Distinguish keyword operations from math expressions.

int3 · int3 · commit ed58aec176a4 · 2011-05-17T23:36:52.000-04:00
In particular, we recognize `return /test/i` as returning a regular
expression, while `x /test/i` divides `x` by `test` and then by `i`.
diff --git a/syntax/javascript.vim b/syntax/javascript.vim
@@ -73,7 +73,7 @@ syntax match   javaScriptSpecial        "\\\d\d\d\|\\x\x\{2\}\|\\u\x\{4\}\|\\."
 syntax region  javaScriptStringD        start=+"+  skip=+\\\\\|\\$"+  end=+"+  contains=javaScriptSpecial,@htmlPreproc
 syntax region  javaScriptStringS        start=+'+  skip=+\\\\\|\\$'+  end=+'+  contains=javaScriptSpecial,@htmlPreproc
 syntax region  javaScriptRegexpCharClass start=+\[\]\|\[^\]\|\[+ end=+\]+ contained
-syntax region  javaScriptRegexpString   start=+\(\([)\]"']\|\d\|\w\)\s*\)\@<!/\(\*\|/\)\@!+ skip=+\\\\\|\\/+ end=+/[gim]\{,3}+ contains=javaScriptSpecial,javaScriptRegexpCharClass,@htmlPreproc oneline
+syntax region  javaScriptRegexpString   start=+\(\(\(return\|case\)\s\+\)\@<=\|\(\([)\]"']\|\d\|\w\)\s*\)\@<!\)/\(\*\|/\)\@!+ skip=+\\\\\|\\/+ end=+/[gim]\{,3}+ contains=javaScriptSpecial,javaScriptRegexpCharClass,@htmlPreproc oneline
 syntax match   javaScriptNumber         /\<-\=\d\+L\=\>\|\<0[xX]\x\+\>/
 syntax match   javaScriptFloat          /\<-\=\%(\d\+\.\d\+\|\d\+\.\|\.\d\+\)\%([eE][+-]\=\d\+\)\=\>/
 syntax match   javaScriptLabel          /\(?\s*\)\@<!\<\w\+\(\s*:\)\@=/
