I know this is a bit of topic but its still somewhat php related.
I am having difficulties with building the correct regular expression against which I test the input string with eregi function I need to check if the string i receive consists only of allowed characters and the square brackets [ ] something like that "^[0-9=+-]+$") plus those square brackets.
As far as I know I need to make this expression like this
"^[0-9=\[\]+-]+$") so I check if the string consists of one or more allowed characters.
This part of the expression is wrong \[\] (square brackets within square brackets)
What is the correct regular expression to match this pattern.
Thanks a lot.