[#66126] Creation/Conversion methods/functions table for Ruby types — SASADA Koichi <ko1@...>
Hi,
5 messages
2014/11/07
[#66248] [ruby-trunk - Feature #10423] [PATCH] opt_str_lit*: avoid literal string allocations — normalperson@...
Issue #10423 has been updated by Eric Wong.
3 messages
2014/11/13
[#66595] [ruby-trunk - Bug #10557] [Open] Block not given when the argument is a string — bartosz@...
Issue #10557 has been reported by Bartosz Kopinski.
3 messages
2014/11/30
[ruby-core:66335] [ruby-trunk - Feature #10498] Make `loop` yield a counter
From:
shortcutter@...
Date:
2014-11-17 20:44:23 UTC
List:
ruby-core #66335
Issue #10498 has been updated by Robert Klemme.
I am actually against this feature. Reason: an infinite loop does not need a counter. We incur the cost of counting (especially when the figure leaves Fixnum space) on _all_ infinite loops. For loops that have a fixed condition on the number (some have been shown with step take or other) that condition can be used upfront with a range or #step.
One can create a counting infinite loop like this:
~~~
x = Enumerator::Generator.new {|y| i = 0; loop {y << i; i += 1}}
~~~
or even
~~~
x = Enumerator::Generator.new {|y| i = -1; loop {y << (i += 1)}}
~~~
If needed that can be made a constant somewhere, e.g. in Enumerator.
----------------------------------------
Feature #10498: Make `loop` yield a counter
https://bugs.ruby-lang.org/issues/10498#change-49991
* Author: Franck Verrot
* Status: Open
* Priority: Normal
* Assignee: ruby-core
* Category: core
* Target version: current: 2.2.0
----------------------------------------
# Problem
Teaching Ruby, we always end up with that type of construct
```ruby
i = 0
loop do
i += 1
# do something with i....
raise StopIteration if i ...
end
```
# Solution
What I propose with this patch is making `loop` yield the iteration count:
```ruby
loop do |i|
# do something with i....
raise StopIteration if i ...
end
```
`i` starts at 0 and stops at `FIXNUM_MAX` (there's no `Float::Infinity` equivalent for integers).
# Alternate solution
`Integer#times` could work if we had an `<Integer's infinity>` object, so we would just do `<Integer's Infinity>.times { |i| ... }`.
Also, this is the very first patch I submit to Ruby, I might have done something horrible, feel free to tell me :-)
---Files--------------------------------
0001-vm_eval.c-loop-now-yields-a-incremented-counter.patch (1.74 KB)
0001-vm_eval.c-loop-now-yields-a-incremented-counter.patch (1.86 KB)
--
https://bugs.ruby-lang.org/