perlquestion jmlynesjr <p>Monks:</p> <p>In cleaning up my More wxPerl Examples code in preparation to moving it to github, I came across several examples that use the switch construct. I want to update these to use the given-when construct. As seen below, I got a version to work, but there has to be a simpler/cleaner syntax. It seems to be something to do with (de)referencing the constant.</p> <p>Thanks in advance, James</p> <p>wxID_YES, wxID_NO, and wxID_CANCEL are wxPerl constants from <code>use Wx qw(:everything)</code>.</p> <p>Original working construct</p> <code>use switch; switch ($selection) { case wxID_YES {$self->Wx::LogStatus ("You pressed: \"Yes\" ")} case wxID_NO {$self->Wx::LogStatus ("You pressed: \"No\" ")} case wxID_CANCEL {$self->Wx::LogStatus ("You pressed: \"Cancel\" ")} }</code> <p>Replaced switch construct with given-when construct - fails, always takes Yes path</p> <code>given ($selection) { when (wxID_YES) {$self->Wx::LogStatus ("You pressed: \"Yes\" ")} when (wxID_NO) {$self->Wx::LogStatus ("You pressed: \"No\" ")} when (wxID_CANCEL) {$self->Wx::LogStatus ("You pressed: \"Cancel\" ")} }</code> <p>Working given-when construct</p> <code>given ($selection) { when ($_ == wxID_YES) {$self->Wx::LogStatus ("You pressed: \"Yes\" ")} when ($_ == wxID_NO) {$self->Wx::LogStatus ("You pressed: \"No\" ")} when ($_ == wxID_CANCEL) {$self->Wx::LogStatus ("You pressed: \"Cancel\" ")} }</code> <p>It also works if the constant is assigned to a scaler and then the scaler is used in the when clause.</p> <code>my $yes = wxID_YES; when ($yes) {....}</code> <b>Update1:</b> <p>Thanks to [Athanasius] for the great explanation and test code. I had seen the constant as subroutine construct, but didn't know how it worked in this case(hidden smart match). Thanks also to [tobyink]. The <code>when ([wxID_YES]) {....}</code> also works (why?) and seems cleaner than what I had come up with. I will go with the bracket construct. Thanks also to Anonymous Monk for the reference to the bug report.</p> <b>Update2:</b> <p>Thanks again to [Athanasius] and [tobyink]. The "why?" is now answered very clearly. I had tried <code>when ((wxID_YES))</code> and <code>when ({wxID_YES})</code>. I guess one more try and I wouldn't have asked the question and I still wouldn't have known why it worked! There are a lot of good teachers out there willing to share their time and knowledge. Thanks!</p>