* Gary Yang wrote: >I have hard time of understanding “use constant”. I do not understand >why place the “+” in front of constant variable. See the code below. In >the for loop, It adds “+” (+kAWSAccessKeyId,). In the new function call, >it adds the “+” (+RequestSignatureHelper::kAWSAccessKeyId => myAWSId). I >read the perldoc of “use constant”. But, no clue. Can someone explain >what it mean? Or point me any books or URLs I can read. I got the code >below from some samples. If this mailing list is not the proper place to >ask this question, please tell me which mailing list is best for this >question. Thanks.
This mailing list is dedicated to libwww-perl related issues, general questions about Perl programming would be better placed on forums like http://www.perlmonks.org/ or the comp.lang.perl.* newsgroups on Usenet. As for your question, many of the "+" in the script are redundant, so they are likely there for reasons of consistency. Sometimes you can use the operator to force a particular interpretation, for instance, print +('xxx'), ('yyy'); will print 'xxxyyy' but without the "+" you get 'xxx'. Similarily, >$self->{+kRequestMethod} The `constant.pm` module installs subroutines for the constants you register, so this is read as a function call $self->{ kRequestMethod() } while without the "+" it would be read as a string literal like $self->{ "kRequestMethod" } I hope that helps, -- Björn Höhrmann · mailto:bjo...@hoehrmann.de · http://bjoern.hoehrmann.de Am Badedeich 7 · Telefon: +49(0)160/4415681 · http://www.bjoernsworld.de 25899 Dagebüll · PGP Pub. KeyID: 0xA4357E78 · http://www.websitedev.de/
