Re: Scalar type hinting

From: Date: Mon, 27 Feb 2012 15:47:02 +0000
Subject: Re: Scalar type hinting
References: 1 2 3 4  Groups: php.internals 
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2012/2/27 Johannes Schlüter <[email protected]>

> Hi,
>
> PHP is no strickt-typed language. Changing this is a massive change, if
> you want to go there: There are plenty of other languages.
>
> If you want this to be an optional feature:
> a) It's not optional (one has to maintain code written by others, uses
> libraries, frameworks, ...)
> b) It causes a hell lot of trouble with copy-on-write. going from
> fixed-typed to non-fixed-typed variables (in a funciton call or
> assignment or such) will always have to cause a copy. This will hurt the
> performance in hardly predictable ways.
>
> johannes
>

Big +1 from me. Thanks for the post Johannes!

It makes sense to have a type hint for the different type of data
structures.
1) array
2) object ( class name for OOP ).

The scalar values (int, string, double) are type-less, flexible and should
remain that way. If you want strict typehinting then move to another
language.


>
> On Mon, 2012-02-27 at 09:29 -0500, Michael Morris wrote:
> > What I've wanted for awhile, but don't know what the implementation
> > problems would be, is to allow for two new variable types to solve
> > this problem - Strict and tolerant variables.  Both of these must be
> > declared formally (otherwise PHP assumes scalar) and the datatype must
> > be included. The syntax
> >
> > // A tolerant variable.
> > integer $a = 3;
> >
> > // A strict variable
> > strict integer $b = 2;
> >
> > Tolerant variables silently cast values to their declared datatype.
> > Maybe they should raise E_NOTICE?
> > Strict variables refuse to be assigned a value with an incorrect
> > datatype.  Raise E_WARNING?
> >
> > A strict function would have the current behavior of kicking a warning
> > when the type hinting fails.  Otherwise, functions should be tolerant
> > -
> >
> > function foo ( integer $a, string $b, $c ) {}
> >
> > strict function foo ( integer $a, $string $b, $c ) {}
> >
> > A function parameter without a datatype would be ignored.
> >
> > This does open the door to function overloading, but the engine
> > problems of this are well documented and have been discussed.  Still,
> > I don't think it's a bad thing to have a syntax that allows for method
> > overloading in the future.
> >
> > On Sun, Feb 26, 2012 at 10:52 PM, Kris Craig <[email protected]>
> wrote:
> > > I'll try to find some time tonight to create that for ya.
> > >
> > > Once this discussion comes together a little bit more and we have at
> least
> > > a vague-ish idea what direction we're moving in, I'll also go ahead and
> > > create an RFC as well so we have a conceptual product to build on.
> > >
> > > --Kris
> > >
> > >
> > > On Sun, Feb 26, 2012 at 6:27 PM, Samuel Deal <[email protected]>
> wrote:
> > >
> > >> Hi,
> > >>
> > >> I create a new thread to discuss about Scalar type hinting.
> > >>
> > >> Following the John Crenshaw proposed terminology:
> > >> > - "Strict Typing" means the super strict old C style typing that
> > >> > has
> > >> been proven to be ridiculous in this environment because of the
> obvious
> > >> problems inherent in the fact that almost every input is a string.
> > >> > - "Weak Typing" means types in the same sense that the PHP
> documentation
> > >> uses types (for example, the docs indicate substr(string, integer),
> and
> > >> substr(12345, "2") == "345".)
> > >> > - "No Scalar Typing" should be used to indicate the current system
> > >> (where there is no provision for hinting at scalar types.)
> > >>
> > >> Previous weak typing proposal could be found here :
> > >> https://wiki.php.net/rfc/typechecking
> > >>
> > >> I have no rights to edit the wiki and make a summary of previous
> > >> arguments, so if someone could create it...
> > >>
> > >>
> > >> --
> > >> Samuel DEAL
> > >> [email protected]
> > >>
> > >>
> >
>
>
>
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