grunt-peg

A grunt multi task that generates parsers from PEG grammars.

grunt-peg

A grunt multi task that generates parsers from PEG grammars.

This plugin requires Grunt ~0.4.1

If you haven't used Grunt before, be sure to check out the Getting Started guide, as it explains how to create a Gruntfile as well as install and use Grunt plugins. Once you're familiar with that process, you may install this plugin with this command:

npm install grunt-peg --save-dev

One the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:

grunt.loadNpmTasks('grunt-peg');

Run this task with the grunt peg command.

Task targets, files and options may be specified according to the grunt Configuring tasks guide.

Any specified option will be passed through directly to PEG.js, thus you can specify any option that PEG.js supports. See the PEG.js documentation for a list of supported options.

An additional option is supported:

Type: String | function Default value: 'module.exports'

The variable to which the generated parser will be assigned in the output file.

If the exportVar is of type function, the function needs to return the variable as a String. The function gets passed the src variable to base the variable off.

In this example a PEG grammar as described in the file grammar/example.peg is used to generate parser grammar/example.js. The default export variable is used, i.e. module.exports.

grunt.initConfig({
  peg: {
    example: {
      src: "grammar/example.peg",
      dest: "grammar/example.js"
    }
  }
})

In this example a PEG grammar as described in the file grammar/example.peg is used to generate parser grammar/example.js, the export variable being Example.parser.

grunt.initConfig({
  peg: {
    example : {
      src: "grammar/example.peg",
      dest: "grammar/example.js",
      options: { exportVar: "Example.parser" }
    }
  }
})

In this example a PEG grammar as described in the file grammar/example.peg is used to generate parser grammar/example.js, the export variable being defined via a function and will result in example.

grunt.initConfig({
  peg: {
    example : {
      src: "grammar/example.peg",
      dest: "grammar/example.js",
      options: { exportVarfunction(src){ return path.basename(src[0], '.peg'); } }
    }
  }
})

In this example a PEG grammar as described in the file grammar/example.peg is used to generate parser grammar/example.js, the export variable being Example.parser. Both the task-specific trackLineAndColumn and target-specific cache options will be passed through to PEG.js.

grunt.initConfig({
  peg: {
    options: { trackLineAndColumn: true },
    example : {
      src: "grammar/example.peg",
      dest: "grammar/example.js",
      options: {
        exportVar: "Example.parser",
        cache: true
      }
    }
  }
})

It is also possible to wrap the generated parser in an Angular factory.

grunt.initConfig({
  peg: {
    options: { trackLineAndColumn: true },
    example : {
      src: "grammar/example.peg",
      dest: "grammar/example.js",
      options: {
        angular: {
          module: "pegjs",
          factory: "exampleParser"
        }
      }
    }
  }
})

It is also possible to wrap the generated parser in any code you want.

grunt.initConfig({
  peg: {
    options: { trackLineAndColumn: true },
    example : {
      src: "grammar/example.peg",
      dest: "grammar/example.js",
      options: {
        wrapperfunction (srcparser) {
          return 'define("example", [], function () { return ' + parser + '; });';
        }
      }
    }
  }
})

If you want to pass plugins to PEG.js make sure that the plugin is installed and referenced by the module name. For example, for the pegjs-coffee-plugin one should first install the plugin

npm install --save-dev pegjs-coffee-plugin

and then configure the tasks with the module name.

grunt.initConfig({
  peg: {
    options: { trackLineAndColumn: true },
    example : {
      src: "grammar/example.peg",
      dest: "grammar/example.js",
      options: {
        plugins: [ "pegjs-coffee-plugin" ]
      }
    }
  }
})

As described in issue #6 sometimes the wrong PEG.js version is downloaded by npm. The solution for now seems to be to call npm cache clear.

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using Grunt.

  • 2014-06-09 v1.4.0 Dynamic exportVar
  • 2014-05-15 v1.3.1 Add license headers to all source files
  • 2014-03-20 v1.3.0 Wrap in Angular Factory
  • 2014-01-05 v1.2.0 Support plugins
  • 2014-01-05 v1.1.0 Support PEG 0.8.0
  • 2013-08-21 v1.0.0 Remove support for old-style options
  • 2013-07-04 v0.3.0 Adhere to grunt's configuration convention
  • 2013-06-02 v0.2.0 Pass options to PEG.js
  • 2013-04-23 v0.1.0 Migrated to Grunt ~0.4.x