Regular expression question

So I'm trying to implement a simple wiki-like syntax for hyperlinking. Basically I want to match stuff like [this], where the word 'this' gets turned into a hyperlink. I have that working, but I want to be able to escape the opening bracket, so that it's possible to do \[that] without having it match as a link. Here's what I've got: // Matches fine, but without escaping $pattern = "

    /
        \[          # Open bracket
        ([^\]]+?)   # Text, including whitespace
        \]          # Close bracket
    /x

"; // Throws an unmatched bracket warning $pattern = "

    /
        [^\\]       # Don't match if a backslash precedes
        \[          # Open bracket
        ([^\]]+?)   # Text, including whitespace
        \]          # Close bracket
    /x

"; // Ignores escaping: \[example] still matches $pattern = "

    /
        [^\\\]      # Don't match if a backslash precedes
        \[          # Open bracket
        ([^\]]+?)   # Text, including whitespace
        \]          # Close bracket
    /x

"; Nothing seems to change if I keep adding backslashes to that first matching thingy (i.e. the escaping still doesn't work). Any ideas? Thanks much, -Dan