Add assignment

grammar.js

@@ -1,9 +1,41 @@
 module.exports = grammar({
   name: "blueprint",
 
+  extras: ($) => [
+    /\s+/,
+  ],
+
   rules: {
-    // TODO: add the actual grammar rules
+    source_file: ($) => repeat($._definition),
-    source_file: $ => 'hello',
+
+    _definition: ($) => choice(
+      $.assignment,
+    ),
+
+    // Definitions {{{
+
+    assignment: ($) => seq(
+      field("left", $.identifier),
+      field("operator", "="),
+      field("right", $._expr),
+    ),
+
+    // }}}
+
+    // Expressions {{{
+
+    _expr: ($) => choice(
+      // Literals
+      $.identifier,
+      $.integer_literal,
+    ),
+
+    // The Blueprint scanner makes use of Go's lexer, so copy their rule
+    identifier: (_) => /[_\p{XID_Start}][_\p{XID_Continue}]*/,
+
+    integer_literal: (_) => /[0-9]+/,
+
+    // }}}
   }
 });
 

src/grammar.json

@@ -2,14 +2,76 @@
   "name": "blueprint",
   "rules": {
     "source_file": {
-      "type": "STRING",
+      "type": "REPEAT",
-      "value": "hello"
+      "content": {
+        "type": "SYMBOL",
+        "name": "_definition"
+      }
+    },
+    "_definition": {
+      "type": "CHOICE",
+      "members": [
+        {
+          "type": "SYMBOL",
+          "name": "assignment"
+        }
+      ]
+    },
+    "assignment": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "FIELD",
+          "name": "left",
+          "content": {
+            "type": "SYMBOL",
+            "name": "identifier"
+          }
+        },
+        {
+          "type": "FIELD",
+          "name": "operator",
+          "content": {
+            "type": "STRING",
+            "value": "="
+          }
+        },
+        {
+          "type": "FIELD",
+          "name": "right",
+          "content": {
+            "type": "SYMBOL",
+            "name": "_expr"
+          }
+        }
+      ]
+    },
+    "_expr": {
+      "type": "CHOICE",
+      "members": [
+        {
+          "type": "SYMBOL",
+          "name": "identifier"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "integer_literal"
+        }
+      ]
+    },
+    "identifier": {
+      "type": "PATTERN",
+      "value": "[_\\p{XID_Start}][_\\p{XID_Continue}]*"
+    },
+    "integer_literal": {
+      "type": "PATTERN",
+      "value": "[0-9]+"
     }
   },
   "extras": [
     {
       "type": "PATTERN",
-      "value": "\\s"
+      "value": "\\s+"
     }
   ],
   "conflicts": [],

src/node-types.json

@@ -1,11 +1,69 @@
 [
+  {
+    "type": "assignment",
+    "named": true,
+    "fields": {
+      "left": {
+        "multiple": false,
+        "required": true,
+        "types": [
+          {
+            "type": "identifier",
+            "named": true
+          }
+        ]
+      },
+      "operator": {
+        "multiple": false,
+        "required": true,
+        "types": [
+          {
+            "type": "=",
+            "named": false
+          }
+        ]
+      },
+      "right": {
+        "multiple": false,
+        "required": true,
+        "types": [
+          {
+            "type": "identifier",
+            "named": true
+          },
+          {
+            "type": "integer_literal",
+            "named": true
+          }
+        ]
+      }
+    }
+  },
   {
     "type": "source_file",
     "named": true,
-    "fields": {}
+    "fields": {},
+    "children": {
+      "multiple": true,
+      "required": false,
+      "types": [
+        {
+          "type": "assignment",
+          "named": true
+        }
+      ]
+    }
   },
   {
-    "type": "hello",
+    "type": "=",
     "named": false
+  },
+  {
+    "type": "identifier",
+    "named": true
+  },
+  {
+    "type": "integer_literal",
+    "named": true
   }
 ]

test/corpus/definitions.txt

@@ -0,0 +1,50 @@
+================================================================================
+Empty file
+================================================================================
+
+--------------------------------------------------------------------------------
+
+(source_file)
+
+================================================================================
+Integer assignment
+================================================================================
+
+foo = 42
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (assignment
+    (identifier)
+    (integer_literal)))
+
+================================================================================
+Variable assignment
+================================================================================
+
+foo = bar
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (assignment
+    (identifier)
+    (identifier)))
+
+================================================================================
+Multiple assignments
+================================================================================
+
+foo = 12
+bar = 27
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (assignment
+    (identifier)
+    (integer_literal))
+  (assignment
+    (identifier)
+    (integer_literal)))