Issue #10498 has been updated by Joffrey Jaffeux.


Franck Verrot wrote:
> I might have overlooked them, but I can't find any reference to any other`*_with_index` method than `each_with_index`. Are they in Ruby core or in an external gem?

`each_with_index` does exist, but concerning `map`, Martin was probably talking about `map.with_index` as defined in http://ruby-doc.org/core-2.1.5/Enumerator.html#method-i-with_index

Using `loop.with_index {|i| puts i}` will currently yield nil.

----------------------------------------
Feature #10498: Make `loop` yield a counter
https://bugs.ruby-lang.org/issues/10498#change-49963

* 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)


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