[BNE-PM] Development Tools for Perl

[David Bussenschutt]

Give this man the one-liner award!     I love it!    So, does anyone else 
use perl to edit perl code? 

If the program edited itself, perhaps it could auto-rerun itself after the 
changes too.....

I've got code in my library of snippets that checks the checksum of a 
file, and I've got perl code that re-exec's itself on demand (usually 
after getting a kill -HUP signal), so why couldn't we easily have a perl 
program that re-exec's itself automatically whenever it determines that 
the code's checksum has changed?  Seems to me like a fun (if not 
potentially useful) thing to do...especially for "daemon" type code and 
the like where the process is always running.

 ;-)
David.
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David Bussenschutt        Email: D.Bussenschutt at mailbox.gu.edu.au
Senior Computing Support Officer & Systems Administrator/Programmer
RedHat Certified Engineer. 
Member of Systems Administrators Guild of Australia.
Location: Griffith University. Information Technology Services
           Brisbane Qld. Aust.  (TEN bldg. rm 1.33) Ph: (07)38757079
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Dean Povey <povey at wedgetail.com>
Sent by: owner-brisbane-pm-list at pm.org
18/12/2002 02:18 PM

 
        To:     Don.Simonetta at mincom.com
        cc:     brisbane-pm-list at happyfunball.pm.org
        Subject:        Re: [BNE-PM] Development Tools for Perl



>My tool of choice: gvim - graphical vim (improved vi).
>
>It has all the usual power of "vi" with an additional GUI front-end.
>There are many other features but the most obvious is the colouring for
>syntax recognition. It recognises a swag of languages including perl. It
>runs on both unix & win32 and the most important feature of all is its
>free! Available from http://www.vim.org

What! You don't use shell and perl one liners to edit your code?

1. Starting from scratch

$ cat <<EOF > helloworld.pl
#!/usr/bin/perl

print "This is my hello world pogram!\n";
EOF


2. Fixing a typo

$ perl -pi -e 's,pogram,program,' helloworld.pl

3. Inserting a line

$ perl -pi -e 'print "use strict;\n" if $. == 2;' helloworld.pl

4. Undo last change

$ mv helloworld.pl.bak helloworld.pl

5. Add a loop around the print statement

$ perl -pi -e 's,(^print .*;$),for my $i (0..100) {
> $1
> }
> ,' helloworld.pl


6. Indent the code
perl -pi -e '$t++ if $l =~ /{$/; $l=$_; $t-- if /}$/; print "    " x $t' \
                 helloworld.pl 

7. Delete various lines (in this case the 3rd and 5th lines)

$  perl -pi -e 'undef $_ if grep /^$.$/ (3,5)' helloworld.pl

8. Create an unrolled loop of 100 items

$ perl -pi -e 'print $_ x 100 if /print/' helloworld.pl

9. Change 20 of these items

$ perl -pi -e 's,\".*\","This is not my hello world program\\n", if $. >= 
10 \
                 && $. < 20' helloworld.pl

10. Display your code with line numbers

$ perl -p -e 'print "$.\t"' < helloworld.pl

11. Syntax highlight your code (Requires ANSI terminal

$  perl -p -e 
's,(\#.*$),\033[32m$1\033[0m,;s,(if|elsif|unless|else|while|for|foreach|do|until|continue|goto|return|last|next|redo|in|sub|my|local|die),\033[1;31m$1\033[0m,g 
unless 
/#|\"/;s,(push|pop|grep|map),\033[1;33m$1\033[0m,;s,(\"[^\"]*\"),\033[1;32m$1\033[0m,g 
unless /#|\"/' < helloworld.pl

And so on.... It is the only tool you need :-).