[ruby-core:97952] [Ruby master Feature#16781] alias :fold :reduce

Issue #16781 has been updated by shan (Shannon Skipper).


0x81000000 (/ /) wrote:
> 2. Name "fold" is more common/popular than "reduce" or "inject".

I was surprised to hear this, since I think of "reduce" as most popular. A quick survey of popular languages seems to confirm that "reduce" is most popular, followed by "accumulate."

Reduce:
> 	JavaScript
> 	Python
> 	Java
> 	PHP
> 	Ruby
> 	TypeScript
> 	Swift

Accumulate:
> 	C#
> 	C++

Fold:
> 	*Not found*

You do also see "fold" in functional languages like Clojure, Scala, Elixir, et cetera, where it has a different meaning than "reduce," which is also present. In any case, "inject" has fallen out of favor.

> I have no idea how to properly add "fold" in Ruby's stdlib/corelib.

You could an `rb_define_method(rb_mEnumerable, "fold", enum_inject, -1);` here: https://github.com/ruby/ruby/blob/v2_7_1/enum.c#L4172-L4173

----------------------------------------
Feature #16781: alias :fold :reduce
https://bugs.ruby-lang.org/issues/16781#change-85178

* Author: 0x81000000 (/ /)
* Status: Open
* Priority: Normal
----------------------------------------
1. Method "collect" has short synonym "map", short synonym of "inject" and "reduce" doesn't exist.
2. Name "fold" is more common/popular than "reduce" or "inject".

In my own code I use:
``` 
module Enumerable
    alias :fold :reduce
end
```
I have no idea how to properly add "fold" in Ruby's stdlib/corelib.




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