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From: merlyn@iwarp.intel.com (Randal Schwartz)
Newsgroups: comp.lang.perl
Subject: Re: StreamPerl (Was Re: Randal's one-liners)
Message-ID: <1990Mar10.015518.4776@iwarp.intel.com>
Date: 10 Mar 90 01:55:18 GMT
References: <JV.90Mar9110239@squirrel.mh.nl>
Sender: news@iwarp.intel.com
Reply-To: merlyn@iwarp.intel.com (Randal Schwartz)
Organization: Stonehenge; netaccess via Intel, Beaverton, Oregon, USA
Lines: 73
In-Reply-To: jv@mh.nl (Johan Vromans)

In article <JV.90Mar9110239@squirrel.mh.nl>, jv@mh (Johan Vromans) writes:
| I found the following perl program very helpful in exercizing Randal's
| one-liners: 
| 
|   #!/usr/bin/perl
|   eval "exec perl -S $0 $*"
|     if $running_under_some_shell;
|   #
|   # StreamPerl - execute perl program from standard input
|   #
|   ($version,$patchlevel) = $] =~ /(\d+.\d+).*\nPatch level: (\d+)/;
|   print "StreamPerl version $version, patchlevel $patchlevel\n";
| 
|   $prog = "/usr/tmp/spl$$";
|   open (TMP, ">$prog") || die "Cannot create $prog, stopped";
| 
|   print TMP while <STDIN>;
|   close TMP;
| 
|   do $prog;
| 
|   unlink ($prog);

Izzer something wrong with:

	some_process_that_generates_perl | perl

instead of your script above?  That's how *I* execute fragments from
news postings.  (I use GNU Emacs to read news, so I just mark a
fragment as a region, then feed the region as stdin to Perl.  In fact,
the sequence "mark-region", ESC-| perl <ret>, is very much locked into
my fingers... especially while attacking a new .sig. :-)
	
| In addition, the following program, based on the idea of a perl shell,
| has proven very helpful on trying perl:
| 
|   #!/usr/local/bin/perl
|   eval "exec perl -S $0 $*"
|     if $running_under_some_shell;
| 
|   ($version,$patchlevel) = $] =~ /(\d+.\d+).*\nPatch level: (\d+)/;
|   print "Interactive Perl version $version, patchlevel $patchlevel\n";
| 
|   $Prompt = 'perl> ';
|   $Printing = "\n";
|   print $Prompt;
|   while (<stdin>) {
|     $Pres = eval $_ . ';';
|     print $Pres.$Printing if $Printing;
|     print $@;
|     print $Prompt;
|   }

This is very similar to 'perlsh' in the old distribution.  I now do
something a *whole* lot simpler:

perl -de '0;'

Yup.  That's right.  Debug a simple program given on the command line.
Larry was even going to look at removing the need for the semicolon in
a command line '-e' switch (ala 'eval'), so I could just type:

perl -de 0

but that didn't make it into Patch 9 from who-knows-where.  Maybe
Patch 13 (the one that fixes the debugger...? :-).

printf "%c"x 25,74,117,115,116,32,97,110,111,116,104,101,114,32,80,101,114,108,32,104,97,99,107,101,114,44;
-- 
/=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\
| on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III      |
| merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn |
\=Cute Quote: "Welcome to Portland, Oregon, home of the California Raisins!"=/