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cpp: Fully support C++11 raw strings. #1897

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Feb 3, 2019
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45 changes: 43 additions & 2 deletions src/highlight.js
Original file line number Diff line number Diff line change
Expand Up @@ -237,6 +237,47 @@ https://highlightjs.org/
);
}

// joinRe logically computes regexps.join(separator), but fixes the
// backreferences so they continue to match.
function joinRe(regexps, separator) {
// backreferenceRe matches an open parenthesis or backreference. To avoid
// an incorrect parse, it additionally matches the following:
// - [...] elements, where the meaning of parentheses and escapes change
// - other escape sequences, so we do not misparse escape sequences as
// interesting elements
// - non-matching or lookahead parentheses, which do not capture. These
// follow the '(' with a '?'.
var backreferenceRe = /\[(?:[^\\\]]|\\.)*\]|\(\??|\\([1-9][0-9]*)|\\./;
var numCaptures = 0;
var ret = '';
for (var i = 0; i < regexps.length; i++) {
var offset = numCaptures;
var re = reStr(regexps[i]);
if (i > 0) {
ret += separator;
}
while (re.length > 0) {
var match = backreferenceRe.exec(re);
if (match == null) {
ret += re;
break;
}
ret += re.substring(0, match.index);
re = re.substring(match.index + match[0].length);
if (match[0][0] == '\\' && match[1]) {
// Adjust the backreference.
ret += '\\' + String(Number(match[1]) + offset);
} else {
ret += match[0];
if (match[0] == '(') {
numCaptures++;
}
}
}
}
return ret;
}

function compileMode(mode, parent) {
if (mode.compiled)
return;
Expand Down Expand Up @@ -302,12 +343,12 @@ https://highlightjs.org/

var terminators =
mode.contains.map(function(c) {
return c.beginKeywords ? '\\.?(' + c.begin + ')\\.?' : c.begin;
return c.beginKeywords ? '\\.?(?:' + c.begin + ')\\.?' : c.begin;
})
.concat([mode.terminator_end, mode.illegal])
.map(reStr)
.filter(Boolean);
mode.terminators = terminators.length ? langRe(terminators.join('|'), true) : {exec: function(/*s*/) {return null;}};
mode.terminators = terminators.length ? langRe(joinRe(terminators, '|'), true) : {exec: function(/*s*/) {return null;}};
}

compileMode(language);
Expand Down
8 changes: 1 addition & 7 deletions src/languages/cpp.js
Original file line number Diff line number Diff line change
Expand Up @@ -19,13 +19,7 @@ function(hljs) {
illegal: '\\n',
contains: [hljs.BACKSLASH_ESCAPE]
},
{
// TODO: This does not handle raw string literals with prefixes. Using
// a single regex with backreferences would work (note to use *?
// instead of * to make it non-greedy), but the mode.terminators
// computation in highlight.js breaks the counting.
begin: '(u8?|U|L)?R"\\(', end: '\\)"',
},
{ begin: /(?:u8?|U|L)?R"([^()\\ ]{0,16})\((?:.|\n)*?\)\1"/ },
{
begin: '\'\\\\?.', end: '\'',
illegal: '.'
Expand Down
34 changes: 30 additions & 4 deletions test/markup/cpp/string-literals.expect.txt
Original file line number Diff line number Diff line change
Expand Up @@ -10,21 +10,47 @@
<span class="hljs-comment">// Raw string literals (multiline)</span>
<span class="hljs-keyword">auto</span> char_multi = <span class="hljs-string">R"(Hello
"normal"
muliline
multiline
string.)"</span>;
<span class="hljs-keyword">auto</span> utf8_multi = <span class="hljs-string">u8R"(Hello
"utf-8"
muliline
multiline
string)"</span>;
<span class="hljs-keyword">auto</span> utf16_multi = <span class="hljs-string">uR"(Hello
"utf-16"
muliline
multiline
string)"</span>;
<span class="hljs-keyword">auto</span> utf32_multi = <span class="hljs-string">UR"(Hello
"utf-32"
muliline
multiline
string)"</span>;

<span class="hljs-comment">// Raw string literals with delimiter (multiline)</span>
<span class="hljs-keyword">auto</span> char_multi = <span class="hljs-string">R"blah1(Hello
"normal"
multiline
)"
)blah"
string.)blah1"</span>;
<span class="hljs-keyword">auto</span> utf8_multi = <span class="hljs-string">u8R"blah2(Hello
"utf-8"
multiline
)"
)blah"
string)blah2"</span>;
<span class="hljs-keyword">auto</span> utf16_multi = <span class="hljs-string">uR"blah3(Hello
"utf-16"
multiline
)"
)blah"
string)blah3"</span>;
<span class="hljs-keyword">auto</span> utf32_multi = <span class="hljs-string">UR"blah4(Hello
"utf-32"
multiline
)"
)blah"
string)blah4"</span>;

<span class="hljs-comment">// Meta strings</span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span> <span class="hljs-meta-string">&lt;stdio&gt;</span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span> <span class="hljs-meta-string">"lib.h"</span></span>
34 changes: 30 additions & 4 deletions test/markup/cpp/string-literals.txt
Original file line number Diff line number Diff line change
Expand Up @@ -10,21 +10,47 @@ auto wide_char = L"Hello wchar_t string";
// Raw string literals (multiline)
auto char_multi = R"(Hello
"normal"
muliline
multiline
string.)";
auto utf8_multi = u8R"(Hello
"utf-8"
muliline
multiline
string)";
auto utf16_multi = uR"(Hello
"utf-16"
muliline
multiline
string)";
auto utf32_multi = UR"(Hello
"utf-32"
muliline
multiline
string)";

// Raw string literals with delimiter (multiline)
auto char_multi = R"blah1(Hello
"normal"
multiline
)"
)blah"
string.)blah1";
auto utf8_multi = u8R"blah2(Hello
"utf-8"
multiline
)"
)blah"
string)blah2";
auto utf16_multi = uR"blah3(Hello
"utf-16"
multiline
)"
)blah"
string)blah3";
auto utf32_multi = UR"blah4(Hello
"utf-32"
multiline
)"
)blah"
string)blah4";

// Meta strings
#include <stdio>
#include "lib.h"