pregexp.scm is a portable library for
regular expressions (aka regexps or
regexes) that runs in any Scheme
that complies with R4RS, R5RS or R6RS [2]. It
provides regular expressions
modeled on
Perl’s [1, 3], and includes such
powerful directives as numeric and nongreedy
quantifiers, capturing and non-capturing clustering,
POSIX character classes, selective case- and
space-insensitivity, backreferences, alternation,
backtrack pruning,
positive and negative lookahead and lookbehind, in
addition to the more basic directives familiar to all
regexp users.
To use, simply load the file pregexp.scm into
your Scheme.
(Alternatively, if your dialect allows it, you can
install pregexp as a module — consult
the file
INSTALL in the distribution.)
The file pregexp.lisp is the Common Lisp version
of this library. To use it, load it into your Common Lisp.
(The descriptions and examples in this manual use Scheme
syntax, but their
translation to CL syntax is trivial.)
Contents
2 Regexp procedures
2.1 pregexp
2.2 pregexp‑match‑positions
2.3 pregexp‑match
2.4 pregexp‑split
2.5 pregexp‑replace
2.6 pregexp‑replace*
2.7 pregexp‑quote
3 The regexp pattern language
3.1 Basic assertions
3.2 Characters and character classes
3.2.1 Some frequently used character
classes
3.2.2 POSIX character classes
3.3 Quantifiers
3.3.1 Numeric quantifiers
3.3.2 Non-greedy quantifiers
3.4 Clusters
3.4.1 Backreferences
3.4.2 Non-capturing clusters
3.4.3 Cloisters
3.5 Alternation
3.6 Backtracking
3.6.1 Disabling backtracking
3.7 Looking ahead and behind
3.7.1 Lookahead
3.7.2 Lookbehind