flow like the river

VISUALIZACION/node_modules/regexpu-core/rewrite-pattern.js

@@ -0,0 +1,193 @@
+var generate = require('regjsgen').generate;
+var parse = require('regjsparser').parse;
+var regenerate = require('regenerate');
+var iuMappings = require('./data/iu-mappings.json');
+var ESCAPE_SETS = require('./data/character-class-escape-sets.js');
+
+function getCharacterClassEscapeSet(character) {
+	if (unicode) {
+		if (ignoreCase) {
+			return ESCAPE_SETS.UNICODE_IGNORE_CASE[character];
+		}
+		return ESCAPE_SETS.UNICODE[character];
+	}
+	return ESCAPE_SETS.REGULAR[character];
+}
+
+var object = {};
+var hasOwnProperty = object.hasOwnProperty;
+function has(object, property) {
+	return hasOwnProperty.call(object, property);
+}
+
+// Prepare a Regenerate set containing all code points, used for negative
+// character classes (if any).
+var UNICODE_SET = regenerate().addRange(0x0, 0x10FFFF);
+// Without the `u` flag, the range stops at 0xFFFF.
+// https://mths.be/es6#sec-pattern-semantics
+var BMP_SET = regenerate().addRange(0x0, 0xFFFF);
+
+// Prepare a Regenerate set containing all code points that are supposed to be
+// matched by `/./u`. https://mths.be/es6#sec-atom
+var DOT_SET_UNICODE = UNICODE_SET.clone() // all Unicode code points
+	.remove(
+		// minus `LineTerminator`s (https://mths.be/es6#sec-line-terminators):
+		0x000A, // Line Feed <LF>
+		0x000D, // Carriage Return <CR>
+		0x2028, // Line Separator <LS>
+		0x2029  // Paragraph Separator <PS>
+	);
+// Prepare a Regenerate set containing all code points that are supposed to be
+// matched by `/./` (only BMP code points).
+var DOT_SET = DOT_SET_UNICODE.clone()
+	.intersection(BMP_SET);
+
+// Add a range of code points + any case-folded code points in that range to a
+// set.
+regenerate.prototype.iuAddRange = function(min, max) {
+	var $this = this;
+	do {
+		var folded = caseFold(min);
+		if (folded) {
+			$this.add(folded);
+		}
+	} while (++min <= max);
+	return $this;
+};
+
+function assign(target, source) {
+	for (var key in source) {
+		// Note: `hasOwnProperty` is not needed here.
+		target[key] = source[key];
+	}
+}
+
+function update(item, pattern) {
+	// TODO: Test if memoizing `pattern` here is worth the effort.
+	if (!pattern) {
+		return;
+	}
+	var tree = parse(pattern, '');
+	switch (tree.type) {
+		case 'characterClass':
+		case 'group':
+		case 'value':
+			// No wrapping needed.
+			break;
+		default:
+			// Wrap the pattern in a non-capturing group.
+			tree = wrap(tree, pattern);
+	}
+	assign(item, tree);
+}
+
+function wrap(tree, pattern) {
+	// Wrap the pattern in a non-capturing group.
+	return {
+		'type': 'group',
+		'behavior': 'ignore',
+		'body': [tree],
+		'raw': '(?:' + pattern + ')'
+	};
+}
+
+function caseFold(codePoint) {
+	return has(iuMappings, codePoint) ? iuMappings[codePoint] : false;
+}
+
+var ignoreCase = false;
+var unicode = false;
+function processCharacterClass(characterClassItem) {
+	var set = regenerate();
+	var body = characterClassItem.body.forEach(function(item) {
+		switch (item.type) {
+			case 'value':
+				set.add(item.codePoint);
+				if (ignoreCase && unicode) {
+					var folded = caseFold(item.codePoint);
+					if (folded) {
+						set.add(folded);
+					}
+				}
+				break;
+			case 'characterClassRange':
+				var min = item.min.codePoint;
+				var max = item.max.codePoint;
+				set.addRange(min, max);
+				if (ignoreCase && unicode) {
+					set.iuAddRange(min, max);
+				}
+				break;
+			case 'characterClassEscape':
+				set.add(getCharacterClassEscapeSet(item.value));
+				break;
+			// The `default` clause is only here as a safeguard; it should never be
+			// reached. Code coverage tools should ignore it.
+			/* istanbul ignore next */
+			default:
+				throw Error('Unknown term type: ' + item.type);
+		}
+	});
+	if (characterClassItem.negative) {
+		set = (unicode ? UNICODE_SET : BMP_SET).clone().remove(set);
+	}
+	update(characterClassItem, set.toString());
+	return characterClassItem;
+}
+
+function processTerm(item) {
+	switch (item.type) {
+		case 'dot':
+			update(
+				item,
+				(unicode ? DOT_SET_UNICODE : DOT_SET).toString()
+			);
+			break;
+		case 'characterClass':
+			item = processCharacterClass(item);
+			break;
+		case 'characterClassEscape':
+			update(
+				item,
+				getCharacterClassEscapeSet(item.value).toString()
+			);
+			break;
+		case 'alternative':
+		case 'disjunction':
+		case 'group':
+		case 'quantifier':
+			item.body = item.body.map(processTerm);
+			break;
+		case 'value':
+			var codePoint = item.codePoint;
+			var set = regenerate(codePoint);
+			if (ignoreCase && unicode) {
+				var folded = caseFold(codePoint);
+				if (folded) {
+					set.add(folded);
+				}
+			}
+			update(item, set.toString());
+			break;
+		case 'anchor':
+		case 'empty':
+		case 'group':
+		case 'reference':
+			// Nothing to do here.
+			break;
+		// The `default` clause is only here as a safeguard; it should never be
+		// reached. Code coverage tools should ignore it.
+		/* istanbul ignore next */
+		default:
+			throw Error('Unknown term type: ' + item.type);
+	}
+	return item;
+};
+
+module.exports = function(pattern, flags) {
+	var tree = parse(pattern, flags);
+	ignoreCase = flags ? flags.indexOf('i') > -1 : false;
+	unicode = flags ? flags.indexOf('u') > -1 : false;
+	assign(tree, processTerm(tree));
+	return generate(tree);
+};