/*
{

$re_parse()[.prop]

Takes in an mIRC regular expression and returns information
about it. Note the distinction between an mIRC regex and a
PCRE one: mIRC, being the application, interprets pattern
enclosing characters and modifiers. Thus the expressions that
this alias deals with are ones that are used, for example, in
$regex(), $regsub(), /filter -g, $hfind(), etc.

Properties:

.compiles - Returns $true if the pattern can be successfully
compiled by PCRE, $false otherwise.
.delimiter - Returns the pattern delimiter if one is used.
.exp - Returns the expression fed to the PCRE library,
excluding option setting verbs.
.modifiers - Returns the modifiers in the expression, if any.
.verbs - Returns the verbs at the start used to set options.
.all - Returns the name of a hash table containing results.

.all saves you having to re-call $re_parse() if you need a full
set of data. The hash table is filled with item names that match
the properties above, and the scripter should ensure to /hfree
the table when they are finished using it.

Without a property, it defaults to .compiles.

Examples:

• $re_parse(/abc/).exp = abc
• $re_parse(/abc[def/) = $false
• $re_parse(/\w+/ig).modifiers = ig
• $re_parse(m#abc#).delimiter = #

}
*/

alias re_parse {

  var %re = /(*UTF8) ^ (?| m(.?)|(/?) ) ( (?: \(\* (?:                      $&
    NO_START_OPT|CR|LF|CRLF|ANYCRLF|ANY|BSR_ANYCRLF|BSR_UNICODE|UTF8|UCP    $&
    ) \) )* ) (?| (.*)\1|(.*) ) (.*) /xs

  if (!$isutf($utfencode($1))) %re = 

  noop $regex(re_parse, $1, %re)

  if ($prop) {
    if ($prop $+ * iswm delimiter) returnex $regml(re_parse, 1)
    if ($v1 iswm verbs) return $regml(re_parse, 2)
    if ($v1 iswm exp) returnex $regml(re_parse, 3)

    var %m = [AEgimsSUxX]
    noop $regsub(re_parse2, $regml(re_parse, 4), /( %m )(*SKIP)(?= %m *\1)|.+/gsx, , %m)

    if ($v1 iswm modifiers) return %m
  }

  var %compiles = $istok($regex(,                                                  $&
    $+(/, $regml(re_parse, 2), |, $regml(re_parse, 3), /, $remove(%modifiers, g))  $&
    ), 1, 1)

  if ($v1 iswm all) {
    var %name

    ; "do/while in mIRC??" ;) just for fun
    :do {
      %name = re_parse $+ $rand(1, $not(0))
    }
    while ($hget(%name)) goto do

    hmake %name 10
    hadd %name compiles %compiles
    hadd %name delimiter $regml(re_parse, 1)
    hadd %name verbs $regml(re_parse, 2)
    hadd %name exp $regml(re_parse, 3)
    hadd %name modifiers %m

    return %name
  }

  if (!%re) return $false

  return %compiles
}