(tye)Re: 'perl -p' ne 'cat'

[tye]

At first, I was thinking I could support "perl -p" (not in the #! line) giving a helpful message since it is expecting both its script and its input from STDIN. But I immediately thought of using a "TTY" as STDIN such that you can have two "ends of file" on the one STDIN:

shell> stty eof ^Z
shell> perl -p >>notes
BEGIN { print ''.localtime(),$/ } $_= "$.: $_"
CTRL-Z
Here are my notes for today.
I should really make this a real script.
CTRL-Z

But then I realized you can use __END__ to do this trick anywhere:

shell> cat script
$_= "$.: $_";
__END__
Testing
this.
shell> perl -p <script
1: Testing
2: this.

Granted, I haven't come up with a great use of this feature, but I'm reluctant to promote disabling it merely based on my lack of imagination. (:

        - tye (but my friends call me "Tye")

[danger]

I often add cases of test data after __END__ or __DATA__ in scripts that use while(<>) loops --- and I used to always switch between <> and <DATA> for testing purposes (and usually forgot to switch back when done). I recall being quite happy a few years back when I realized ("Doh!") I could just leave the bare diamond op and run the script on the test data via  perl -w < script.pl. Actually, I mostly test within the editor by sending the buffer to a filter of  perl -w with output directed to another buffer, but its the same thing.