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List:       perl-beginners
Subject:    Re: Fwd: Is this code which is using Switch.pm safe?
From:       Chankey Pathak <chankey007 () gmail ! com>
Date:       2012-11-23 1:40:03
Message-ID: CA+PMQkG91MPS4gUg+=hUMbzhq92U1iqtd_q6zt0HSCMwTW8TLw () mail ! gmail ! com
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Sorry Paul,

I did that because I needed a quick reply, I won't do this again.



On Thu, Nov 22, 2012 at 1:09 PM, Paul Johnson <paul@pjcj.net> wrote:

> You asked exactly this question in both stackoverflow
> (
> http://stackoverflow.com/questions/13506511/is-this-code-which-is-using-switch-pm-safe
> )
> and perlmonks (http://perlmonks.org/?node_id=1005070).
>
> Please don't do that.  Or, if you think there is a good reason to do so,
> link to where you have previously posted.  Otherwise you are just
> wasting people's time.  By the time I answered your post here you
> already had a perfectly good answer on stackoverflow.
>
>
> On Thu, Nov 22, 2012 at 03:59:23PM +0530, Chankey Pathak wrote:
> > I discussed with the teammates and convinced them to go for 'dispatch
> > table'. Just want to know will the 'dispatch table' allow regex? As you
> can
> > see we're using regex in if-else part. I guess I'll have to use
> > Tie::RegexHash.
> >
> > Regarding the Perl version: I don't know when are they (my company) gonna
> > update it. I heard that we'll use 5.12 in the next update of our product
> > though.
> >
> >
> > On Thu, Nov 22, 2012 at 3:32 PM, Paul Johnson <paul@pjcj.net> wrote:
> >
> > > On Thu, Nov 22, 2012 at 11:37:15AM +0530, Chankey Pathak wrote:
> > > > In our company we were using this code (given at the end) for about
> 10
> > > > years and it worked fine.
> > > >
> > > > Some days ago we faced some issues and we had to re-code the complete
> > > > package, we decided to replace this code with Switch module by
> Damian (in
> > > > order to improve the readability of code).
> > > >
> > > > Everything is working fine for us.
> > > >
> > > > Later I found on Perlmonks <http://www.perlmonks.org/?node_id=486756
> >
> > > that
> > > > Damian had put this module under
> > > >
> > > > Damian modules you shouldn't use in production because their purpose
> is
> > > to
> > > > explore and prototype future core language features.
> > > >
> > > > But it is working fine for us because we are not hitting the
> limitations
> > > of
> > > > this module (I guess).
> > > >
> > > > Now I ask you guys to please have a look at the both implementations
> > > > (nested if else vs switch) and let me know whether using Switch in
> the
> > > > newer implementation is fine or are we creating some future problems
> for
> > > > us? Is using Switch in the code given below fine or are there any
> hidden
> > > > bugs/problems?
> > > >
> > > > I've already read the bugs and reviews of this module on CPAN and
> > > Perlmonks
> > > > and I guess our code is far away from hitting those bugs (I think
> so).
> > > >
> > > > We are using Perl 5.8.5.
> > > >
> > > > *PS:* I know the alternatives of Switch, we have given/when in Perl
> 5.10,
> > > > we can use dispatch table and other solutions which are specified
> > > > here<
> > >
> http://stackoverflow.com/questions/844616/obtain-a-switch-case-behaviour-in-perl-5
> > > >,
> > > > but right now we just want to compare the new implementation which
> uses
> > > > Switch.
> > > >
> > > >
> > > > Code:
> > > >
> > > > *Using nested if else: http://paste.debian.net/211434/*
> > > >
> > > > *Using Switch: http://paste.debian.net/211435/*
> > >
> > > Hmmm.  Is it safe?  I suppose that depends on what you mean by that.
>  If
> > > it works in the conditions you care about I suppose you could say it is
> > > safe.
> > >
> > > > or are we creating some future problems
> > >
> > > That's very possible.  Or perhaps it will run for ten years before
> > > someone else does a rewrite.
> > >
> > > I'm not sure why, knowing what you obviously do, you are wedded to
> using
> > > Switch.  I would be trying to use a dispatch table, if the case
> > > insensitivity of $command would allow it.  Failing that, I see nothing
> > > particularly unreadable about the if/elsif/else chain.  Especially if
> > > you make the bodies into sepatate subs so you only have one sub call
> per
> > > condition.  Then you could line everything up vertically to make it
> very
> > > readable.
> > >
> > > Even if you update your perl version I would stay away from given/when
> > > for now.
> > >
> > > And you should update your perl version.  It's unsuported, buggy and
> I'm
> > > sure it has security problems which have been fixed in the last eight
> > > years.  (That's always a good case to make to management folk.)
> > >
> > > --
> > > Paul Johnson - paul@pjcj.net
> > > http://www.pjcj.net
> > >
> >
> >
> >
> > --
> > Regards,
> > Chankey Pathak <http://www.linuxstall.com>
>
> --
> Paul Johnson - paul@pjcj.net
> http://www.pjcj.net
>



-- 
Regards,
Chankey Pathak <http://www.linuxstall.com>


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