At 7:42 AM +0000 12/22/05, Luke Palmer wrote:
Recently, I believe we decided that {} should, as a special case, be
an empty hash rather than a do-nothing code, because that's more
common.
However, what do we do about:
while $x-- && some_condition($x) {}
Here, while is being passed a hash, not a do-nothing code. Should we
force people to write:
while $x-- && some_condition($x) {;}
Or should we make a counter-special case of some sort? Or should we
take out the {} special case altogether and force people to write
hash()?
Luke
While I'm not strongly on one side or another ...
I'm inclined to make "{}" mean empty hash and {;} mean empty sub, all
the time, since given common usage patterns, that would be a lot
better huffman coded.
On a separate but related matter, I'm in the position of wanting to
do something unusual, which is create a data file format whose
content is executable perl code that defines a data structure, a hash
of whatever.
Kind of like how XML works except that Perl can natively parse it.
Moreover, I'm wanting this format to parse natively with both Perl 5
and Perl 6.
All it would contain is anonymous hashes, arrays, scalars, with a
single hash being the common root container.
Now, aside from the empty hash thing, I believe that the Perl 5 and
Perl 6 syntax is identical. To get around the empty hash thing, I'm
simply not storing empty hashes at all (they don't actually carry
information).
However, if the {} would mean empty hash in both languages, I could
code more tersely and just output all hashes regardless of whether
they're empty or not.
Of course, don't let this esoteric situation sway you, and I do have
a workaround, but suffice it to say there's still the huffman
advantage of {}.
As well as the advantage of fewer changes of Perl 5 to Perl 6 porters.
-- Darren Duncan
