Re: PATCH: Add g:: parameter expansion flag

[Mikael Magnusson <mikachu@xxxxxxxxx>]

On 13 May 2011 10:54, Peter Stephenson <Peter.Stephenson@xxxxxxx> wrote:
> On Thu, 12 May 2011 21:41:36 +0200
> Mikael Magnusson <mikachu@xxxxxxxxx> wrote:
>> On 12 May 2011 17:49, Mikael Magnusson <mikachu@xxxxxxxxx> wrote:
>> > Okay, how's this? I swapped the order so g happens first, and
>> > changed the docs as discussed.
>>
>> Just as I was thinking about committing it, I found a bug. I have to
>> metafy the result of getkeystring().
>> % print -Rn ${(g:o:):-'\201\227\343\201\257'}|wc -c
>> zsh: command not found: は
>> 1
>>
>> Not exactly the intended result :).
>>
>> So I am pretty sure I want to use META_HREALLOC, is that correct? Ie
>>           if (!copied)
>>               val = dupstring(val), copied = 1;
>>           val = getkeystring(val, &len, getkeys, NULL);
>>             val = metafy(val, len, META_HREALLOC);
>> (and same for the isarr case)
>>
>
> That would do, as it's what untok_and_escape() does, although
> META_HEAPDUP would probably be OK at this point.  Reallocating what's
> on the heap is a slightly strange thing to do, since the point of the
> heap is to provide quick storage without the need to micromanage it;

In that case, isn't USEHEAP better? It'll allocate on the heap if
there's anything to escape and otherwise do it in-place. Which is what
I thought HREALLOC would do, but I guess that one would do more stuff
to try and just grow. Won't it always succeed though, since the to-be
reallocated value was just allocated on the line before? (At least
when the heap isn't full).

> it
> tends to be done when there's a long string on the heap that it would
> be inefficient to keep duplicating, which isn't the case here.  If the
> original heap chunk is surrounded by other allocations it has to
> duplicate anyway, since the heap doesn't let you reuse memory (until
> the whole heap is popped); you can't tell just be looking at the call
> whether this will be the case.

Why can't the string be long? Not that I think anyone would really
notice anyway :).

-- 
Mikael Magnusson