),
+            ))?
+            .variables(),
+    ))
 }
 
 pub(crate) fn declare(f: &mut Module) {

src/builtin/modules/mod.rs

@@ -68,6 +68,20 @@ impl Module {
                 .collect::<Vec<(Value, Value)>>(),
         )
     }
+
+    pub fn variables(&self) -> SassMap {
+        SassMap::new_with(
+            self.vars
+                .iter()
+                .map(|(key, value)| {
+                    (
+                        Value::String(key.to_string(), QuoteKind::Quoted),
+                        value.clone(),
+                    )
+                })
+                .collect::<Vec<(Value, Value)>>(),
+        )
+    }
 }
 
 pub(crate) fn declare_module_color() -> Module {

tests/meta-module.rs

@@ -0,0 +1,15 @@
+#![cfg(test)]
+
+#[macro_use]
+mod macros;
+
+test!(
+    module_functions_builtin,
+    "@use 'sass:meta';\na {\n  color: inspect(meta.module-functions(meta));\n}\n",
+    "a {\n  color: (\"feature-exists\": get-function(\"feature-exists\"), \"inspect\": get-function(\"inspect\"), \"type-of\": get-function(\"type-of\"), \"keywords\": get-function(\"keywords\"), \"global-variable-exists\": get-function(\"global-variable-exists\"), \"variable-exists\": get-function(\"variable-exists\"), \"function-exists\": get-function(\"function-exists\"), \"mixin-exists\": get-function(\"mixin-exists\"), \"content-exists\": get-function(\"content-exists\"), \"module-variables\": get-function(\"module-variables\"), \"module-functions\": get-function(\"module-functions\"), \"get-function\": get-function(\"get-function\"), \"call\": get-function(\"call\"));\n}\n"
+);
+test!(
+    module_variables_builtin,
+    "@use 'sass:meta';\n@use 'sass:math';\na {\n  color: inspect(meta.module-variables(math));\n}\n",
+    "a {\n  color: (\"e\": 2.7182818285, \"pi\": 3.1415926536);\n}\n"
+);