Re: [gentoo-dev] evar_push/pop helpers

[Mike Frysinger <vapier@gentoo.org>]

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On Sunday 02 June 2013 03:16:53 Michał Górny wrote:
> Dnia 2013-06-02, o godz. 03:09:31 Mike Frysinger napisał(a):
> > On Sunday 02 June 2013 02:51:34 Michał Górny wrote:
> > > Dnia 2013-06-01, o godz. 23:03:20 Mike Frysinger napisał(a):
> > > > simple set of helpers to save/restore a variable in a limited section
> > > > of code
> > > > 
> > > > you can see an example of it in action at the end of the file where i
> > > > need to tweak epatch (and no, doing `LC_COLLATE=C set -- ....` does
> > > > not work).
> > > 
> > > Why the ugly hackery instead of proper 'local' scope?
> > 
> > there's no way to undo the local thus it affects the rest of the func. 
> > this makes sure the change is actually localized to where it is needed.
> 
> By use of global variables and a bunch of additional code and evals.

the implementation details of estack_* doesn't matter

> Is:
> 
>   local _epatch_foo=${foo}
>   local foo
>   ...
>   foo=${_epatch_foo}
> 
> really that hurtful?

except you aren't handling edge cases (like set vs unset), and i've replicated 
this pattern before (in fact, you've filed bugs where the set/unset case wasn't 
handled).  API 101: implement it once correctly to simplify everyone else.

> Also, do you really want the collation to be changed only in this one
> place? This looks weird to me.

yes, i only want to force it here, because it's the only place where collation 
matters in the func currently.

> Much like fixing tiny bug and trying to
> avoid checking whether anything else is affected.

yeah, because forcing specific behavior for an entire function is always the 
correct answer.  it's like telling people to export LC_ALL=C in make.conf so 
they never hit locale related problems.

feel free to read the whole func yourself if you think there are other places 
where this matters.
-mike

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