Fast, pluggable and easy-to-use parser-renderer factory.
Install with npm:
$ npm install --save snapdragon
Created by jonschlinkert and doowb.
Features
Breaking changes
Substantial breaking changes were made in v0.5.0! Most of these changes are part of a larger refactor that will be finished in 0.6.0, including the introduction of a Lexer
class.
Compiler
.render
method was renamed to .compile
var Snapdragon = require('snapdragon');
var snapdragon = new Snapdragon();
Parse
var ast = snapdragon.parser('some string', options)
// parser middleware that can be called by other middleware
.set('foo', function () {})
// parser middleware, runs immediately in the order defined
.use(bar())
.use(baz())
Render
// pass the `ast` from the parse method
var res = snapdragon.compiler(ast)
// compiler middleware, called when the name of the middleware
// matches the `node.type` (defined in a parser middleware)
.set('bar', function () {})
.set('baz', function () {})
.compile()
See the examples.
Parsers
Parsers are middleware functions used for parsing a string into an ast node.
var ast = snapdragon.parser(str, options)
.use(function() {
var pos = this.position();
var m = this.match(/^\./);
if (!m) return;
return pos({
// `type` specifies the compiler to use
type: 'dot',
val: m[0]
});
})
AST node
When the parser finds a match, pos()
is called, pushing a token for that node onto the ast that looks something like:
{ type: 'dot',
val: '.',
position:
{ start: { lineno: 1, column: 1 },
end: { lineno: 1, column: 2 } }}
Renderers
Renderers are named middleware functions that visit over an array of ast nodes to compile a string.
var res = snapdragon.compiler(ast)
.set('dot', function (node) {
console.log(node.val)
//=> '.'
return this.emit(node.val);
})
Source maps
If you want source map support, make sure to emit the position as well.
var res = snapdragon.compiler(ast)
.set('dot', function (node) {
return this.emit(node.val, node.position);
})
A parser middleware is a function that returns an abject called a token
. This token is pushed onto the AST as a node.
Example token
{ type: 'dot',
val: '.',
position:
{ start: { lineno: 1, column: 1 },
end: { lineno: 1, column: 2 } }}
Example parser middleware
Match a single .
in a string:
this.position()
.match
methodundefined
pos()
is called, which returns a token with:
type
: the name of the [compiler] to useval
: The actual value captured by the regex. In this case, a .
. Note that you can capture and return whatever will be needed by the corresponding [compiler].Renderers are run when the name of the compiler middleware matches the type
defined on an ast node
(which is defined in a parser).
Example
Exercise: Parse a dot, then compile it as an escaped dot.
var ast = snapdragon.parser('.')
.use(function () {
var pos = this.position();
var m = this.match(/^\./);
if (!m) return;
return pos({
// define the `type` of compiler to use
type: 'dot',
val: m[0]
})
})
var result = snapdragon.compiler(ast)
.set('dot', function (node) {
return this.emit('\\' + node.val);
})
.compile()
console.log(result.output);
//=> '\.'
Create a new Parser
with the given input
and options
.
Params
input
{String}options
{Object}Define a non-enumberable property on the Parser
instance.
Example
parser.define('foo', 'bar');
Params
key
{String}: propery nameval
{any}: property valuereturns
{Object}: Returns the Parser instance for chaining.Set parser name
with the given fn
Params
name
{String}fn
{Function}Get parser name
Params
name
{String}Push a token
onto the type
stack.
Params
type
{String}returns
{Object} token
Pop a token off of the type
stack
Params
type
{String}returns
{Object}: Returns a tokenReturn true if inside a stack
node. Types are braces
, parens
or brackets
.
Params
type
{String}returns
{Boolean}Example
parser.isType(node, 'brace');
Params
node
{Object}type
{String}returns
{Boolean}Define a non-enumberable property on the Compiler
instance.
Example
compiler.define('foo', 'bar');
Params
key
{String}: propery nameval
{any}: property valuereturns
{Object}: Returns the Compiler instance for chaining.Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.
Commits | Contributor<br/> |
---|---|
106 | jonschlinkert |
2 | doowb |
(This document was generated by verb-generate-readme (a verb generator), please don't edit the readme directly. Any changes to the readme must be made in .verb.md.)
To generate the readme and API documentation with verb:
$ npm install -g verb verb-generate-readme && verb
Install dev dependencies:
$ npm install -d && npm test
Jon Schlinkert
Copyright © 2016, Jon Schlinkert. Released under the MIT license.
This file was generated by verb-generate-readme, v0.1.31, on October 10, 2016.
# snapdragon [![NPM version](https://img.shields.io/npm/v/snapdragon.svg?style=flat)](https://www.npmjs.com/package/snapdragon) [![NPM downloads](https://img.shields.io/npm/dm/snapdragon.svg?style=flat)](https://npmjs.org/package/snapdragon) [![Build Status](https://img.shields.io/travis/jonschlinkert/snapdragon.svg?style=flat)](https://travis-ci.org/jonschlinkert/snapdragon) > Fast, pluggable and easy-to-use parser-renderer factory. ## Install Install with [npm](https://www.npmjs.com/): ```sh $ npm install --save snapdragon ``` Created by [jonschlinkert](https://github.com/jonschlinkert) and [doowb](https://github.com/doowb). **Features** * Bootstrap your own parser, get sourcemap support for free * All parsing and compiling is handled by simple, reusable middleware functions * Inspired by the parsers in [pug](http://jade-lang.com) and [css](https://github.com/reworkcss/css). ## History ### v0.5.0 **Breaking changes** Substantial breaking changes were made in v0.5.0! Most of these changes are part of a larger refactor that will be finished in 0.6.0, including the introduction of a `Lexer` class. * Renderer was renamed to `Compiler` * the `.render` method was renamed to `.compile` * Many other smaller changes. A more detailed overview will be provided in 0.6.0. If you don't have to time review code, I recommend you wait for the 0.6.0 release. ## Usage examples ```js var Snapdragon = require('snapdragon'); var snapdragon = new Snapdragon(); ``` **Parse** ```js var ast = snapdragon.parser('some string', options) // parser middleware that can be called by other middleware .set('foo', function () {}) // parser middleware, runs immediately in the order defined .use(bar()) .use(baz()) ``` **Render** ```js // pass the `ast` from the parse method var res = snapdragon.compiler(ast) // compiler middleware, called when the name of the middleware // matches the `node.type` (defined in a parser middleware) .set('bar', function () {}) .set('baz', function () {}) .compile() ``` See the [examples](./examples/). ## Getting started **Parsers** Parsers are middleware functions used for parsing a string into an ast node. ```js var ast = snapdragon.parser(str, options) .use(function() { var pos = this.position(); var m = this.match(/^\./); if (!m) return; return pos({ // `type` specifies the compiler to use type: 'dot', val: m[0] }); }) ``` **AST node** When the parser finds a match, `pos()` is called, pushing a token for that node onto the ast that looks something like: ```js { type: 'dot', val: '.', position: { start: { lineno: 1, column: 1 }, end: { lineno: 1, column: 2 } }} ``` **Renderers** Renderers are _named_ middleware functions that visit over an array of ast nodes to compile a string. ```js var res = snapdragon.compiler(ast) .set('dot', function (node) { console.log(node.val) //=> '.' return this.emit(node.val); }) ``` **Source maps** If you want source map support, make sure to emit the position as well. ```js var res = snapdragon.compiler(ast) .set('dot', function (node) { return this.emit(node.val, node.position); }) ``` ## Docs ### Parser middleware A parser middleware is a function that returns an abject called a `token`. This token is pushed onto the AST as a node. **Example token** ```js { type: 'dot', val: '.', position: { start: { lineno: 1, column: 1 }, end: { lineno: 1, column: 2 } }} ``` **Example parser middleware** Match a single `.` in a string: 1. Get the starting position by calling `this.position()` 2. pass a regex for matching a single dot to the `.match` method 3. if **no match** is found, return `undefined` 4. if a **match** is found, `pos()` is called, which returns a token with: - `type`: the name of the [compiler] to use - `val`: The actual value captured by the regex. In this case, a `.`. Note that you can capture and return whatever will be needed by the corresponding [compiler]. - The ending position: automatically calculated by adding the length of the first capture group to the starting position. ## Renderer middleware Renderers are run when the name of the compiler middleware matches the `type` defined on an ast `node` (which is defined in a parser). **Example** Exercise: Parse a dot, then compile it as an escaped dot. ```js var ast = snapdragon.parser('.') .use(function () { var pos = this.position(); var m = this.match(/^\./); if (!m) return; return pos({ // define the `type` of compiler to use type: 'dot', val: m[0] }) }) var result = snapdragon.compiler(ast) .set('dot', function (node) { return this.emit('\\' + node.val); }) .compile() console.log(result.output); //=> '\.' ``` ## API ### [Parser](lib/parser.js#L19) Create a new `Parser` with the given `input` and `options`. **Params** * `input` **{String}** * `options` **{Object}** ### [.define](lib/parser.js#L103) Define a non-enumberable property on the `Parser` instance. **Example** ```js parser.define('foo', 'bar'); ``` **Params** * `key` **{String}**: propery name * `val` **{any}**: property value * `returns` **{Object}**: Returns the Parser instance for chaining. Set parser `name` with the given `fn` **Params** * `name` **{String}** * `fn` **{Function}** Get parser `name` **Params** * `name` **{String}** Push a `token` onto the `type` stack. **Params** * `type` **{String}** * `returns` **{Object}** `token` Pop a token off of the `type` stack **Params** * `type` **{String}** * `returns` **{Object}**: Returns a token Return true if inside a `stack` node. Types are `braces`, `parens` or `brackets`. **Params** * `type` **{String}** * `returns` **{Boolean}** **Example** ```js parser.isType(node, 'brace'); ``` **Params** * `node` **{Object}** * `type` **{String}** * `returns` **{Boolean}** ### [.define](lib/compiler.js#L71) Define a non-enumberable property on the `Compiler` instance. **Example** ```js compiler.define('foo', 'bar'); ``` **Params** * `key` **{String}**: propery name * `val` **{any}**: property value * `returns` **{Object}**: Returns the Compiler instance for chaining. ## About ### Related projects * [braces](https://www.npmjs.com/package/braces): Fastest brace expansion for node.js, with the most complete support for the Bash 4.3 braces… [more](https://github.com/jonschlinkert/braces) | [homepage](https://github.com/jonschlinkert/braces "Fastest brace expansion for node.js, with the most complete support for the Bash 4.3 braces specification.") * [expand-brackets](https://www.npmjs.com/package/expand-brackets): Expand POSIX bracket expressions (character classes) in glob patterns. | [homepage](https://github.com/jonschlinkert/expand-brackets "Expand POSIX bracket expressions (character classes) in glob patterns.") * [extglob](https://www.npmjs.com/package/extglob): Convert extended globs to regex-compatible strings. Add (almost) the expressive power of regular expressions to… [more](https://github.com/jonschlinkert/extglob) | [homepage](https://github.com/jonschlinkert/extglob "Convert extended globs to regex-compatible strings. Add (almost) the expressive power of regular expressions to glob patterns.") * [micromatch](https://www.npmjs.com/package/micromatch): Glob matching for javascript/node.js. A drop-in replacement and faster alternative to minimatch and multimatch. | [homepage](https://github.com/jonschlinkert/micromatch "Glob matching for javascript/node.js. A drop-in replacement and faster alternative to minimatch and multimatch.") ### Contributing Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new). ### Contributors | **Commits** | **Contributor**<br/> | | --- | --- | | 106 | [jonschlinkert](https://github.com/jonschlinkert) | | 2 | [doowb](https://github.com/doowb) | ### Building docs _(This document was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme) (a [verb](https://github.com/verbose/verb) generator), please don't edit the readme directly. Any changes to the readme must be made in [.verb.md](.verb.md).)_ To generate the readme and API documentation with [verb](https://github.com/verbose/verb): ```sh $ npm install -g verb verb-generate-readme && verb ``` ### Running tests Install dev dependencies: ```sh $ npm install -d && npm test ``` ### Author **Jon Schlinkert** * [github/jonschlinkert](https://github.com/jonschlinkert) * [twitter/jonschlinkert](http://twitter.com/jonschlinkert) ### License Copyright © 2016, [Jon Schlinkert](https://github.com/jonschlinkert). Released under the [MIT license](https://github.com/jonschlinkert/snapdragon/blob/master/LICENSE). *** _This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.1.31, on October 10, 2016._