add support for @apply statements

fixes #5.

corpus/statements.txt

@@ -254,6 +254,17 @@ Extend statements
         (block (extend_statement (plain_value)) 
           (extend_statement (class_selector (class_name)))))))) 
 
+==============================
+Apply statements
+==============================
+
+@apply fill-red-50 border-black col-span-1;
+
+---
+
+(stylesheet
+  (apply_statement (plain_value) (plain_value) (plain_value)))
+
 =================================
 Operators
 =================================

grammar.js

@@ -24,6 +24,7 @@ module.exports = grammar({
         $.supports_statement,
         $.use_statement,
         $.forward_statement,
+        $.apply_statement,
         $.mixin_statement,
         $.include_statement,
         $.if_statement,
@@ -76,6 +77,8 @@ module.exports = grammar({
 
     forward_statement: ($) => seq("@forward", $._value, ";"),
 
+    apply_statement: ($) => seq("@apply", repeat($._value), ";"),
+
     parameters: ($) => seq("(", sep1(",", $.parameter), ")"),
 
     parameter: ($) =>

src/grammar.json

@@ -51,6 +51,10 @@
           "type": "SYMBOL",
           "name": "forward_statement"
         },
+        {
+          "type": "SYMBOL",
+          "name": "apply_statement"
+        },
         {
           "type": "SYMBOL",
           "name": "mixin_statement"
@@ -445,6 +449,26 @@
         }
       ]
     },
+    "apply_statement": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "@apply"
+        },
+        {
+          "type": "REPEAT",
+          "content": {
+            "type": "SYMBOL",
+            "name": "_value"
+          }
+        },
+        {
+          "type": "STRING",
+          "value": ";"
+        }
+      ]
+    },
     "parameters": {
       "type": "SEQ",
       "members": [

src/node-types.json

@@ -62,6 +62,53 @@
       ]
     }
   },
+  {
+    "type": "apply_statement",
+    "named": true,
+    "fields": {},
+    "children": {
+      "multiple": true,
+      "required": false,
+      "types": [
+        {
+          "type": "binary_expression",
+          "named": true
+        },
+        {
+          "type": "call_expression",
+          "named": true
+        },
+        {
+          "type": "color_value",
+          "named": true
+        },
+        {
+          "type": "float_value",
+          "named": true
+        },
+        {
+          "type": "integer_value",
+          "named": true
+        },
+        {
+          "type": "parenthesized_value",
+          "named": true
+        },
+        {
+          "type": "plain_value",
+          "named": true
+        },
+        {
+          "type": "string_value",
+          "named": true
+        },
+        {
+          "type": "variable_value",
+          "named": true
+        }
+      ]
+    }
+  },
   {
     "type": "argument",
     "named": true,
@@ -2366,6 +2413,10 @@
       "multiple": true,
       "required": false,
       "types": [
+        {
+          "type": "apply_statement",
+          "named": true
+        },
         {
           "type": "at_rule",
           "named": true
@@ -2816,6 +2867,10 @@
     "type": ">=",
     "named": false
   },
+  {
+    "type": "@apply",
+    "named": false
+  },
   {
     "type": "@at-root",
     "named": false