157 lines
3.7 KiB
JavaScript
157 lines
3.7 KiB
JavaScript
/**
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* Methods for consuming quoted values
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*/
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const SINGLE_QUOTE = 39; // '
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const DOUBLE_QUOTE = 34; // "
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const defaultOptions = {
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escape: 92, // \ character
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throws: false
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};
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/**
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* Consumes 'single' or "double"-quoted string from given string, if possible
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* @param {StreamReader} stream
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* @param {Number} options.escape A character code of quote-escape symbol
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* @param {Boolean} options.throws Throw error if quotes string can’t be properly consumed
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* @return {Boolean} `true` if quoted string was consumed. The contents
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* of quoted string will be availabe as `stream.current()`
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*/
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var eatQuoted = function(stream, options) {
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options = options ? Object.assign({}, defaultOptions, options) : defaultOptions;
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const start = stream.pos;
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const quote = stream.peek();
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if (stream.eat(isQuote)) {
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while (!stream.eof()) {
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switch (stream.next()) {
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case quote:
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stream.start = start;
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return true;
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case options.escape:
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stream.next();
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break;
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}
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}
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// If we’re here then stream wasn’t properly consumed.
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// Revert stream and decide what to do
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stream.pos = start;
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if (options.throws) {
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throw stream.error('Unable to consume quoted string');
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}
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}
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return false;
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};
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function isQuote(code) {
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return code === SINGLE_QUOTE || code === DOUBLE_QUOTE;
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}
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/**
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* Check if given code is a number
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* @param {Number} code
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* @return {Boolean}
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*/
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function isNumber(code) {
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return code > 47 && code < 58;
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}
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/**
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* Check if given character code is alpha code (letter through A to Z)
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* @param {Number} code
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* @param {Number} [from]
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* @param {Number} [to]
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* @return {Boolean}
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*/
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function isAlpha(code, from, to) {
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from = from || 65; // A
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to = to || 90; // Z
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code &= ~32; // quick hack to convert any char code to uppercase char code
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return code >= from && code <= to;
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}
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/**
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* Check if given character code is alpha-numeric (letter through A to Z or number)
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* @param {Number} code
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* @return {Boolean}
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*/
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function isAlphaNumeric(code) {
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return isNumber(code) || isAlpha(code);
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}
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function isWhiteSpace(code) {
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return code === 32 /* space */
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|| code === 9 /* tab */
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|| code === 160; /* non-breaking space */
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}
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/**
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* Check if given character code is a space
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* @param {Number} code
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* @return {Boolean}
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*/
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function isSpace(code) {
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return isWhiteSpace(code)
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|| code === 10 /* LF */
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|| code === 13; /* CR */
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}
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const defaultOptions$1 = {
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escape: 92, // \ character
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throws: false
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};
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/**
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* Eats paired characters substring, for example `(foo)` or `[bar]`
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* @param {StreamReader} stream
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* @param {Number} open Character code of pair openinig
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* @param {Number} close Character code of pair closing
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* @param {Object} [options]
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* @return {Boolean} Returns `true` if chacarter pair was successfully
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* consumed, it’s content will be available as `stream.current()`
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*/
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function eatPair(stream, open, close, options) {
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options = options ? Object.assign({}, defaultOptions$1, options) : defaultOptions$1;
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const start = stream.pos;
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if (stream.eat(open)) {
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let stack = 1, ch;
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while (!stream.eof()) {
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if (eatQuoted(stream, options)) {
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continue;
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}
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ch = stream.next();
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if (ch === open) {
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stack++;
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} else if (ch === close) {
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stack--;
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if (!stack) {
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stream.start = start;
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return true;
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}
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} else if (ch === options.escape) {
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stream.next();
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}
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}
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// If we’re here then paired character can’t be consumed
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stream.pos = start;
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if (options.throws) {
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throw stream.error(`Unable to find matching pair for ${String.fromCharCode(open)}`);
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}
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}
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return false;
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}
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export { eatQuoted, isQuote, isAlpha, isNumber, isAlphaNumeric, isSpace, isWhiteSpace, eatPair };
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