regexp matching with a $string

[stilllearning]

I have a $string that contains a bunch of special characters that regexp will pick up as expressions... so how can I do...

if {[regexp $string $matchstring]} { ... }

since that won't work, what i am looking for is a way to negate expressions like \. for a period but for the entire $string to make it literal.

[Ofloo]

This is a proc that will return <number of special chars> on special chars and 0 on alphabetic and nummeric chars..

Code: Select all

proc special {arg} {
  if {[regexp -nocase -all {[^a-z0-9]} $string -> n]} {
    return $n
  }
  return 0
}