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'use strict'
var licenses = []
.concat(require('spdx-license-ids'))
.concat(require('spdx-license-ids/deprecated'))
var exceptions = require('spdx-exceptions')
module.exports = function (source) {
var index = 0
function hasMore () {
return index < source.length
}
// `value` can be a regexp or a string.
// If it is recognized, the matching source string is returned and
// the index is incremented. Otherwise `undefined` is returned.
function read (value) {
if (value instanceof RegExp) {
var chars = source.slice(index)
var match = chars.match(value)
if (match) {
index += match[0].length
return match[0]
}
} else {
if (source.indexOf(value, index) === index) {
index += value.length
return value
}
}
}
function skipWhitespace () {
read(/[ ]*/)
}
function operator () {
var string
var possibilities = ['WITH', 'AND', 'OR', '(', ')', ':', '+']
for (var i = 0; i < possibilities.length; i++) {
string = read(possibilities[i])
if (string) {
break
}
}
if (string === '+' && index > 1 && source[index - 2] === ' ') {
throw new Error('Space before `+`')
}
return string && {
type: 'OPERATOR',
string: string
}
}
function idstring () {
return read(/[A-Za-z0-9-.]+/)
}
function expectIdstring () {
var string = idstring()
if (!string) {
throw new Error('Expected idstring at offset ' + index)
}
return string
}
function documentRef () {
if (read('DocumentRef-')) {
var string = expectIdstring()
return { type: 'DOCUMENTREF', string: string }
}
}
function licenseRef () {
if (read('LicenseRef-')) {
var string = expectIdstring()
return { type: 'LICENSEREF', string: string }
}
}
function identifier () {
var begin = index
var string = idstring()
if (licenses.indexOf(string) !== -1) {
return {
type: 'LICENSE',
string: string
}
} else if (exceptions.indexOf(string) !== -1) {
return {
type: 'EXCEPTION',
string: string
}
}
index = begin
}
// Tries to read the next token. Returns `undefined` if no token is
// recognized.
function parseToken () {
// Ordering matters
return (
operator() ||
documentRef() ||
licenseRef() ||
identifier()
)
}
var tokens = []
while (hasMore()) {
skipWhitespace()
if (!hasMore()) {
break
}
var token = parseToken()
if (!token) {
throw new Error('Unexpected `' + source[index] +
'` at offset ' + index)
}
tokens.push(token)
}
return tokens
}