FunctionPackage: exclToCDocOverviewCGDocRelNotesFAQIndexPermutedIndex
Allegro CL version 10.1
Unrevised from 10.0 to 10.1.
10.0 version


Arguments: regexp string indexes selector &key (type :string)

This is a convenience function to extract a specified submatch information from the value returned by match-re.

regexp should be a compiled regexp, and indexes should be a list of (start . end) index pairs returned by match-re. selector should be an integer that specifies a captured submatch (or 0 for the whole match), or a string or a symbol that names a named submatch.

Alternatively, you can pass the opaque 'match' object returned by match-re with :return :match argument, as regexp. The match object knows the information about the match results, so you don't need string and indexes; just pass nil to them.

The type argument may be :string, :after, :before or :index. It specifies the return value. If it is :string (the default), the substring of the specified submatch is returned. If it is :after or :before, the substring after or before the specified submatch is returned, respectively. If it is :index, a pair of (start . end) indexes are returned.

If the specified submatch isn't included in indexes, nil is returned.

A typical usage pattern of this function is like this:

(let ((r (multiple-value-list (match-re regexp string :return :index))))
  (re-submatch regexp string (cdr r) 3)))

Or, if you use the match object, like this:

(let ((match (match-re regexp string :return :match)))
  (re-submatch match nil nil 3))

Additional examples

cl-user(25): (let* ((s "abCDEfg")
                    (x (compile-re "[A-Z]([A-Z]+)"))
                    (r (cdr (multiple-value-list
                             (match-re x s :return :index)))))
                (re-submatch x s r 0)
                (re-submatch x s r 1)
                (re-submatch x s r 0 :type :before)
                (re-submatch x s r 1 :type :before)
                (re-submatch x s r 0 :type :after)
                (re-submatch x s r 1 :type :after)))
("CDE" "DE" "ab" "abC" "fg" "fg")

The symbol naming this operator is also exported from the regexp package.

See The new regexp2 module in regexp.htm for further information on this function and the regexp2 module.

Copyright (c) 1998-2022, Franz Inc. Lafayette, CA., USA. All rights reserved.
This page was not revised from the 10.0 page.
Created 2019.8.20.

Allegro CL version 10.1
Unrevised from 10.0 to 10.1.
10.0 version