Add function declarations

grammar.js

@@ -226,9 +226,41 @@ module.exports = grammar({
 
     _declaration_chunks: ($) => repeat1($._declaration_chunk),
 
-    _declaration_chunk: ($) => choice(
+    _declaration_chunk: ($) => prec.left(
-      $.variable_declaration,
+      choice(
-      $.import_declaration,
+        repeat1(choice($.function_declaration, $.primitive_declaration)),
+        $.variable_declaration,
+        $.import_declaration,
+      ),
+    ),
+
+    function_declaration: ($) => seq(
+      "function",
+      $._function_declaration_common,
+      "=",
+      field("body", $._expr),
+    ),
+
+    primitive_declaration: ($) => seq(
+      "primitive",
+      $._function_declaration_common,
+    ),
+
+    _function_declaration_common: ($) => seq(
+      field("name", $.identifier),
+      field("parameters", $.parameters),
+    ),
+
+    parameters: ($) => seq(
+      "(",
+      field("parameters", sepBy(",", $._typed_field)),
+      ")",
+    ),
+
+    _typed_field: ($) => seq(
+      field("name", $.identifier),
+      ":",
+      field("type", $.identifier),
     ),
 
     variable_declaration: ($) => seq(

src/grammar.json

@@ -1040,15 +1040,169 @@
       }
     },
     "_declaration_chunk": {
-      "type": "CHOICE",
+      "type": "PREC_LEFT",
+      "value": 0,
+      "content": {
+        "type": "CHOICE",
+        "members": [
+          {
+            "type": "REPEAT1",
+            "content": {
+              "type": "CHOICE",
+              "members": [
+                {
+                  "type": "SYMBOL",
+                  "name": "function_declaration"
+                },
+                {
+                  "type": "SYMBOL",
+                  "name": "primitive_declaration"
+                }
+              ]
+            }
+          },
+          {
+            "type": "SYMBOL",
+            "name": "variable_declaration"
+          },
+          {
+            "type": "SYMBOL",
+            "name": "import_declaration"
+          }
+        ]
+      }
+    },
+    "function_declaration": {
+      "type": "SEQ",
       "members": [
         {
-          "type": "SYMBOL",
+          "type": "STRING",
-          "name": "variable_declaration"
+          "value": "function"
         },
         {
           "type": "SYMBOL",
-          "name": "import_declaration"
+          "name": "_function_declaration_common"
+        },
+        {
+          "type": "STRING",
+          "value": "="
+        },
+        {
+          "type": "FIELD",
+          "name": "body",
+          "content": {
+            "type": "SYMBOL",
+            "name": "_expr"
+          }
+        }
+      ]
+    },
+    "primitive_declaration": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "primitive"
+        },
+        {
+          "type": "SYMBOL",
+          "name": "_function_declaration_common"
+        }
+      ]
+    },
+    "_function_declaration_common": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "FIELD",
+          "name": "name",
+          "content": {
+            "type": "SYMBOL",
+            "name": "identifier"
+          }
+        },
+        {
+          "type": "FIELD",
+          "name": "parameters",
+          "content": {
+            "type": "SYMBOL",
+            "name": "parameters"
+          }
+        }
+      ]
+    },
+    "parameters": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "STRING",
+          "value": "("
+        },
+        {
+          "type": "FIELD",
+          "name": "parameters",
+          "content": {
+            "type": "CHOICE",
+            "members": [
+              {
+                "type": "SEQ",
+                "members": [
+                  {
+                    "type": "SYMBOL",
+                    "name": "_typed_field"
+                  },
+                  {
+                    "type": "REPEAT",
+                    "content": {
+                      "type": "SEQ",
+                      "members": [
+                        {
+                          "type": "STRING",
+                          "value": ","
+                        },
+                        {
+                          "type": "SYMBOL",
+                          "name": "_typed_field"
+                        }
+                      ]
+                    }
+                  }
+                ]
+              },
+              {
+                "type": "BLANK"
+              }
+            ]
+          }
+        },
+        {
+          "type": "STRING",
+          "value": ")"
+        }
+      ]
+    },
+    "_typed_field": {
+      "type": "SEQ",
+      "members": [
+        {
+          "type": "FIELD",
+          "name": "name",
+          "content": {
+            "type": "SYMBOL",
+            "name": "identifier"
+          }
+        },
+        {
+          "type": "STRING",
+          "value": ":"
+        },
+        {
+          "type": "FIELD",
+          "name": "type",
+          "content": {
+            "type": "SYMBOL",
+            "name": "identifier"
+          }
         }
       ]
     },

src/node-types.json

@@ -895,6 +895,110 @@
       }
     }
   },
+  {
+    "type": "function_declaration",
+    "named": true,
+    "fields": {
+      "body": {
+        "multiple": false,
+        "required": true,
+        "types": [
+          {
+            "type": "array_expression",
+            "named": true
+          },
+          {
+            "type": "array_value",
+            "named": true
+          },
+          {
+            "type": "assignment_expression",
+            "named": true
+          },
+          {
+            "type": "binary_expression",
+            "named": true
+          },
+          {
+            "type": "break_expression",
+            "named": true
+          },
+          {
+            "type": "for_expression",
+            "named": true
+          },
+          {
+            "type": "function_call",
+            "named": true
+          },
+          {
+            "type": "identifier",
+            "named": true
+          },
+          {
+            "type": "if_expression",
+            "named": true
+          },
+          {
+            "type": "integer_literal",
+            "named": true
+          },
+          {
+            "type": "let_expression",
+            "named": true
+          },
+          {
+            "type": "nil_literal",
+            "named": true
+          },
+          {
+            "type": "record_expression",
+            "named": true
+          },
+          {
+            "type": "record_value",
+            "named": true
+          },
+          {
+            "type": "sequence_expression",
+            "named": true
+          },
+          {
+            "type": "string_literal",
+            "named": true
+          },
+          {
+            "type": "unary_expression",
+            "named": true
+          },
+          {
+            "type": "while_expression",
+            "named": true
+          }
+        ]
+      },
+      "name": {
+        "multiple": false,
+        "required": true,
+        "types": [
+          {
+            "type": "identifier",
+            "named": true
+          }
+        ]
+      },
+      "parameters": {
+        "multiple": false,
+        "required": true,
+        "types": [
+          {
+            "type": "parameters",
+            "named": true
+          }
+        ]
+      }
+    }
+  },
   {
     "type": "if_expression",
     "named": true,
@@ -1241,10 +1345,18 @@
         "multiple": true,
         "required": false,
         "types": [
+          {
+            "type": "function_declaration",
+            "named": true
+          },
           {
             "type": "import_declaration",
             "named": true
           },
+          {
+            "type": "primitive_declaration",
+            "named": true
+          },
           {
             "type": "variable_declaration",
             "named": true
@@ -1253,6 +1365,76 @@
       }
     }
   },
+  {
+    "type": "parameters",
+    "named": true,
+    "fields": {
+      "name": {
+        "multiple": true,
+        "required": false,
+        "types": [
+          {
+            "type": "identifier",
+            "named": true
+          }
+        ]
+      },
+      "parameters": {
+        "multiple": true,
+        "required": false,
+        "types": [
+          {
+            "type": ",",
+            "named": false
+          },
+          {
+            "type": ":",
+            "named": false
+          },
+          {
+            "type": "identifier",
+            "named": true
+          }
+        ]
+      },
+      "type": {
+        "multiple": true,
+        "required": false,
+        "types": [
+          {
+            "type": "identifier",
+            "named": true
+          }
+        ]
+      }
+    }
+  },
+  {
+    "type": "primitive_declaration",
+    "named": true,
+    "fields": {
+      "name": {
+        "multiple": false,
+        "required": true,
+        "types": [
+          {
+            "type": "identifier",
+            "named": true
+          }
+        ]
+      },
+      "parameters": {
+        "multiple": false,
+        "required": true,
+        "types": [
+          {
+            "type": "parameters",
+            "named": true
+          }
+        ]
+      }
+    }
+  },
   {
     "type": "record_expression",
     "named": true,
@@ -1510,6 +1692,10 @@
           "type": "function_call",
           "named": true
         },
+        {
+          "type": "function_declaration",
+          "named": true
+        },
         {
           "type": "identifier",
           "named": true
@@ -1534,6 +1720,10 @@
           "type": "nil_literal",
           "named": true
         },
+        {
+          "type": "primitive_declaration",
+          "named": true
+        },
         {
           "type": "record_expression",
           "named": true
@@ -2008,6 +2198,10 @@
     "type": "for",
     "named": false
   },
+  {
+    "type": "function",
+    "named": false
+  },
   {
     "type": "identifier",
     "named": true
@@ -2044,6 +2238,10 @@
     "type": "operator",
     "named": true
   },
+  {
+    "type": "primitive",
+    "named": false
+  },
   {
     "type": "then",
     "named": false

test/corpus/declarations.txt

@@ -6,6 +6,67 @@ Empty declarations
 
 (source_file)
 
+================================================================================
+Function declaration
+================================================================================
+
+function func(a: int, b: int) = "string"
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (function_declaration
+    name: (identifier)
+    parameters: (parameters
+      name: (identifier)
+      type: (identifier)
+      name: (identifier)
+      type: (identifier))
+    body: (string_literal)))
+
+================================================================================
+Function declaration single parameter
+================================================================================
+
+function func(a: int) = "string"
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (function_declaration
+    name: (identifier)
+    parameters: (parameters
+      name: (identifier)
+      type: (identifier))
+    body: (string_literal)))
+
+================================================================================
+Function declaration no parameters
+================================================================================
+
+function func() = "string"
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (function_declaration
+    name: (identifier)
+    parameters: (parameters)
+    body: (string_literal)))
+
+================================================================================
+Primitive declaration
+================================================================================
+
+primitive prim()
+
+--------------------------------------------------------------------------------
+
+(source_file
+  (primitive_declaration
+    name: (identifier)
+    parameters: (parameters)))
+
 ================================================================================
 Variable declaration
 ================================================================================