eval() and INIT{}

powerman has asked for the wisdom of the Perl Monks concerning the following question:

Hi! I've just found what INIT{} and CHECK{} blocks ignored in eval(). I've not found information about this behaviour in docs, so this may be a bug. What do you think about this?

$ perl -le '
print 1;
INIT { print 2 }
END { print 3 }
BEGIN { print 4 }
CHECK { print 5 }
'
4
5
2
1
3

$ perl -le 'eval "
print 1;
INIT { print 2 }
END { print 3 }
BEGIN { print 4 }
CHECK { print 5 }
 "'
4
1
3
[download]

Comment on eval() and INIT{} Download Code

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use warnings;
by PodMaster (Abbot) on Mar 28, 2004 at 13:56 UTC

C:\dev\LOOSE>cat s
eval "
print 1;
INIT { print 2 }
END { print 3 }
BEGIN { print 4 }
CHECK { print 5 }
 ";
print "out of eval $@";
C:\dev\LOOSE>perl -Wl s
Too late to run INIT block at (eval 1) line 3.
4
Too late to run CHECK block at (eval 1) line 6.
1
out of eval
3
[download]

MJD says "you can't just make shit up and expect the computer to know what you mean, retardo!"
I run a Win32 PPM repository for perl 5.6.x and 5.8.x -- I take requests (README).
** The third rule of perl club is a statement of fact: pod is sexy.

[reply]
[d/l]

Re: eval() and INIT{}
by calin (Deacon) on Mar 28, 2004 at 14:03 UTC

Try running with warnings enabled:

$ perl -wle 'eval "
print 1;
INIT { print 2 }
END { print 3 }
BEGIN { print 4 }
CHECK { print 5 }

"'
Too late to run INIT block at (eval 1) line 3.
4
Too late to run CHECK block at (eval 1) line 6.
1
3
[download]

What happens is that "string eval" code is compiled after the run-time has been initialised, therefore it's too late for INIT/CHECK mechanism.

[reply]
[d/l]

Re: eval() and INIT{}
by diotalevi (Canon) on Mar 29, 2004 at 03:47 UTC

You won't see this if you do your evals during BEGIN, before the once-only INIT has happened.

[reply]