In perl.git, the branch smueller/hash_vtable_make_hash has been created
<http://perl5.git.perl.org/perl.git/commitdiff/c852987cc09f01373754d0344a2b5f5e979471f5?hp=0000000000000000000000000000000000000000>
at c852987cc09f01373754d0344a2b5f5e979471f5 (commit)
- Log -----------------------------------------------------------------
commit c852987cc09f01373754d0344a2b5f5e979471f5
Author: Steffen Mueller <smuel...@cpan.org>
Date: Wed Feb 1 19:59:06 2017 +0100
Hash vtables: Fall through to runtime evaluation if vtbl not found
If the vtable for a given constant string isn't found, we simply do the
evaluation (again) at run-time. Until then, somebody may have added the
right vtable to the registry.
This means that compile/run-time behavior change that the previous
commit introduced ("foo" vs. $foo as first argument to make_hash) is
MOSTLY dealt with. The only remaining exception is that if somebody
overwrites a vtable entry in the global registry. But that's so naughty
that I think it's okay just to document not to do that. (You need to
really know what you're doing if you'd be writing your own hash tables
for perl anyway.)
This does have one ancillary downside: We don't get compile time
exceptions on invalid vtable names any more and downgrade them to
runtime exceptions. That seems worth it, considering it fixes an ugly
wart.
M ext/Hash-Pluggable/Pluggable.xs
commit d57c06546eee71e4f77813c2a725505a9b4d0e10
Author: Steffen Mueller <smuel...@cpan.org>
Date: Wed Feb 1 19:56:08 2017 +0100
Hash vtables: Evaluate constant strings for vtbls at compile time
With this change, "make_hash("some_vtable_name", ...)" will be resolved
to a vtbl pointer (corresponding to 'some_vtable_name') at compile time.
This speeds up make_hash by a factor of several (roughly 3x) in such
cases.
M ext/Hash-Pluggable/Pluggable.xs
commit 3d6235022779c1902a9a31c28d8c8386334678bf
Author: Steffen Mueller <smuel...@cpan.org>
Date: Mon Jan 30 20:09:22 2017 +0100
Hash vtables: Add std mock vtable to registry
M ext/Hash-Pluggable/Pluggable.xs
M ext/Hash-Pluggable/lib/Hash/Pluggable.pm
commit f527f1439509dcd987de8ee60fb7a37717659cd0
Author: Steffen Mueller <smuel...@cpan.org>
Date: Mon Jan 30 12:46:26 2017 +0100
Hash vtables: Extend Hash::Pluggable hobo-docs
M ext/Hash-Pluggable/Pluggable.xs
commit 055b7de0ecdc55fcae2cc78bc1ff09db61af65fc
Author: Steffen Mueller <smuel...@cpan.org>
Date: Mon Jan 30 12:40:11 2017 +0100
Hash vtables: Remove debugging code
M ext/Hash-Pluggable/Pluggable.xs
commit 7f9ca9a2666b987be2c318d54f06d44100d78571
Author: Steffen Mueller <smuel...@cpan.org>
Date: Mon Jan 30 12:39:42 2017 +0100
Hash vtables: Hobo-documentation in the sources
At least explain what this does in a comment for future me. :)
M ext/Hash-Pluggable/Pluggable.xs
commit f6cbeef884dc98992f10042341b90f6b0af888bc
Author: Steffen Mueller <smuel...@cpan.org>
Date: Mon Jan 30 12:38:55 2017 +0100
Hash vtables: croak on invalid vtable names
M ext/Hash-Pluggable/Pluggable.xs
commit 5a1c63d26984565380045cd10ccdf79cb9aefc97
Author: Steffen Mueller <smuel...@cpan.org>
Date: Mon Jan 30 12:38:07 2017 +0100
Hash vtables: Eschew mortal copy
I don't think it's necessary here as we're not looking to co-opt it into
a hash key.
M ext/Hash-Pluggable/Pluggable.xs
commit b03980364cfd4b15e7567bd41f84fd415b7479b8
Author: Steffen Mueller <smuel...@cpan.org>
Date: Mon Jan 30 09:22:05 2017 +0100
Hash vtables: First stab at implementing an interface
This introduces a new module, Hash::Pluggable. It provides a new keyword
"make_hash" (better naming suggestions welcome) which acts just like a
normal anon hash constructor, {}, in that is creates and returns a hash
ref. It's implemented as a custom OP very similar to the actual
OP_ANONHASH.
It does, however, use its first argument to determine its hash type.
As of this commit, it will use it to look up the vtable to use in a
global registry at run time.
What's missing:
- A way to add vtables to the registry.
- Erroring out if it's an unknown vtable.
- Moving the lookup to compile time... but...
- So it should be possible to do this lookup at compile time if it's
a static string. This is still TODO.
- This does unfortunately pose a problem in that it would make
behavior inconsistent. With that, if it's a static string, the
vtable would be looked up at compile time. If it's an expression,
the vtable would be looked up at run time. I'm not sure how big a
deal this is necessarily (seems less bad than trying to randomly
evaluate some expression at compile time!), but it means that the
state of the vtable registry could change inbetween.
M MANIFEST
M Makefile.SH
A ext/Hash-Pluggable/Pluggable.xs
A ext/Hash-Pluggable/lib/Hash/Pluggable.pm
A ext/Hash-Pluggable/t/01basic.t
-----------------------------------------------------------------------
--
Perl5 Master Repository
