Expansion of the Festival Regex tools

Festival Regex: ``string-matches''

The Scheme function ``string-matches'' provides an interface to handle regular expressions. It takes a string and a regular expression and returns true if they match.

Expansion: ``pattern-matches''

The function ``pattern-matches'' extends the functionality of ``string-matches''. It binds the substrings to variables (like in perl). As real pattern matching takes a rather long time, this is just a simple implementation which only considers the longest match. The pattern has a slightly different structure compared to ``string-matches'':

.	matches any character
$	matches the end of a string
^	matches the beginning of a string
X*	matches none or several occurances of X
X+	matches one or more occurances of X
X?	matches one or none occurance
[ ]	matches a range (e.g. [abc],[a-zäöüß], [^abc] means neither
	a nor b nor c)
\\(...\\)	parenthesized expressions are handled like single characters.
	This way '*', '+', '?', ...may be applied to more than
	just single characters.
X\\ Y	matches either X or Y
{ ...}	for each bracketed expression a new variable is generated.
	It is tied to the part of the string which matches the regular
	expression within curly brackets. The variables are
	#1, #2, ... starting from the left.

Here is a short example:
(pattern-matches "9pfünder" "{[0-9]+}{[a-zäöüß]+}")
returns true (t) and ties ``9'' to variable #1 and ``pfünder'' to variable #2.