y return $calc($1 + $2 + $3)
remv {
  var %x $3
  if ($4 isnum) var %x $4,%y $3
  return $regsubex($1,/( $+ $2 $+ )/ig,$iif(\n = %x || %x = 0,%y,\1))
}
x return $y($len($1),$2,$3)
rep return $remv($1,$2,$3,$4)
del return $remv($1,.,$iif($2 > 0,$2,$x($1,$2,1)))
put {
  noop $regex($1,/(.{ $+ $a($1,$3) $+ })(.{ $+ $len($2) $+ })?(.*)/)
  return $+($regml(1),$2,$regml(3))
}
a return $iif($2 > 0,$y($2,-1),$x($1,$2))
ins { var %y $2
  return $regsubex($1,.{ $+ $a($1,$3) $+ }\K,\1%y\2)
}