Excess =cut breaks module

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

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Re: Excess =cut breaks module by MidLifeXis (Monsignor) on Jan 20, 2012 at 17:05 UTC
The message I get when testing is `Foo.pm did not return a true value at -e line 1. BEGIN failed--compilation aborted at -e line 1.` [download] What this tells me is that the pod block was opened by the `=cut` directive, and is behaving as I would expect from my reading of perlpodspec. From perlpodspec, `Pod content is contained in Pod blocks. A Pod block starts with a line that matches m/\A=[a-zA-Z]/, and continues up to the next line that matches m/\A=cut/ or up to the end of the file if there is no m/\A=cut/ line.` Since you are not currently within a pod block when the stray `=cut` is encountered, it treats it as starting a pod block. The question then is if the specification should be changed, or left in its simpler form (a match of `m/\A=[a-zA-Z]/` starts a pod block, and the next `=cut` or end of file ends it). On the one hand, the current state requires that no stray `=cut` directives exist (at least if you expect the module to work as intended), and keeps the parser fairly simple. On the other hand, it sort of flies in the face of DWIMery. I ~~would probably~~ fall on the side of keeping the parser simple, and updating podchecker to check for this case (`=cut` starting a POD block), especially since it could actually indicate a missing start tag (code smell). Update: Firm up my position. --MidLifeXis	[reply] [d/l] [select]
Re^2: Excess =cut breaks module by Marshall (Canon) on Jan 20, 2012 at 17:51 UTC
At work, I would treat this as a "meets spec", "request to modify spec/or program" - and the lowest level of priority "bug tracking" (according to the impact). The "1;" at the end of a module is an executable statement! I think the OP got confused by the implications of this in an included module (the print statement in my test code perhaps makes it more clear what happens). I am ambivalent as to whether anything needs to or should be done about this. I would probably opt for a doc update "don't do that" in the description of =cut. This is malformed program syntax with a perhaps somewhat obscure symptom. I missed the details of what constitutes a "heading" in the specs, but my testing lead me to the same conclusion (the parser doesn't reject =cut as a "start of a block") based upon demonstrated behavior. When something "weird" is seen, often some very short test code can at least clarify what is happening.	[reply]
Re: Excess =cut breaks module by Marshall (Canon) on Jan 20, 2012 at 16:58 UTC
I was also able to replicate the problem. If you put 2 but not 3 "=cut" lines, it works. I guess somehow Perl figures that the first "=cut" is a heading. `#!/usr/bin/perl -w use strict; =cut =cut #=cut won't work with the 3rd one print "after the cut\n";` [download]	[reply] [d/l]
Re: Excess =cut breaks module by choroba (Cardinal) on Jan 20, 2012 at 16:53 UTC
According to the perlpod, `=cut` ends a pod block. From where do you get it should also start one?	[reply] [d/l]
Re: Excess =cut breaks module by Anonymous Monk on Jan 21, 2012 at 04:10 UTC
No, it is documented not to load, because its junk perl doesn't care how pod is started, only how it ends $ perldoc junk No documentation found for "junk". $ cat junk =cut =cut =cut print "what? \n"; __END__ $ perldoc junk No documentation found for "junk". $ perl junk $ perl -MO=Deparse junk junk syntax OK $ perl -MPod::Simple::Checker -e "exit Pod::Simple::Checker->filter(s +hift)->any_errata_seen" junk junk -- POD ERRORS Hey! The above document had some coding errors, which are explained be +low: Around line 1: =cut found outside a pod block. Skipping to next block. Around line 3: =cut found outside a pod block. Skipping to next block. Around line 5: =cut found outside a pod block. Skipping to next block. [download]	[reply] [d/l]