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Date: Wed, 11 May 2016 18:19:55 -0500
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Subject: Re: [PHP-DEV] [RFC] Pipe Operator
From: larry@garfieldtech.com (Larry Garfield)

On Mon, May 9, 2016, at 10:21 PM, Stanislav Malyshev wrote:
> Hi!
> 
> > |> seems like a common symbol to use, but it admittedly does look a
> 
> So, usage in one semi-obscure language (F#) and one completely obscure
> one (Elixir) - Clojure doesn't use |> - and one proposal for Javascript
> now qualifies for "common". And that counting the fact that neither of
> them actually uses the worst part of proposed syntax - magic variable $$.
> -- 
> Stas Malyshev
> smalyshev@gmail.com

If the issue is $$ feels too Perl like, what is the alternative?  Is
there another way to chain methods cleanly?

In a sense, what we're really talking about here is continuations. 
Continuations (over-simplified) are a clean way of setting up "run this
function, pass its result to this function, pass its result to this
function, etc."  That makes composition really easy.  |> is essentially
a continuation syntax.  The $$ is to work around the fact that PHP
function can have an arbitrary number of parameters, whereas
continuations work best with single-parameter functions.

Of course, with currying any multi-parameter function can be reduced to
a series of single parameter functions.  So what if we were to limit the
concurrency syntax to single-parameter functions?  And if you want to
reduce a multi-parameter function to a single parameter function, yay
closures.

Would that limitation help or hinder?

Either way, I firmly believe that more functional-friendly capabilities
like continuations, promises, etc. are a direction that PHP needs to
move, and syntax in that direction is valuable.