Question

Everything in this code works properly, except the contents of the $1 variable aren’t being properly displayed. According to my tests, all the matching is being done properly, I am just having trouble figuring out how to actually output the contents of $1.

  codeTags = {
              /\[b\](.+?)\[\/b\]/m => "<strong>#{$1}</strong>",
              /\[i\](.+?)\[\/i\]/m => "<em>#{$1}</em>"
             }

             regexp = Regexp.new(/(#{Regexp.union(codeTags.keys)})/)
             message = (message).gsub(/#{regexp}/) do |match|
               codeTags[codeTags.keys.select {|k| match =~ Regexp.new(k)}[0]]
             end

  return message.html_safe

Thank you!

Answer 1

As soon as you do this:

codeTags = {
    /\[b\](.+?)\[\/b\]/m => "<strong>#{$1}</strong>",
    /\[i\](.+?)\[\/i\]/m => "<em>#{$1}</em>"
}

The #{$1} bits in the values are interpolated using whatever happens to be in $1 at the time. The values will most likely be "<strong></strong>" and "<em></em>" and those aren’t very useful.

And regexp is already a regular expression object so gsub(/#{regexp}/) should be just gsub(regexp). Similar things apply to the keys of codeTags, they’re already regular expression objects so you don’t need to Regexp.new(k).

I’d change the whole structure, you’re overcomplicating things. Just something simple like this would be fine for only two replacements:

message = message.gsub(/\[b\](.*?)\[\/b\]/) { '<strong>' + $1 + '</strong>' }
message = message.gsub(/\[i\](.*?)\[\/i\]/) { '<em>'     + $1 + '</em>'     }

If you try to do it all at once you’ll have problems with nesting in something like this:

message = 'Where [b]is[/b] pancakes [b]house [i]and[/i] more[/b] stuff?'

You’d end up having to use a recursive gsub and possibly some lambdas if you wanted to properly handle things like that with a single expression.

There are better things to spend your time on than trying to be clever on something like this.

Response to comments: If you have more bb-tags and some smilies to worry about and several messages per page then you should HTMLify each message when you create it. You could store only the HTML version or both HTML and BB-Code versions if you want the BB-Code stuff around for some reason. This way you’d only pay for the HTMLification once per message and producing your big lists would be nearly free.