Signatures and option specs [was: Open and pipe]
On Mon, May 02, 2005 at 09:52:35PM +0200, Juerd wrote: I already suggested a syntax like '+$write|w' for having multiple ways to say the same thing. I don't like an explicit :mode. Let Perl figure that out based on passed named arguments. I'd like to see this specced. What you're suggesting is that sub signatures have something as powerful as a good getopt library; things that spring to mind at this prospect are: * canonical representations (eg, :w in your example should probably set $write) * mutually exclusive options (for open modes, :write should exclude :append) * computed options (if by let Perl figure that out $mode you didn't mean let perl's open figure it out with explicit code). How would you suggest formalizing these? (By the way, we need a spec for perl's command line, too. So far we've been emulating perl5's in an ad-hoc manner.) -- Gaal Yahas [EMAIL PROTECTED] http://gaal.livejournal.com/
Re: Signatures and option specs [was: Open and pipe]
Gaal Yahas skribis 2005-05-04 13:48 (+0300):
* canonical representations (eg, :w in your example should probably set
$write)
Or, possibly, $w := $write.
* mutually exclusive options (for open modes, :write should exclude
:append)
I don't really care if this goes in the signature. Runtime checking is
good enough for this.
sub foo (+$write, +$append) {
fail ... if $write and $append;
...
}
Although I don't think this particular check is needed at all, as append
isn't quite opening the file read-only. Just ignore that :write was also
given.
* computed options (if by let Perl figure that out $mode you didn't mean
let perl's open figure it out with explicit code).
I did mean let open figure it out. That is, let open decide based on
the named arguments it gets how to open something. Let *it* find a way
to specify 'a+' and stuff like that, so we can write it readably.
Juerd
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