Perl One-liner de-compile?

Hi everyone,

Here is an example from the perlrun perldoc page:

perl -ane 'print pop(@F), "\n";'

is equivalent to
=20
while(<> ) {
@F =3D split(' ');
print pop(@F), "\n";
}


My question is, can I get Perl to evaluate a command line (like above)
and print out the equivalent code that command line will produce?

I hope that makes sense.  I thought I saw something similar to this on
this list before.

--Errin

On Mon, Apr 25, 2005 at 01:45:15PM -0500, Larsen, Errin M HMMA/IT wrote:

> Hi everyone,
>
>   Here is an example from the perlrun perldoc page:
>
>     perl -ane 'print pop(@F), "\n";'
>
>       is equivalent to
>
>     while(<> ) {
> 	@F = split(' ');
> 	print pop(@F), "\n";
>     }
>
>
>   My question is, can I get Perl to evaluate a command line (like above)
> and print out the equivalent code that command line will produce?
>
>   I hope that makes sense.  I thought I saw something similar to this on
> this list before.

$ perl -MO=Deparse -ane 'print pop(@F), "\n";'

--
Paul Johnson - paul@pjcj.net
http://www.pjcj.net

> -----Original Message-----
> From: Paul Johnson [mailto:paul@pjcj.net]=20
> Sent: Monday, April 25, 2005 1:53 PM
> To: Larsen, Errin M HMMA/IT
> Cc: beginners@perl.org
> Subject: Re: Perl One-liner de-compile?
>=20
>=20
> On Mon, Apr 25, 2005 at 01:45:15PM -0500, Larsen, Errin M=20
> HMMA/IT wrote:
>=20 
> similar to this=20 
>=20
> $ perl -MO=3DDeparse -ane 'print pop(@F), "\n";'
>=20
> --=20
> Paul Johnson - paul@pjcj.net
> http://www.pjcj.net
>=20


Ok ... So I tried this:

# perl -MO=3DDeparse -nae 'print $f[4]' /some/directory/somefile
LINE: while (defined($_ =3D <ARGV> )) {
our(@F) =3D split(" ", $_, 0);
print $f[4];
}
-e syntax OK

My question now is, where did the @f array come from?  I searched
through the perlvar perldoc page, but I only found an explanation for
the @F array.  Is this an example of Perl making a typo?  Or is the @f
array a secret array I'm not cleared to know about?

--Errin

Larsen, Errin M HMMA/IT <mailto:errinlarsen@hmmausa.com> wrote:

: Or is the @f array a secret array I'm not cleared to know about?


We could tell 'ya, but then we'd have to kill 'ya.

On Apr 25, Larsen, Errin M HMMA/IT said:
 

Note the @F, it's capital-F.

>  # perl -MO=Deparse -nae 'print $f[4]' /some/directory/somefile

You're using a lowercase @f here.

>  LINE: while (defined($_ = <ARGV> )) {
>      our(@F) = split(" ", $_, 0);
>      print $f[4];
>  }
>  -e syntax OK

Perl will magically produce the @F array for you, as shown.  It's up to
YOU not to make the typo.

--
Jeff "japhy" Pinyan         %  How can we ever be the sold short or
RPI Acacia Brother #734     %  the cheated, we who for every service
http://japhy.perlmonk.org/  %  have long ago been overpaid?
http://www.perlmonks.org/   %    -- Meister Eckhart

> -----Original Message-----
> From: Jeff 'japhy' Pinyan [mailto:japhy@perlmonk.org]=20
> Sent: Monday, April 25, 2005 2:42 PM
> To: Larsen, Errin M HMMA/IT
> Cc: beginners@perl.org
> Subject: RE: Perl One-liner de-compile?
>=20
<<SNIP>>
>=20
> You're using a lowercase @f here.
>=20
<<SNIP>>
>=20
> Perl will magically produce the @F array for you, as shown. =20
> It's up to=20
> YOU not to make the typo.
>=20


Ooops.  Hehe.

Thx for the 2nd set of eyes, Jeff.

--Errin

Larsen, Errin M HMMA/IT wrote:
>
> Ok ... So I tried this:
>
>   # perl -MO=Deparse -nae 'print $f[4]' /some/directory/somefile
^^^^^

>   LINE: while (defined($_ = <ARGV> )) {
>       our(@F) = split(" ", $_, 0);
>       print $f[4];
^^^^^

>   }
>   -e syntax OK
>
> My question now is, where did the @f array come from?  I searched
> through the perlvar perldoc page, but I only found an explanation for
> the @F array.  Is this an example of Perl making a typo?  Or is the @f
> array a secret array I'm not cleared to know about?

The @f array is there because YOU put it there.  Of course in this case it
will not contain anything.


John
--
use Perl;
program
fulfillment