Added 'header' option (#491)

README.md

@@ -178,6 +178,9 @@ object to `peg.generate`. The following options are supported:
                   valid only when `format` is set to `"globals"` or `"umd"`
   * `format` — format of the generated parser (`"amd"`, `"bare"`, `"commonjs"`, `"es"`, `"globals"`, or `"umd"`);
                valid only when `output` is set to `"source"` (default: `"bare"`)
+  * `header` — this option is only handled if it's an array or a string:
+    * `[ string1, string2, ... ]` will add each element (all expected to be strings) as a separate line comment
+    * `string` will simply append the string (e.g. `"/* eslint-disable */"`) after the `Generated by ...` comment
   * `optimize`— selects between optimizing the generated parser for parsing speed (`"speed"`) or code size (`"size"`) (default: `"speed"`)
   * `output` — if set to `"parser"` (default), the method will return generated parser object;
                if set to `"source"`, it will return parser source code as a string

gulpfile.js

@@ -53,7 +53,7 @@ task( "benchmark", () => node( "test/benchmark/run" ) );
 
 // Generate the grammar parser.
 task( "build:parser", () =>
-    node( "bin/peg src/parser.pegjs -o lib/parser.js" )
+    node( "bin/peg src/parser.pegjs -o lib/parser.js -c src/config.json" )
 );
 
 // Create the browser build.

lib/compiler/passes/generate-js.js

@@ -1325,13 +1325,27 @@ function generateJS( ast, options ) {
 
     function generateWrapper( toplevelCode ) {
 
-        function generateGeneratedByComment() {
+        function generateHeaderComment() {
 
-            return [
-                "// Generated by PEG.js 0.10.0.",
-                "//",
-                "// https://pegjs.org/"
-            ].join( "\n" );
+            let comment = "// Generated by PEG.js v0.10.0, https://pegjs.org/";
+            const header = options.header;
+
+            if ( typeof header === "string" ) {
+
+                comment += "\n\n" + header;
+
+            } else if ( Array.isArray( header ) ) {
+
+                comment += "\n\n";
+                header.forEach( data => {
+
+                    comment += "// " + data;
+
+                } );
+
+            }
+
+            return comment;
 
         }
 
@@ -1377,7 +1391,7 @@ function generateJS( ast, options ) {
             bare() {
 
                 return [
-                    generateGeneratedByComment(),
+                    generateHeaderComment(),
                     "(function() {",
                     "  \"use strict\";",
                     "",
@@ -1395,7 +1409,7 @@ function generateJS( ast, options ) {
                 const dependencyVars = Object.keys( options.dependencies );
 
                 parts.push( [
-                    generateGeneratedByComment(),
+                    generateHeaderComment(),
                     "",
                     "\"use strict\";",
                     ""
@@ -1433,7 +1447,7 @@ function generateJS( ast, options ) {
                 const dependencyVars = Object.keys( options.dependencies );
 
                 parts.push(
-                    generateGeneratedByComment(),
+                    generateHeaderComment(),
                     ""
                 );
 
@@ -1477,7 +1491,7 @@ function generateJS( ast, options ) {
                 const params = dependencyVars.join( ", " );
 
                 return [
-                    generateGeneratedByComment(),
+                    generateHeaderComment(),
                     "define(" + dependencies + ", function(" + params + ") {",
                     "  \"use strict\";",
                     "",
@@ -1493,7 +1507,7 @@ function generateJS( ast, options ) {
             globals() {
 
                 return [
-                    generateGeneratedByComment(),
+                    generateHeaderComment(),
                     "(function(root) {",
                     "  \"use strict\";",
                     "",
@@ -1522,7 +1536,7 @@ function generateJS( ast, options ) {
                 const params = dependencyVars.join( ", " );
 
                 parts.push( [
-                    generateGeneratedByComment(),
+                    generateHeaderComment(),
                     "(function(root, factory) {",
                     "  if (typeof define === \"function\" && define.amd) {",
                     "    define(" + dependencies + ", factory);",

lib/parser.js

@@ -1,6 +1,6 @@
-// Generated by PEG.js 0.10.0.
-//
-// https://pegjs.org/
+// Generated by PEG.js v0.10.0, https://pegjs.org/
+
+/* eslint-disable */
 
 "use strict";
 

src/config.json

@@ -0,0 +1,3 @@
+{
+    "header": "/* eslint-disable */"
+}