Core: Moved pattern matching + lookbehind logic into function (#2633)

PrismJS · Nov 25, 2020 · 2457440 · 2457440
1 parent 5cf9cfb
commit 2457440
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Showing 5 changed files with 92 additions and 62 deletions.
diff --git a/components/prism-core.js b/components/prism-core.js
@@ -823,6 +823,25 @@ Token.stringify = function stringify(o, language) {
 	return '<' + env.tag + ' class="' + env.classes.join(' ') + '"' + attributes + '>' + env.content + '</' + env.tag + '>';
 };
 
+/**
+ * @param {RegExp} pattern
+ * @param {number} pos
+ * @param {string} text
+ * @param {boolean} lookbehind
+ * @returns {RegExpExecArray | null}
+ */
+function matchPattern(pattern, pos, text, lookbehind) {
+	pattern.lastIndex = pos;
+	var match = pattern.exec(text);
+	if (match && lookbehind && match[1]) {
+		// change the match to remove the text matched by the Prism lookbehind group
+		var lookbehindLength = match[1].length;
+		match.index += lookbehindLength;
+		match[0] = match[0].slice(lookbehindLength);
+	}
+	return match;
+}
+
 /**
  * @param {string} text
  * @param {LinkedList<string | Token>} tokenList
@@ -855,7 +874,6 @@ function matchGrammar(text, tokenList, grammar, startNode, startPos, rematch) {
 				inside = patternObj.inside,
 				lookbehind = !!patternObj.lookbehind,
 				greedy = !!patternObj.greedy,
-				lookbehindLength = 0,
 				alias = patternObj.alias;
 
 			if (greedy && !patternObj.pattern.global) {
@@ -889,15 +907,15 @@ function matchGrammar(text, tokenList, grammar, startNode, startPos, rematch) {
 				}
 
 				var removeCount = 1; // this is the to parameter of removeBetween
+				var match;
 
 				if (greedy) {
-					pattern.lastIndex = pos;
-					var match = pattern.exec(text);
+					match = matchPattern(pattern, pos, text, lookbehind);
 					if (!match) {
 						break;
 					}
 
-					var from = match.index + (lookbehind && match[1] ? match[1].length : 0);
+					var from = match.index;
 					var to = match.index + match[0].length;
 					var p = pos;
 
@@ -931,24 +949,16 @@ function matchGrammar(text, tokenList, grammar, startNode, startPos, rematch) {
 					str = text.slice(pos, p);
 					match.index -= pos;
 				} else {
-					pattern.lastIndex = 0;
-
-					var match = pattern.exec(str);
-				}
-
-				if (!match) {
-					continue;
-				}
-
-				if (lookbehind) {
-					lookbehindLength = match[1] ? match[1].length : 0;
+					match = matchPattern(pattern, 0, str, lookbehind);
+					if (!match) {
+						continue;
+					}
 				}
 
-				var from = match.index + lookbehindLength,
-					matchStr = match[0].slice(lookbehindLength),
-					to = from + matchStr.length,
+				var from = match.index,
+					matchStr = match[0],
 					before = str.slice(0, from),
-					after = str.slice(to);
+					after = str.slice(from + matchStr.length);
 
 				var reach = pos + str.length;
 				if (rematch && reach > rematch.reach) {

diff --git a/components/prism-core.min.js b/components/prism-core.min.js
diff --git a/docs/global.html b/docs/global.html
@@ -143,7 +143,7 @@ <h4 class="name" id="Grammar">Grammar</h4>
 
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="prism-core.js.html">prism-core.js</a>, <a href="prism-core.js.html#line1161">line 1161</a>
+        <a href="prism-core.js.html">prism-core.js</a>, <a href="prism-core.js.html#line1171">line 1171</a>
     </li></ul></dd>
 
 
@@ -274,7 +274,7 @@ <h4 class="name" id="GrammarToken">GrammarToken</h4>
 
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="prism-core.js.html">prism-core.js</a>, <a href="prism-core.js.html#line1140">line 1140</a>
+        <a href="prism-core.js.html">prism-core.js</a>, <a href="prism-core.js.html#line1150">line 1150</a>
     </li></ul></dd>
 
 
@@ -559,7 +559,7 @@ <h4 class="name" id="HighlightCallback"><span class="type-signature"></span>High
 
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="prism-core.js.html">prism-core.js</a>, <a href="prism-core.js.html#line1169">line 1169</a>
+        <a href="prism-core.js.html">prism-core.js</a>, <a href="prism-core.js.html#line1179">line 1179</a>
     </li></ul></dd>
 
 
@@ -713,7 +713,7 @@ <h4 class="name" id="HookCallback"><span class="type-signature"></span>HookCallb
 
     <dt class="tag-source">Source:</dt>
     <dd class="tag-source"><ul class="dummy"><li>
-        <a href="prism-core.js.html">prism-core.js</a>, <a href="prism-core.js.html#line1179">line 1179</a>
+        <a href="prism-core.js.html">prism-core.js</a>, <a href="prism-core.js.html#line1189">line 1189</a>
     </li></ul></dd>