Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:53126
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: error (pb1.pair.com: domain schlueters.de from 217.114.211.66 cause and error)
To: Lars Strojny <lars@strojny.net>
Cc: internals@lists.php.net
In-Reply-To: <CA11DDD5.99DF1%lars@strojny.net>
References: <CA11DDD5.99DF1%lars@strojny.net>
Content-Type: text/plain; charset="UTF-8"
Date: Tue, 07 Jun 2011 12:40:13 +0200
Message-ID: <1307443213.1894.848.camel@guybrush>
Mime-Version: 1.0
Content-Transfer-Encoding: 8bit
Subject: Re: [PHP-DEV] Implementation help needed: Currying RFC
From: johannes@schlueters.de (Johannes =?ISO-8859-1?Q?Schl=FCter?=)

On Mon, 2011-06-06 at 01:28 +0200, Lars Strojny wrote:
> I¹ve finally found some time to put together a first draft of an RFC for
> currying (https://wiki.php.net/rfc/currying). This is basically meant as a
> starting point to find a clean and concise syntax for PHP. So, if you
> kinda like what you¹ve read or you think it¹s crazy or anything in
> between, drop me a message.

I wonder how your proposal would work with a variable number of
arguments.

Taking a piece out of your RFC:
    $apos = curry strpos(..., 'a'));
Would the parameter always be appended? So what would happen here:

    $apos();   // runtime error wrong param count?
    $apos("bar"); // fine
    $apos("bar", "foo"); // 'a' casted to long, used as offset?
    $apos("bar", "foo", 0); // run-time error wrong param count?

I feel that this won't fit easily in the language, while the feature
itself can be nice with all these callback things. I also don't know if
it can be implemented in an efficient way. A simple way to implement is
to create a closure. (which has performance impacts and misleading error
messages in the cases shown above)

I also think that

    Keyword curry should have an alias schoenfinkel

should not be the case. It is nice to remember some people and such but
I think this alias is just one more thing to know when reading code but
serves no real purpose. I know the concept mostly as currying, Scala for
instance seems to always reference it as currying.

johannes