Shell/POSIX/Select version 0.07 =============================== INSTALLATION To install this module type the following: perl Makefile.PL make test make install DEPENDENCIES This module requires these other modules and libraries: File::Spec::Functions Text::Balanced Filter::Simple ================================================================== NAME Shell::POSIX::Select - The POSIX Shell's "select" loop for Perl PURPOSE This module implements the "select" loop of the "POSIX" shells (Bash, Korn, and derivatives) for Perl. That loop is unique in two ways: it's by far the friendliest feature of any UNIX shell, and it's the *only* UNIX shell loop that's missing from the Perl language. Until now! SYNOPSIS NOTE: In the following, the enclosing square brackets (not typed) identify optional elements, and vertical bars indicate mutually-exclusive choices: select [[my|local|our<]> scalar_var] ( [LIST] ) { [CODE] } The required elements are the keyword "select", the *parentheses*, and the *curly braces*. See "SYNTAX" for details. ELEMENTARY EXAMPLE ship2me2.plx use Shell::POSIX::Select qw($Heading $Prompt); $Heading='Select a Shipper' ; $Prompt='Enter Vendor Number: ' ; select $shipper ( 'UPS', 'FedEx' ) { print "\nYou chose: $shipper\n"; last; } ship ($shipper, $ARGV[0]); # prints confirmation message OUTPUT ship2me2.plx '42 hemp toothbrushes' *Select a Shipper* 1) UPS 2) FedEx Enter Vendor Number: 2 You chose: FedEx Your order has been processed. Thanks for your business! BENEFITS What's so great about this loop? It automates the generation of a numbered menu of choices, prompts for a choice, proofreads that choice and complains if it's invalid (at least in this enhanced implementation), and executes a code-block with a variable set to the chosen value. That saves a lot of coding for interactive programs -- especially if the menu consists of many values! The benefit of bringing this loop to Perl is that it obviates the need for future programmers to reinvent the *Choose-From-A-Menu* wheel. EXPORTS: Default $Reply This variable is "local"ized to each "select" loop, and provides the menu-number of the most recent valid selection. EXPORTS: Optional $Heading $Prompt $Eof SCRIPTS browse_images browse_jpeg browse_records delete_file lc_filename long_listem menu_ls order perl_man pick pick_file AUTHOR Tim Maher MAINTAINER Martin Thurn mthurn@cpan.org ACKNOWLEDGEMENTS I probably never would have even attempted to write this module if it weren't for the provision of Filter::Simple by Damian Conway, which I ruthlessly exploited to make a hard job easy. *The Damian* also gave useful tips during the module's development, for which I'm grateful. I *definitely* wouldn't have ever written this module, if I hadn't found myself writing a chapter on *Looping* for my upcoming Manning Publications book, and once again lamenting the fact that the most friendly Shell loop was missing from Perl. In a fit of zeal, I decided to rectify that oversight! 8-} For more examples of how this loop can be used in Perl programs, watch for my upcoming book, *Minimal Perl: for Shell Users and Programmers* (see <http://teachmeperl.com/mp4sh.html>) in early fall, 2003. SEE ALSO man ksh # on UNIX or UNIX-like systems man bash # on UNIX or UNIX-like systems DON'T SEE ALSO perldoc -f select, which has nothing to do with this module (the names just happen to match up). LICENSE Copyright (C) 2002-2003, Timothy F. Maher. All rights reserved. This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.