On 05/14/2016 07:42 PM, François Laupretre wrote:
Le 13/05/2016 à 20:16, Sara Golemon a écrit :
for a potential solution to such a long-time issue as argument ordering
sadness, IMHO, it's worth the pain. I am currently doing it and I'll
send
you the list when it is ready.
Awesome. Even if not used in this feature, it could potentially be
useful elsewhere. I hope you put it in a public gist or similar for
posterity.
After a quick check of every functions available in the PHP distrib,
only 55 functions should insert the lhs in a position different from 0
(first argument). From these 55 functions, 4 must not be used in a
pipeline and, for the remaining 51, the lhs must be inserted as 2nd,
3rd, or 4th argument. The list and positions to use are available at :
http://tekwire.net/joomla/projects/ideas/pipe-operator
So, the logic would be :
- if the function accepts 0 mandatory argument, it cannot be used in a
pipeline,
- if the function is in the table referenced above, use the position
from the table,
- else, insert the lhs as 1st arg.
For internal functions, we can easily use some unused part of the 1st
arginfo element to store the position. The default will remain 0,
which doesn't require any change in current arginfo declarations.
We'll just have to define a new ZEND_BEGIN_ARG_INFO_xxx macro with an
explicit position. This macro will be used for the 55 functions
requiring a specific non-default position. -1 will be used to mark a
function as unusable in a pipeline.
Once again, I think that argument ordering is a very important issue
and, here, we have an unique occasion to solve it for a rather
moderate price, since every functions have been audited.
Another issue is caused by the sort functions returning the sorted
array by reference. The problem is the same with or without '$$'. In
practice, these functions cannot be used in a pipeline. So, either we
change their behavior to be different when used in a pipeline, which
is weird but allows an intuitive '|> sort() |>' notation, or we need
to define a new set of functions returning sorted arrays. None of
these is perfect but we'll have to propose a solution, as sorting is
essential when driving an array through a pipeline.
Regards
François
This still sounds awfully complicated to me. I would far, far prefer
the $$ syntax to special casing function aliases just to dance around
it. If we had a short-function syntax then requiring a piped function
to have only a single argument would be both reasonable and
typing-efficient. Baring that, the $$ syntax seems far nicer than
alternate versions of functions with implicit arguments but only in
certain situations.
Side note: Please, people, use the Reply-List function in your email
clients. I've gotten double-copies of everything in this thread since my
last email. :-/
Also to Stas: Yes, I meant "continuation" earlier, not "concurrency";
brain fart on my part, as the latter clearly makes no sense at all in
context. In particular, I'm referring to Continuation-passing style:
https://en.wikipedia.org/wiki/Continuation-passing_style
Again, I think there's a lot of potential to this syntax, especially if
we can find a way to make it forward-compatible with
promises/async-await, or whatever we end up with in the async world.
(Which... I suppose makes continuations a concurrency syntax after all,
which may be why I brain farted on the C word I meant to type.)
--Larry Garfield
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