From: Alexey@..., Muranov@...
Date: 2014-01-13T09:14:21+00:00
Subject: [ruby-core:59738] [CommonRuby - Feature #9401] Yet another syntax for literal anonymous functions (lambdas)

Issue #9401 has been updated by Alexey Muranov.


Nobuyoshi Nakada wrote:
> What about `(^x) {x*x}`?

I think, my initial attempt was closer to lambda calculus notation `(��x(x*x))`, to its modern variant `(x|->x*x)`, to Haskell `(\x -> x*x )`, to Ruby block syntax `{|x| x*x }`, and to Ruby hash syntax `{ 2 => 2*2 }`.

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Feature #9401: Yet another syntax for literal anonymous functions (lambdas)
https://bugs.ruby-lang.org/issues/9401#change-44259

* Author: Alexey Muranov
* Status: Open
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
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Please do not be angry at me and just close this proposal if it does not look interesting.  It comes from my aesthetic dissatisfaction with the `->(x){ ... }` literal anonymous function notation and from my amateurish interest in lambda calculus.

Here is a yet another syntax for literal anonymous functions (lambdas) that i propose:

    f = {\ x => x*x }
    f[1] # => 1
    f[2] # => 4

It looks a bit like a hash on purpose: i think that a hash is a "function in extension" and a lambda is a "function in intension" (see, for example, in [these notes](http://www.classes.cs.uchicago.edu/archive/2004/spring/15300-1/docs/lambda-intro.pdf)).  The backslash stands for "lambda", like in Haskell.



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