I have already expressed my support for this feature which IIRC existed in Libronix. This is a seriously geeky feature that would allow precise character by character searches and, if incorporated into Visual Filters, allow some of the odd filter requests we have seen recently.
From wikipedia:
[quote]
The phrase regular expressions (and consequently, regexps) is often used to mean the specific, standard textual syntax (distinct from the mathematical notation described below) for representing patterns that matching text need to conform to. Each character in a regular expression (that is, each character in the string describing its pattern) is understood to be: a metacharacter (with its special meaning), or a regular character (with its literal meaning). Together, they can be used to identify textual material of a given pattern, or process a number of instances of it. Pattern-matches can vary from a precise equality to a very general similarity (controlled by the metacharacters). The metacharacter syntax is designed specifically to represent prescribed targets in a concise and flexible way to direct the automation of text processing of a variety of input data, in a form easy to type using standard ASCII keyboard.
A very simple case of a regular expression in this syntax would be: to locate the same word spelled two different ways in a text editor, the regular expression seriali[sz]e matches both "serialise" and "serialize". Wildcards could also achieve this, but are more limited in what they can pattern (having fewer metacharacters and a simple language-base).
The usual context of wildcard characters is in globbing similar names in a list of files, whereas regexps are usually employed in applications that pattern-match text strings in general. For example, the regexp ^[ \t]+|[ \t]+$ matches excess whitespace at the beginning or end of a line. An advanced regexp used to match any numeral is ^[+-]?(\d+(\.\d+)?|\.\d+)([eE][+-]?\d+)?$. See Examples for more examples.
