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awk
Description
A looping construct for processing input in a way similar to the awk tool.
Author
Originally by Olin Shivers. This implementation has been taken from PLT Scheme's awk library and minimally modified by felix winkelmann to work with CHICKEN.
Requirements
None
Documentation
See the SCSH documentation for awk.
Examples
Count non-comment lines in Scheme file:
(use awk)
(print
(awk (read-line) (line) ([nlines 0])
("^[ \t]*;" nlines)
(else (add1 nlines))))Strip blank lines:
(use awk)
(awk (read-line) (line) ()
("[^ \t]" (print line)) )Compute maximal line length:
(use awk)
(print
(awk (read-line) (line) ([max-len 0])
(#t (max max-len (string-length line))))Sort /etc/passwd file:
(use awk)
(define (read-passwd . port)
(let ([line (apply read-line port)])
(if (eof-object? line)
(values line #f)
(values line (string-split-fields ":" line #:infix)))))
(for-each
(lambda (entry) (print (cdr entry)))
(sort
(awk (read-passwd) (line fields) ([ans '()])
(#t (cons (cons (car fields) line) ans)) )
(lambda (x y) (string<? (car x) (car y)))))Changelog
- 1.8 Fix license specification in the .meta file
- 1.7 Bugfix release thanks to Imran Rafique for the report
- 1.6 Updated test script to return proper exit status
- 1.4 Improved unit tests
- 1.3 Added regex dependency
- 1.2 Ported to CHICKEN 4
- 1.1 Adapted to new setup scheme
- 1.0 Initial release
License
PLT Software Copyright (c) 1995-2002 PLT
PLT software is distributed under the GNU Lesser General Public License (LGPL).