package libparse-recdescent-perl tags 297921 upstream forwarded 297921 [EMAIL PROTECTED] thanks
* Marcin Owsiany <[EMAIL PROTECTED]> [2005-03-03 15:55]: > Package: libparse-recdescent-perl > Version: 1.94-1 > Severity: minor > > Hi! > > The tutorial mentions multiple times returning values from actions. One > things it fails to mention is that calling return in an action is > completly different from setting $return or just specifying the value as > the last statement. See the attached example, and see the attached diff > file for how removing the "return" changes the output. This is all the > more difficult to debug, that the message: > > >>Matched subrule: [gallery]<< (return value: [1] > > is present even in the failing case, even though the parser retracts to > the beginning, as the third column suggests. So it's somewhat > misleading. > > This has taken me several long hours to find out (in a more complicated > grammar), and I really would like to make this one thing more visible in > the documentation, so that noone will have to waste his time again. > > regards, > > Marcin I do not know how we can fix the "bug" reported here. The mentioned tutorial document is the online version of an article published in the Perl Journal. Your proposal is to change that HTML document, but I am not sure what I am allowed to do with it. I am forwarding this bug report to Damian Conway, the upstream author. Damian, do you think that we can change the tutorial in the Debian package? If this is possible, here is a request for the bug submitter (Marcin Owsiany): could you please prepare a patch according to what you think it should be changed in the tutorial? Here is the extra information in the original bug report (also available at http://bugs.debian.org/297921): > -- System Information: > Debian Release: 3.1 > APT prefers unstable > APT policy: (500, 'unstable'), (1, 'experimental') > Architecture: i386 (i686) > Kernel: Linux 2.4.27-2-k7 > Locale: LANG=pl_PL, LC_CTYPE=pl_PL (charmap=ISO-8859-2) > > Versions of packages libparse-recdescent-perl depends on: > ii perl 5.8.4-6 Larry Wall's Practical > Extraction > > -- no debconf information > --- a_test 2005-03-03 15:35:42.000000000 +0100 > +++ a_test_no_return 2005-03-03 15:36:09.000000000 +0100 > @@ -12,7 +12,7 @@ > > gallery: 'gallery' label '{' desc(s) '}' ';' > { > - return 1; > + 1; > } > > desc: 'desc' '"' /[^"]*/ '"' ';' { $item[3] } > Script started on czw 03 mar 2005 15:38:49 CET > ]0;[EMAIL PROTECTED]: /home/porridge/[EMAIL PROTECTED]:~/tmp$ ./a_de > test > Parse::RecDescent: Treating "config:" as a rule declaration > Parse::RecDescent: Treating "gallery" as a subrule match > Parse::RecDescent: Treating "EE" as a literal terminal > Parse::RecDescent: Treating "gallery:" as a rule declaration > Parse::RecDescent: Treating "gallery" as a literal terminal > Parse::RecDescent: Treating "label" as a subrule match > Parse::RecDescent: Treating "{" as a literal terminal > Parse::RecDescent: Treating "desc(s)" as a one-or-more subrule match > Parse::RecDescent: Treating "}" as a literal terminal > Parse::RecDescent: Treating ";" as a literal terminal > Parse::RecDescent: Treating "{ return 1; }" as an action > Parse::RecDescent: Treating "desc:" as a rule declaration > Parse::RecDescent: Treating "desc" as a literal terminal > Parse::RecDescent: Treating """ as a literal terminal > Parse::RecDescent: Treating "/[^"]*/" as a /../ pattern terminal > Parse::RecDescent: Treating """ as a literal terminal > Parse::RecDescent: Treating ";" as a literal terminal > Parse::RecDescent: Treating "{ $item[3] }" as an action > Parse::RecDescent: Treating "label:" as a rule declaration > Parse::RecDescent: Treating "/\w+/" as a /../ pattern terminal > printing code (22472) to RD_TRACE > 1| config |Trying rule: [config] | > 1| config | |"gallery exim { desc > "foo"; > | | |}; EE" > 1| config |Trying production: [gallery 'EE'] | > 1| config |Trying subrule: [gallery] | > 2| gallery |Trying rule: [gallery] | > 2| gallery |Trying production: ['gallery' label | > | |'{' desc '}' ';'] | > 2| gallery |Trying terminal: ['gallery'] | > 2| gallery |>>Matched terminal<< (return value: | > | |[gallery]) | > 2| gallery | |" exim { desc "foo"; }; > EE" > 2| gallery |Trying subrule: [label] | > 3| label |Trying rule: [label] | > 3| label |Trying production: [/\w+/] | > 3| label |Trying terminal: [/\w+/] | > 3| label |>>Matched terminal<< (return value: | > | |[exim]) | > 3| label | |" { desc "foo"; }; EE" > 3| label |>>Matched production: [/\w+/]<< | > 3| label |>>Matched rule<< (return value: | > | |[exim]) | > 3| label |(consumed: [ exim]) | > 2| gallery |>>Matched subrule: [label]<< (return | > | |value: [exim] | > 2| gallery |Trying terminal: ['{'] | > 2| gallery |>>Matched terminal<< (return value: | > | |[{]) | > 2| gallery | |" desc "foo"; }; EE" > 2| gallery |Trying repeated subrule: [desc] | > 3| desc |Trying rule: [desc] | > 3| desc |Trying production: ['desc' '"' /[^"]*/| > | |'"' ';'] | > 3| desc |Trying terminal: ['desc'] | > 3| desc |>>Matched terminal<< (return value: | > | |[desc]) | > 3| desc | |" "foo"; }; EE" > 3| desc |Trying terminal: ['"'] | > 3| desc |>>Matched terminal<< (return value: | > | |["]) | > 3| desc | |"foo"; }; EE" > 3| desc |Trying terminal: [/[^"]*/] | > 3| desc |>>Matched terminal<< (return value: | > | |[foo]) | > 3| desc | |""; }; EE" > 3| desc |Trying terminal: ['"'] | > 3| desc |>>Matched terminal<< (return value: | > | |["]) | > 3| desc | |"; }; EE" > 3| desc |Trying terminal: [';'] | > 3| desc |>>Matched terminal<< (return value: | > | |[;]) | > 3| desc | |" }; EE" > 3| desc |Trying action | > 3| desc |>>Matched action<< (return value: | > | |[foo]) | > 3| desc |>>Matched production: ['desc' '"' | > | |/[^"]*/ '"' ';']<< | > 3| desc |>>Matched rule<< (return value: [foo])| > 3| desc |(consumed: [ desc "foo";]) | > 3| desc |Trying rule: [desc] | > 3| desc |Trying production: ['desc' '"' /[^"]*/| > | |'"' ';'] | > 3| desc |Trying terminal: ['desc'] | > 3| desc |<<Didn't match terminal>> | > 3| desc | |"}; EE" > 3| desc |<<Didn't match rule>> | > 2| gallery |>>Matched repeated subrule: [desc]<< | > | |(1 times) | > 2| gallery | |" }; EE" > 2| gallery |Trying terminal: ['}'] | > 2| gallery |>>Matched terminal<< (return value: | > | |[}]) | > 2| gallery | |"; EE" > 2| gallery |Trying terminal: [';'] | > 2| gallery |>>Matched terminal<< (return value: | > | |[;]) | > 2| gallery | |" EE" > 2| gallery |Trying action | > 1| config |>>Matched subrule: [gallery]<< (return| > | |value: [1] | > 1| config | |"gallery exim { desc > "foo"; > | | |}; EE" > 1| config |Trying terminal: ['EE'] | > 1| config |<<Didn't match terminal>> | > 1| config |<<Didn't match rule>> | > parse returned undef > ]0;[EMAIL PROTECTED]: /home/porridge/[EMAIL PROTECTED]:~/tmp$ > Script done on czw 03 mar 2005 15:38:55 CET > Script started on czw 03 mar 2005 15:39:28 CET > ]0;[EMAIL PROTECTED]: /home/porridge/[EMAIL PROTECTED]:~/tmp$ > ./a_test_no_return > Parse::RecDescent: Treating "config:" as a rule declaration > Parse::RecDescent: Treating "gallery" as a subrule match > Parse::RecDescent: Treating "EE" as a literal terminal > Parse::RecDescent: Treating "gallery:" as a rule declaration > Parse::RecDescent: Treating "gallery" as a literal terminal > Parse::RecDescent: Treating "label" as a subrule match > Parse::RecDescent: Treating "{" as a literal terminal > Parse::RecDescent: Treating "desc(s)" as a one-or-more subrule match > Parse::RecDescent: Treating "}" as a literal terminal > Parse::RecDescent: Treating ";" as a literal terminal > Parse::RecDescent: Treating "{ 1; }" as an action > Parse::RecDescent: Treating "desc:" as a rule declaration > Parse::RecDescent: Treating "desc" as a literal terminal > Parse::RecDescent: Treating """ as a literal terminal > Parse::RecDescent: Treating "/[^"]*/" as a /../ pattern terminal > Parse::RecDescent: Treating """ as a literal terminal > Parse::RecDescent: Treating ";" as a literal terminal > Parse::RecDescent: Treating "{ $item[3] }" as an action > Parse::RecDescent: Treating "label:" as a rule declaration > Parse::RecDescent: Treating "/\w+/" as a /../ pattern terminal > printing code (22465) to RD_TRACE > 1| config |Trying rule: [config] | > 1| config | |"gallery exim { desc > "foo"; > | | |}; EE" > 1| config |Trying production: [gallery 'EE'] | > 1| config |Trying subrule: [gallery] | > 2| gallery |Trying rule: [gallery] | > 2| gallery |Trying production: ['gallery' label | > | |'{' desc '}' ';'] | > 2| gallery |Trying terminal: ['gallery'] | > 2| gallery |>>Matched terminal<< (return value: | > | |[gallery]) | > 2| gallery | |" exim { desc "foo"; }; > EE" > 2| gallery |Trying subrule: [label] | > 3| label |Trying rule: [label] | > 3| label |Trying production: [/\w+/] | > 3| label |Trying terminal: [/\w+/] | > 3| label |>>Matched terminal<< (return value: | > | |[exim]) | > 3| label | |" { desc "foo"; }; EE" > 3| label |>>Matched production: [/\w+/]<< | > 3| label |>>Matched rule<< (return value: | > | |[exim]) | > 3| label |(consumed: [ exim]) | > 2| gallery |>>Matched subrule: [label]<< (return | > | |value: [exim] | > 2| gallery |Trying terminal: ['{'] | > 2| gallery |>>Matched terminal<< (return value: | > | |[{]) | > 2| gallery | |" desc "foo"; }; EE" > 2| gallery |Trying repeated subrule: [desc] | > 3| desc |Trying rule: [desc] | > 3| desc |Trying production: ['desc' '"' /[^"]*/| > | |'"' ';'] | > 3| desc |Trying terminal: ['desc'] | > 3| desc |>>Matched terminal<< (return value: | > | |[desc]) | > 3| desc | |" "foo"; }; EE" > 3| desc |Trying terminal: ['"'] | > 3| desc |>>Matched terminal<< (return value: | > | |["]) | > 3| desc | |"foo"; }; EE" > 3| desc |Trying terminal: [/[^"]*/] | > 3| desc |>>Matched terminal<< (return value: | > | |[foo]) | > 3| desc | |""; }; EE" > 3| desc |Trying terminal: ['"'] | > 3| desc |>>Matched terminal<< (return value: | > | |["]) | > 3| desc | |"; }; EE" > 3| desc |Trying terminal: [';'] | > 3| desc |>>Matched terminal<< (return value: | > | |[;]) | > 3| desc | |" }; EE" > 3| desc |Trying action | > 3| desc |>>Matched action<< (return value: | > | |[foo]) | > 3| desc |>>Matched production: ['desc' '"' | > | |/[^"]*/ '"' ';']<< | > 3| desc |>>Matched rule<< (return value: [foo])| > 3| desc |(consumed: [ desc "foo";]) | > 3| desc |Trying rule: [desc] | > 3| desc |Trying production: ['desc' '"' /[^"]*/| > | |'"' ';'] | > 3| desc |Trying terminal: ['desc'] | > 3| desc |<<Didn't match terminal>> | > 3| desc | |"}; EE" > 3| desc |<<Didn't match rule>> | > 2| gallery |>>Matched repeated subrule: [desc]<< | > | |(1 times) | > 2| gallery | |" }; EE" > 2| gallery |Trying terminal: ['}'] | > 2| gallery |>>Matched terminal<< (return value: | > | |[}]) | > 2| gallery | |"; EE" > 2| gallery |Trying terminal: [';'] | > 2| gallery |>>Matched terminal<< (return value: | > | |[;]) | > 2| gallery | |" EE" > 2| gallery |Trying action | > 2| gallery |>>Matched action<< (return value: [1])| > 2| gallery |>>Matched production: ['gallery' label| > | |'{' desc '}' ';']<< | > 2| gallery |>>Matched rule<< (return value: [1]) | > 2| gallery |(consumed: [gallery exim { desc "foo";| > | |};]) | > 1| config |>>Matched subrule: [gallery]<< (return| > | |value: [1] | > 1| config |Trying terminal: ['EE'] | > 1| config |>>Matched terminal<< (return value: | > | |[EE]) | > 1| config |>>Matched production: [gallery 'EE']<<| > 1| config |>>Matched rule<< (return value: [EE]) | > 1| config |(consumed: []) | > ?:$VAR1 = 'EE'; > ]0;[EMAIL PROTECTED]: /home/porridge/[EMAIL PROTECTED]:~/tmp$ > Script done on czw 03 mar 2005 15:39:34 CET > --- parser1 2005-03-03 15:38:55.000000000 +0100 > +++ parser2 2005-03-03 15:39:34.000000000 +0100 > @@ -10,7 +10,7 @@ > Parse::RecDescent: Treating "desc(s)" as a one-or-more subrule match > Parse::RecDescent: Treating "}" as a literal terminal > Parse::RecDescent: Treating ";" as a literal terminal > - Parse::RecDescent: Treating "{ return 1; }" as an action > + Parse::RecDescent: Treating "{ 1; }" as an action > Parse::RecDescent: Treating "desc:" as a rule declaration > Parse::RecDescent: Treating "desc" as a literal terminal > Parse::RecDescent: Treating """ as a literal terminal > @@ -20,7 +20,7 @@ > Parse::RecDescent: Treating "{ $item[3] }" as an action > Parse::RecDescent: Treating "label:" as a rule declaration > Parse::RecDescent: Treating "/\w+/" as a /../ pattern terminal > -printing code (22472) to RD_TRACE > +printing code (22465) to RD_TRACE > 1| config |Trying rule: [config] | > 1| config | |"gallery exim { desc > "foo"; > | | |}; EE" > @@ -100,13 +100,20 @@ > | |[;]) | > 2| gallery | |" EE" > 2| gallery |Trying action | > + 2| gallery |>>Matched action<< (return value: [1])| > + 2| gallery |>>Matched production: ['gallery' label| > + | |'{' desc '}' ';']<< | > + 2| gallery |>>Matched rule<< (return value: [1]) | > + 2| gallery |(consumed: [gallery exim { desc "foo";| > + | |};]) | > 1| config |>>Matched subrule: [gallery]<< (return| > | |value: [1] | > - 1| config | |"gallery exim { desc > "foo"; > - | | |}; EE" > 1| config |Trying terminal: ['EE'] | > - 1| config |<<Didn't match terminal>> | > - 1| config |<<Didn't match rule>> | > -parse returned undef > + 1| config |>>Matched terminal<< (return value: | > + | |[EE]) | > + 1| config |>>Matched production: [gallery 'EE']<<| > + 1| config |>>Matched rule<< (return value: [EE]) | > + 1| config |(consumed: []) | > +?:$VAR1 = 'EE'; > ]0;[EMAIL PROTECTED]: /home/porridge/[EMAIL PROTECTED]:~/tmp$ -- Rafael
