https://docs.angularjs.org/components/google-code-prettify-1.0.1/src/lang-css.js

1// Copyright (C) 2009 Google Inc.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//      http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15
16
17/**
18 * @fileoverview
19 * Registers a language handler for CSS.
20 *
21 *
22 * To use, include prettify.js and this file in your HTML page.
23 * Then put your code in an HTML tag like
24 *      <pre class="prettyprint lang-css"></pre>
25 *
26 *
27 * http://www.w3.org/TR/CSS21/grammar.html Section G2 defines the lexical
28 * grammar.  This scheme does not recognize keywords containing escapes.
29 *
30 * @author [email protected]
31 */
32
33// This file is a call to a function defined in prettify.js which defines a
34// lexical scanner for CSS and maps tokens to styles.
35
36// The call to PR['registerLangHandler'] is quoted so that Closure Compiler
37// will not rename the call so that this language extensions can be
38// compiled/minified separately from one another.  Other symbols defined in
39// prettify.js are similarly quoted.
40
41// The call is structured thus:
42// PR['registerLangHandler'](
43//    PR['createSimpleLexer'](
44//        shortcutPatterns,
45//        fallThroughPatterns),
46//    [languageId0, ..., languageIdN])
47
48// Langugage IDs
49// =============
50// The language IDs are typically the file extensions of source files for
51// that language so that users can syntax highlight arbitrary files based
52// on just the extension.  This is heuristic, but works pretty well in
53// practice.
54
55// Patterns
56// ========
57// Lexers are typically implemented as a set of regular expressions.
58// The SimpleLexer function takes regular expressions, styles, and some
59// pragma-info and produces a lexer.  A token description looks like
60//   [STYLE_NAME, /regular-expression/, pragmas]
61
62// Initially, simple lexer's inner loop looked like:
63
64//    while sourceCode is not empty:
65//      try each regular expression in order until one matches
66//      remove the matched portion from sourceCode
67
68// This was really slow for large files because some JS interpreters
69// do a buffer copy on the matched portion which is O(n*n)
70
71// The current loop now looks like
72
73//    1. use js-modules/combinePrefixPatterns.js to 
74//       combine all regular expressions into one 
75//    2. use a single global regular expresion match to extract all tokens
76//    3. for each token try regular expressions in order until one matches it
77//       and classify it using the associated style
78
79// This is a lot more efficient but it does mean that lookahead and lookbehind
80// can't be used across boundaries to classify tokens.
81
82// Sometimes we need lookahead and lookbehind and sometimes we want to handle
83// embedded language -- JavaScript or CSS embedded in HTML, or inline assembly
84// in C.
85
86// If a particular pattern has a numbered group, and its style pattern starts
87// with "lang-" as in
88//    ['lang-js', /<script>(.*?)<\/script>/]
89// then the token classification step breaks the token into pieces.
90// Group 1 is re-parsed using the language handler for "lang-js", and the
91// surrounding portions are reclassified using the current language handler.
92// This mechanism gives us both lookahead, lookbehind, and language embedding.
93
94// Shortcut Patterns
95// =================
96// A shortcut pattern is one that is tried before other patterns if the first
97// character in the token is in the string of characters.
98// This very effectively lets us make quick correct decisions for common token
99// types.
100
101// All other patterns are fall-through patterns.
102
103
104
105// The comments inline below refer to productions in the CSS specification's
106// lexical grammar.  See link above.
107PR['registerLangHandler'](
108    PR['createSimpleLexer'](
109        // Shortcut patterns.
110        [
111         // The space production <s>
112         [PR['PR_PLAIN'],       /^[ \t\r\n\f]+/, null, ' \t\r\n\f']
113        ],
114        // Fall-through patterns.
115        [
116         // Quoted strings.  <string1> and <string2>
117         [PR['PR_STRING'],
118          /^\"(?:[^\n\r\f\\\"]|\\(?:\r\n?|\n|\f)|\\[\s\S])*\"/, null],
119         [PR['PR_STRING'],
120          /^\'(?:[^\n\r\f\\\']|\\(?:\r\n?|\n|\f)|\\[\s\S])*\'/, null],
121         ['lang-css-str', /^url\(([^\)\"\']+)\)/i],
122         [PR['PR_KEYWORD'],
123          /^(?:url|rgb|\!important|@import|@page|@media|@charset|inherit)(?=[^\-\w]|$)/i,
124          null],

125         // A property name -- an identifier followed by a colon.
126         ['lang-css-kw', /^(-?(?:[_a-z]|(?:\\[0-9a-f]+ ?))(?:[_a-z0-9\-]|\\(?:\\[0-9a-f]+ ?))*)\s*:/i],
127         // A C style block comment.  The <comment> production.
128         [PR['PR_COMMENT'], /^\/\*[^*]*\*+(?:[^\/*][^*]*\*+)*\//],
129         // Escaping text spans
130         [PR['PR_COMMENT'], /^(?:<!--|-->)/],
131         // A number possibly containing a suffix.
132         [PR['PR_LITERAL'], /^(?:\d+|\d*\.\d+)(?:%|[a-z]+)?/i],
133         // A hex color
134         [PR['PR_LITERAL'], /^#(?:[0-9a-f]{3}){1,2}\b/i],
135         // An identifier
136         [PR['PR_PLAIN'],
137          /^-?(?:[_a-z]|(?:\\[\da-f]+ ?))(?:[_a-z\d\-]|\\(?:\\[\da-f]+ ?))*/i],
138         // A run of punctuation
139         [PR['PR_PUNCTUATION'], /^[^\s\w\'\"]+/]
140        ]),
141    ['css']);
142// Above we use embedded languages to highlight property names (identifiers
143// followed by a colon) differently from identifiers in values.
144PR['registerLangHandler'](
145    PR['createSimpleLexer']([],
146        [
147         [PR['PR_KEYWORD'],
148          /^-?(?:[_a-z]|(?:\\[\da-f]+ ?))(?:[_a-z\d\-]|\\(?:\\[\da-f]+ ?))*/i]
149        ]),
150    ['css-kw']);
151// The content of an unquoted URL literal like url(http://foo/img.png) should
152// be colored as string content.  This language handler is used above in the
153// URL production to do so.
154PR['registerLangHandler'](
155    PR['createSimpleLexer']([],
156        [
157         [PR['PR_STRING'], /^[^\)\"\']+/]
158        ]),
159    ['css-str']);