Returns a random string based on inputted information.

/*
URL  : www.hirc.org / www.mircmalaysia.com
email: da-hype@hirc.org
Thanks to Sigh_ for helping me improve code.

Returns a random string.
Usage: $_randstring(flags,length)
Flags:
n - numbers
l - lowercase
u - uppercase
c - other ascii characters
*/
alias _randstring {
  var %i = 1,%flag = $1,%n = $2,%x,%s
  ;checks for invalid flags
  if (n !isin %flag) && (l !isin %flag) && (u !isin %flag) && (c !isin %flag) _err Unknown flags: %flag
  ;checks for invalid integers
  if (%n !isnum) || (%n < 1) _err Invalid integer: %n
  ;limits max %n to 900
  if (%n > 900) %n = 900
  ;loops threw flags and randomize
  while (%i <= %n) {
    %s = $replacex(%flag,n,$r(1,9),l,$r(a,z),u,$r(A,Z),c,$chr($r(126,255)))
    %x = $+(%x,$mid(%s,$r(1,$len(%s)),1))
    inc %i
  }
  ;returns value
  if (%x) return %x
  else halt
}
alias -l _err {
  var %a = $+(,$color(info text)) $+ ERROR: <command>
  echo -a $replace(%a,<command>,$1-)
}