Re: Directory/file browser as TreeView

[Joe Smith <jes martnet com>]

A. Pagaltzis wrote:
> ... glad I can help. :-)

Thanks for the most clear lesson; very enlightening!

>> What's the "+" for?
>
> To force parsing as a value. Otherwise, Perl thinks these parens
> belong to `sort`, ... That caught me completely by surprise.
> ...
> You can use the unary plus more or less wherever a pair of
> delimiters is ambiguous.

Completely new to me. Of course I'm used to using "0+ list" to force 
scalar context, but I'd never seen the "+(... )" to force sub-expression 
context instead of sub call. Interesting. I would probably have ended up 
with "sort &no_upwards( @content );" as that's more familiar to me and 
it makes it clear that "no_upwards" is a sub, which I never figured out 
until I stepped into it with the debugger! Duh. I'm not used to seeing 
bareword subs I guess.

Certainly the "+(... )" syntax is clear, once you know the secret--not 
unusual for Perl ;-)

> ... However, do this on older
> hardware or with slow filesystems like an NFS mount, and the
> difference will be dramatic. Instead of sitting there like a dead
> duck for 20 seconds or maybe several minutes, the browser will
> remain responsive all along, even if the thing you were looking
> for takes a while to show up.

I can imagine--actually it's cool even on a large local dir to see the 
little triangles wink in as the subs complete.

> ..
> But I was attempting to get the GUI side of things right while
> keeping the code simple enough to be instructional, and I think
> what I got is just barely within that constraint as is.

Agreed--right on the edge. Still, I remember (barely) when I first read 
K&R and most of the examples were complete gibberish at first, but over 
time I learned so much by working through them. Now, more often than 
not, I get frustrated with examples that are so obvious they're hardly 
worth the space to print them.

Thanks again!

<Joe