66 lines
2.5 KiB
JavaScript
66 lines
2.5 KiB
JavaScript
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Prism.languages.racket = Prism.languages.extend('scheme', {
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'lambda-parameter': {
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// the racket lambda syntax is a lot more complex, so we won't even attempt to capture it.
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// this will just prevent false positives of the `function` pattern
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pattern: /(\(lambda\s+\()[^()'\s]+/,
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lookbehind: true
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}
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});
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// Add brackets to racket
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// The basic idea here is to go through all pattens of Scheme and replace all occurrences of "(" with the union of "("
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// and "["; Similar for ")". This is a bit tricky because "(" can be escaped or inside a character set. Both cases
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// have to be handled differently and, of course, we don't want to destroy groups, so we can only replace literal "("
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// and ")".
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// To do this, we use a regular expression which will parse any JS regular expression. It works because regexes are
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// matches from left to right and already matched text cannot be matched again. We use this to first capture all
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// escaped characters (not really, we don't get escape sequences but we don't need them). Because we already captured
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// all escaped characters, we know that any "[" character is the start of a character set, so we match that character
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// set whole.
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// With the regex parsed, we only have to replace all escaped "(" (they cannot be unescaped outside of character sets)
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// with /[([]/ and replace all "(" inside character sets.
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// Note: This method does not work for "(" that are escaped like this /\x28/ or this /\u0028/.
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Prism.languages.DFS(Prism.languages.racket, function (key, value) {
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if (Prism.util.type(value) === 'RegExp') {
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var source = value.source.replace(/\\(.)|\[\^?((?:\\.|[^\\\]])*)\]/g, function (m, g1, g2) {
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if (g1) {
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if (g1 === '(') {
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// replace all '(' characters outside character sets
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return '[([]';
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}
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if (g1 === ')') {
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// replace all ')' characters outside character sets
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return '[)\\]]';
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}
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}
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if (g2) {
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var prefix = m[1] === '^' ? '[^' : '[';
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return prefix + g2.replace(/\\(.)|[()]/g, function (m, g1) {
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if (m === '(' || g1 === '(') {
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// replace all '(' characters inside character sets
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return '([';
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}
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if (m === ')' || g1 === ')') {
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// replace all ')' characters inside character sets
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return ')\\]';
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}
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return m;
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}) + ']';
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}
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return m;
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});
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this[key] = RegExp(source, value.flags);
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}
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});
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Prism.languages.insertBefore('racket', 'string', {
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'lang': {
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pattern: /^#lang.+/m,
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greedy: true,
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alias: 'keyword'
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}
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});
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Prism.languages.rkt = Prism.languages.racket;
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