[#79914] [Ruby trunk Bug#13282] opt_str_freeze does not always dedupe — normalperson@...
Issue #13282 has been reported by Eric Wong.
4 messages
2017/03/05
[#80140] [Ruby trunk Feature#13295] [PATCH] compile.c: apply opt_str_freeze to String#-@ (uminus) — shyouhei@...
Issue #13295 has been updated by shyouhei (Shyouhei Urabe).
5 messages
2017/03/13
[#80362] Re: [Ruby trunk Feature#13295] [PATCH] compile.c: apply opt_str_freeze to String#-@ (uminus)
— Eric Wong <normalperson@...>
2017/03/26
shyouhei@ruby-lang.org wrote:
[#80368] Re: [Ruby trunk Feature#13295] [PATCH] compile.c: apply opt_str_freeze to String#-@ (uminus)
— SASADA Koichi <ko1@...>
2017/03/27
On 2017/03/26 15:16, Eric Wong wrote:
[#80205] Re: [ruby-cvs:65166] duerst:r58000 (trunk): clarifiy 'codepoint' in documentation of String#each_codepoint — Eric Wong <normalperson@...>
duerst@ruby-lang.org wrote:
4 messages
2017/03/17
[#80213] Re: [ruby-cvs:65166] duerst:r58000 (trunk): clarifiy 'codepoint' in documentation of String#each_codepoint
— Martin J. Dürst <duerst@...>
2017/03/17
Hello Eric,
[#80290] [Ruby trunk Feature#13355] [PATCH] compile.c: optimize literal String range in case/when dispatch — normalperson@...
Issue #13355 has been reported by normalperson (Eric Wong).
4 messages
2017/03/23
[#80410] Re: [Ruby trunk Feature#13355] [PATCH] compile.c: optimize literal String range in case/when dispatch
— Eric Wong <normalperson@...>
2017/03/27
normalperson@yhbt.net wrote:
[#80415] [Ruby trunk Feature#12589] VM performance improvement proposal — vmakarov@...
Issue #12589 has been updated by vmakarov (Vladimir Makarov).
5 messages
2017/03/28
[#80488] [Ruby trunk Feature#12589] VM performance improvement proposal — vmakarov@...
Issue #12589 has been updated by vmakarov (Vladimir Makarov).
4 messages
2017/03/29
[ruby-core:79868] [Ruby trunk Feature#12901] Anonymous functions without scope lookup overhead
From:
eregontp@...
Date:
2017-03-02 10:44:24 UTC
List:
ruby-core #79868
Issue #12901 has been updated by Benoit Daloze.
To come back to the main topic of this issue,
I think having some syntax support for a non-capturing lambda
can be a useful feature in Ruby, but should not be for performance reasons.
It should be a design tool.
If a lambda/proc does not use captured variables, there is no reason
for it to lookup parent scopes. So there should not be any scope lookup overhead
if a lambda/proc does not capture variables.
What is the source of the overhead for calling lambdas on MRI?
Is it restoring the implicit state (self, cref, a pointer to the parent frame
in case #binding is called, etc) that must be restored? Some extra checks?
Kernel#binding applies to all kinds of lambdas/procs and
that affects how frames can be represented but it is mostly orthogonal
to this issue (methods also have to care about Kernel#binding).
----------------------------------------
Feature #12901: Anonymous functions without scope lookup overhead
https://bugs.ruby-lang.org/issues/12901#change-63301
* Author: Richard Schneeman
* Status: Open
* Priority: Normal
* Assignee:
* Target version:
----------------------------------------
Right now if you are writing performance sensitive code you can get a performance bump by not using anonymous functions (procs, lambdas, blocks) due to the scope lookup overhead.
https://twitter.com/apotonick/status/791167782532493312?lang=en
I would like to be able to create an anonymous function and specify I don't need it to perform the lookup when called.
I am thinking that this code:
~~~
Proc.new(scope: false) {|var| puts var }
~~~
Would be the equivalent of
~~~
def anon(var)
puts var
end
~~~
If you call it while trying to access something from outside of the scope it would error
~~~
var = "hello"
Proc.new(scope: false) { puts var }.call
# => NameError: undefined local variable or method `var' for main:Object
~~~
An example of a case where this could be used is found in https://github.com/rails/sprockets/pull/417. In this case we are getting rid of anonymous functions in favor of a method created with refinements. This solution works but it was not an obvious optimization. It would be convenient to have a syntax for defining anonymous functions that do not need access to caller scope.
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