diff options
Diffstat (limited to 'desktop/node_modules/spdx-expression-parse/README.md')
-rw-r--r-- | desktop/node_modules/spdx-expression-parse/README.md | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/desktop/node_modules/spdx-expression-parse/README.md b/desktop/node_modules/spdx-expression-parse/README.md new file mode 100644 index 0000000..9406462 --- /dev/null +++ b/desktop/node_modules/spdx-expression-parse/README.md @@ -0,0 +1,91 @@ +This package parses [SPDX license expression](https://spdx.org/spdx-specification-21-web-version#h.jxpfx0ykyb60) strings describing license terms, like [package.json license strings](https://docs.npmjs.com/files/package.json#license), into consistently structured ECMAScript objects. The npm command-line interface depends on this package, as do many automatic license-audit tools. + +In a nutshell: + +```javascript +var parse = require('spdx-expression-parse') +var assert = require('assert') + +assert.deepEqual( + // Licensed under the terms of the Two-Clause BSD License. + parse('BSD-2-Clause'), + {license: 'BSD-2-Clause'} +) + +assert.throws(function () { + // An invalid SPDX license expression. + // Should be `Apache-2.0`. + parse('Apache 2') +}) + +assert.deepEqual( + // Dual licensed under either: + // - LGPL 2.1 + // - a combination of Three-Clause BSD and MIT + parse('(LGPL-2.1 OR BSD-3-Clause AND MIT)'), + { + left: {license: 'LGPL-2.1'}, + conjunction: 'or', + right: { + left: {license: 'BSD-3-Clause'}, + conjunction: 'and', + right: {license: 'MIT'} + } + } +) +``` + +The syntax comes from the [Software Package Data eXchange (SPDX)](https://spdx.org/), a standard from the [Linux Foundation](https://www.linuxfoundation.org) for shareable data about software package license terms. SPDX aims to make sharing and auditing license data easy, especially for users of open-source software. + +The bulk of the SPDX standard describes syntax and semantics of XML metadata files. This package implements two lightweight, plain-text components of that larger standard: + +1. The [license list](https://spdx.org/licenses), a mapping from specific string identifiers, like `Apache-2.0`, to standard form license texts and bolt-on license exceptions. The [spdx-license-ids](https://www.npmjs.com/package/spdx-license-ids) and [spdx-exceptions](https://www.npmjs.com/package/spdx-exceptions) packages implement the license list. `spdx-expression-parse` depends on and `require()`s them. + + Any license identifier from the license list is a valid license expression: + + ```javascript + var identifiers = [] + .concat(require('spdx-license-ids')) + .concat(require('spdx-license-ids/deprecated')) + + identifiers.forEach(function (id) { + assert.deepEqual(parse(id), {license: id}) + }) + ``` + + So is any license identifier `WITH` a standardized license exception: + + ```javascript + identifiers.forEach(function (id) { + require('spdx-exceptions').forEach(function (e) { + assert.deepEqual( + parse(id + ' WITH ' + e), + {license: id, exception: e} + ) + }) + }) + ``` + +2. The license expression language, for describing simple and complex license terms, like `MIT` for MIT-licensed and `(GPL-2.0 OR Apache-2.0)` for dual-licensing under GPL 2.0 and Apache 2.0. `spdx-expression-parse` itself implements license expression language, exporting a parser. + + ```javascript + assert.deepEqual( + // Licensed under a combination of: + // - the MIT License AND + // - a combination of: + // - LGPL 2.1 (or a later version) AND + // - Three-Clause BSD + parse('(MIT AND (LGPL-2.1+ AND BSD-3-Clause))'), + { + left: {license: 'MIT'}, + conjunction: 'and', + right: { + left: {license: 'LGPL-2.1', plus: true}, + conjunction: 'and', + right: {license: 'BSD-3-Clause'} + } + } + ) + ``` + +The Linux Foundation and its contributors license the SPDX standard under the terms of [the Creative Commons Attribution License 3.0 Unported (SPDX: "CC-BY-3.0")](http://spdx.org/licenses/CC-BY-3.0). "SPDX" is a United States federally registered trademark of the Linux Foundation. The authors of this package license their work under the terms of the MIT License. |