https://github.com/anko/sexpr-plus

JS S-expression parser with quoting and comments
https://github.com/anko/sexpr-plus

Last synced: about 1 year ago
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JS S-expression parser with quoting and comments

• Host: GitHub
• URL: https://github.com/anko/sexpr-plus
• Owner: anko
• License: mit
• Created: 2015-02-22T15:41:43.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2016-01-19T00:29:30.000Z (over 10 years ago)
• Last Synced: 2025-03-08T22:16:19.704Z (over 1 year ago)
• Language: LiveScript
• Homepage:
• Size: 0 Bytes
• Stars: 8
• Watchers: 4
• Forks: 3
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# sexpr-plus [![npm package](https://img.shields.io/npm/v/sexpr-plus.svg?style=flat-square)][1] [![CI status](https://img.shields.io/travis/anko/sexpr-plus.svg?style=flat-square)][2]

Recursive descent parser for S-expressions, with features useful for writing an

S-expr-based programming language.  Written for [eslisp][3], but generalisable.

Outputs an array containing objects representing parsed forms:

-   Lists are parsed to `{ type: "list", content: [ ... ] }`.

-   Atoms are parsed to `{ type: "atom", content: "" }`.

-   Strings (delimited with `"`s) are parsed to `{ type: "string", content:

    "" }`.  They support the same escape sequences as JavaScript

    strings: `\"`, `\\`, `\n`, `\r`, `\t`, `\f`, and `\b`.

-   Supports quote, quasiquote, unquote and unquote-splicing, with `'`, `` `

    ``, `,` and `,@`.  They're turned into the appropriate atoms.

-   Comments are from `;` til end of line.  They are not present in the output.

Empty inputs or inputs containing only comments produce an empty array.

Forked from the more minimal [fwg/s-expression][4].

## Node locations

All output nodes also have a `location` property, showing where in the input

that node originated:

    {

        start : { offset, line, column },

        end : { offset, line, column }

    }

All are integers: `offset` is the number of characters since the input, `line`

and `column` are 1-based and self-explanatory.

These may be handy for constructing source maps or showing more detailed error

messages.

## Usage

    npm i sexpr-plus

```js

var parse = require("sexpr-plus").parse;

```

Call `parse` with a string containing code to parse.

If you need to catch and distinguish between different types of `Error` with

`instanceof` while parsing, the syntax error prototype is available at

`require("sexpr-plus").SyntaxError`.

## License

[MIT][5].

[1]: https://www.npmjs.com/package/sexpr-plus

[2]: https://travis-ci.org/anko/sexpr-plus

[3]: https://github.com/anko/eslisp

[4]: https://github.com/fwg/s-expression

[5]: LICENSE