Adds a location object to snapdragon token or AST node.
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Install with npm:
$ npm install --save snapdragon-locationAdds a .loc object to tokens that looks something like this:
{
source: 'string',
start: { index: 0, column: 1, line: 1 },
end: { index: 3, column: 4, line: 1 },
range: [0, 3] // getter
}When used as snapdragon-lexer plugin, this adds a .location() method to the instance and patches the lexer.lex() and lexer.handle() methods to automatically add location objects to tokens.
There is a more detailed example below.
Heads up!
If you prefer .position over .loc, use snapdragon-position instead.
The main export is a function that can be used as a plugin with snapdragon-lexer, or called directly with an instance of snapdragon-lexer.
Sets the start location and returns a function for setting the end location.
Params
name{String|Object}: (optional) Snapdragon Lexer or Tokenizer instance, or the name to use for the location property on the token. Default istoc.target{Object}: Snapdragon Lexer or Tokenizer instancereturns{Function}: Returns a function that takes atokenas its only argument
Example
const location = require('snapdragon-location');
const Lexer = require('snapdragon-lexer');
const lexer = new Lexer('foo/bar');
lexer.capture('slash', /^\//);
lexer.capture('text', /^\w+/);
const loc = location(lexer);
const token = loc(lexer.advance());
console.log(token);Use as a plugin to add a .location method to your snapdragon-lexer or [snapdragon-tokenizer][] instance to automatically add a location object to tokens when the .lex() or .handle() methods are used.
Example
const Lexer = require('snapdragon-lexer');
const location = require('snapdragon-location');
const lexer = new Lexer();
lexer.use(location());Get the current source position, with index, column and line. Used by .location() to create the "start" and "end" positions.
returns{Object}: Returns an object with the current source position.
Example
const Lexer = require('snapdragon-lexer');
const lexer = new Lexer();
console.log(lexer.position());
//=> Position { index: 0, column: 0, line: 1 };Returns a function for getting the current location.
returns{Function}: Returns a function that takes atokenas its only argument, and patches a.locproperty onto the token.
Example
const Lexer = require('snapdragon-lexer');
const lexer = new Lexer('foo/bar');
lexer.use(location());
lexer.set('text', function(tok) {
// get start location before advancing lexer
const loc = this.location();
const match = this.match(/^\w+/);
if (match) {
// get end location after advancing lexer (with .match)
return loc(this.token(match));
}
});Params
start{Object}: (required) Starting positionend{Object}: (required) Ending positiontarget{Object}: (optional) Snapdragon Lexer or Tokenizer instancereturns{Object}
Example
const Lexer = require('snapdragon-lexer');
const Position = require('snapdragon-location').Position;
const lexer = new Lexer('foo/bar');
lexer.capture('text', /^\w+/);
lexer.advance();
console.log(new Position(lexer));
//=> Position { index: 3, column: 4, line: 1 }Params
start{Object}: (required) Starting positionend{Object}: (required) Ending positiontarget{Object}: (optional) Snapdragon Lexer or Tokenizer instancereturns{Object}
Example
const Lexer = require('snapdragon-lexer');
const location = require('snapdragon-position');
const lexer = new Lexer('foo/bar')
.capture('slash', /^\//)
.capture('text', /^\w+/);
const start = new location.Position(lexer);
lexer.advance();
const end = new location.Position(lexer);
console.log(new location.Location(start, end, lexer));
// Location {
// source: undefined,
// start: Position { index: 0, column: 1, line: 1 },
// end: Position { index: 3, column: 4, line: 1 } }When used as a plugin, this adds a .position() method to a snapdragon-lexer instance, for adding position information to tokens.
Example
const location = require('snapdragon-location');
const Lexer = require('snapdragon-lexer');
const lexer = new Lexer('foo/bar');
lexer.use(location());
lexer.capture('slash', /^\//);
lexer.capture('text', /^\w+/);
var token = lexer.advance();
console.log(token);Adds a .loc object to the token, like this:
Token {
type: 'text',
value: 'foo',
match: [ 'foo', index: 0, input: 'foo/*' ],
loc: {
start: { index: 0, column: 1, line: 1 },
end: { index: 3, column: 4, line: 1 },
range: [0, 3] // getter
}
}See the Token documentation for more details about the Token object.
interface Token {
type: string;
value: string;
match: array | undefined;
loc: Location;
}The token.loc property contains source string location information on the token.
interface Location {
source: string | undefined;
start: Position;
end: Position;
range: array (getter)
}source{string|undefined} - the source location provided bylexer.options.source. Typically this is a filename, but could also bestringor any user defined value.start{object} - start position object, which is the position of the first character of the lexed source string.end{object} - end position object, which is the position of the last character of the lexed source string.range{array} - getter that returns an array with the following values:[loc.start.index, loc.end.index]
Each Position object consists of an index number (0-based), a column number (0-based), and a line number (1-based):
interface Position {
index: number; // >= 0
column: number; // >= 0,
line: number; // >= 1
}line{string|undefined} - the source location provided bylexer.options.source. Typically this is a filename, but could also bestringor any user defined value.column{object} - start position object, which is the position of the first character of the lexed source string.end{object} - end position object, which is the position of the last character of the lexed source string.
const Lexer = require('snapdragon-lexer');
const lexer = new Lexer('foo/*', { source: 'string' });
lexer.use(location());
lexer.capture('star', /^\*/);
lexer.capture('slash', /^\//);
lexer.capture('text', /^\w+/);
lexer.tokenize();
console.log(lexer.tokens);Results in:
[
{
type: 'text',
val: 'foo',
match: ['foo', index: 0, input: 'foo/*'],
loc: {
source: 'string',
start: { index: 0, column: 1, line: 1 },
end: { index: 3, column: 4, line: 1 },
range: [0, 3]
}
},
{
type: 'slash',
val: '/',
match: ['/', index: 0, input: '/*'],
loc: {
source: 'string',
start: { index: 3, column: 4, line: 1 },
end: { index: 4, column: 5, line: 1 },
range: [3, 4]
}
},
{
type: 'star',
val: '*',
match: ['*', index: 0, input: '*'],
loc: {
source: 'string',
start: { index: 4, column: 5, line: 1 },
end: { index: 5, column: 6, line: 1 },
range: [4, 5]
}
}
]Contributing
Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.
Please read the contributing guide for advice on opening issues, pull requests, and coding standards.
Running Tests
Running and reviewing unit tests is a great way to get familiarized with a library and its API. You can install dependencies and run tests with the following command:
$ npm install && npm testBuilding docs
(This project's readme.md is generated by verb, please don't edit the readme directly. Any changes to the readme must be made in the .verb.md readme template.)
To generate the readme, run the following command:
$ npm install -g verbose/verb#dev verb-generate-readme && verbYou might also be interested in these projects:
- snapdragon-capture: Snapdragon plugin that adds a capture method to the parser instance. | homepage
- snapdragon-node: Snapdragon utility for creating a new AST node in custom code, such as plugins. | homepage
- snapdragon-util: Utilities for the snapdragon parser/compiler. | homepage
Jon Schlinkert
Copyright © 2018, Jon Schlinkert. Released under the MIT License.
This file was generated by verb-generate-readme, v0.6.0, on January 08, 2018.