use strict;

print "

// Regex pattern below is automatically generated by regexpPrecederPatterns.pl

// Do not modify, your changes will be erased.

// CAVEAT: this does not properly handle the case where a regular

// expression immediately follows another since a regular expression may

// have flags for case-sensitivity and the like. Having regexp tokens

// adjacent is not valid in any language I'm aware of, so I'm punting.

// TODO: maybe style special characters inside a regexp as punctuation.

/**

* A set of tokens that can precede a regular expression literal in

* javascript

* http://web.archive.org/web/20070717142515/http://www.mozilla.org/js/language/js20/rationale/syntax.html

* has the full list, but I've removed ones that might be problematic when

* seen in languages that don't support regular expression literals.

*

* Specifically, I've removed any keywords that can't precede a regexp

* literal in a syntactically legal javascript program, and I've removed the

* \"in\" keyword since it's not a keyword in many languages, and might be used

* as a count of inches.

*

* The link above does not accurately describe EcmaScript rules since

* it fails to distinguish between (a=++/b/i) and (a++/b/i) but it works

* very well in practice.

*

* \@private

* \@const

*/

var REGEXP_PRECEDER_PATTERN = ";

my @preceders = (

"[!=]=?=?", # "!", "!=", "!==", "=", "==", "===",

"\\#",

"%=?", # "%", "%=",

"&&?=?", # "&", "&&", "&&=", "&=",

"\\(",

"\\*=?", # "*", "*=",

"[+\\-]=", # +=, -=. + and - handled below.

"->",

"\\/=?", # "/", "/=",

"::?", # ":", "::",

"<<?=?", # "<", "<<", "<<=", "<=",

">>?>?=?", # ">", ">=", ">>", ">>=", ">>>", ">>>=",

",",

";", # ";"

"\\?",

"@",

"\\[",

"~", # handles =~ and !~

"{",

"\\^\\^?=?", # "^", "^=", "^^", "^^=",

"\\|\\|?=?", # "|", "|=", "||", "||=",

"break", "case", "continue", "delete",

"do", "else", "finally", "instanceof",

"return", "throw", "try", "typeof"

);

# match at beginning, a dot that is not part of a number, or sign.

my $pattern = "'(?:^^\\\\.?|[+-]";

foreach my $preceder (@preceders) {

$preceder =~ s/\\/\\\\/g;

$pattern .= "|$preceder";

}

$pattern .= ")\\\\s*'"; # matches at end, and matches empty string

print "$pattern;\n";