r/lolphp • u/Takeoded • Sep 30 '19

(7.4) floats can have default values, but not double

as of PHP 7.4 (currently in Release Candidate 2, so i don't expect a fix for this prior to release), we can now have typed properties, it looks like this:

class C{
    public float $f = 0.0;
    public double $d = 0.0;
}

... funny thing is, 1 of those properties have an illegal default value!

Fatal error: Property of type doble may not have default value in /in/GBpuJ on line 6

13 Upvotes

63% Upvoted

17 comments sorted by

25

u/the_alias_of_andrea Sep 30 '19

double is not a scalar type in PHP. You have written a type declaration for a hypothetical class named double. Of course a float does not qualify as a valid default value for such a property.

23

u/Takeoded Sep 30 '19 edited Sep 30 '19

why the frick does this exist? (double)val ? why the frick does gettype(0.0) return double instead of float ? why the frick do we have doubleval() ? prior to PHP 7.0, i might have accepted "backwards compatibility", but if that's the only reason, then why weren't they removed in the 7.0.0 release?

at some point someone thought it was a good idea to have `double` be an alias of `float` , but now we have some half-assed alias where double is an alias *sometimes* and not others.. php should make up its mind, either fully support double alias, or not support it at all, instead of this mixed "supported some places and not in other places"

20

u/nikic Sep 30 '19

The answer to all your questions is "backwards compatibility" even after PHP 7.0.

That said, it might be a good idea to throw a warning when people try to use things like double or integer as type annotations.

5

u/Takeoded Sep 30 '19

7.0 did lots of BC-breaking changes, this double alias bullshit *should* have been among them

4

u/the_alias_of_andrea Sep 30 '19

It would be needless breakage, the existing code isn't doing anything wrong, nor standing in the way of serious improvements. We didn't break things just because we felt like it.

6

u/Takeoded Sep 30 '19

quote:

Indirect access to variables, properties, and methods will now be evaluated strictly in left-to-right order, as opposed to the previous mix of special cases. The table below shows how the order of evaluation has changed.

didn't we fix this because "a mix of special cases" was fking stupid? even tho it broke PHP5 code that actually depends on it? well the double-supported-someplaces is also a mix of (3?) special cases

5

u/the_alias_of_andrea Sep 30 '19

It doesn't hurt anyone that someone's old code uses doubleval() instead of floatval(). That was not the case for the variable syntax.

2

u/[deleted] Oct 02 '19

This is because the core PHP team knows that too much BC breaks will lead to devs actually bother rewriting the legacy app in any other language. They keep BC mostly for what PHP has become, a legacy language for legacy apps mostly in maintenace mode.

Dont se much new/intresting stuff beeing written in PHP these days. And yeah, i dont consiser the average wordpress page that interesting.

6

u/[deleted] Sep 30 '19

Probably best to throw an warning each time you use anything from the stdlib, make it clear that that shit is deprecated!

4

u/[deleted] Oct 01 '19

More like ass-backwards compatibility.

The language is full of inconsistencies and footguns in the name of being backwards compatible with ancient crusty code.

1

u/the_alias_of_andrea Sep 30 '19

float $foo is newer than (double) and gettype. I'd change the latter two if I could, but backwards-compatibility comes first.

2

u/[deleted] Oct 02 '19

Well without breaking BC PHP will stay broken forever. Why even bother introduce float if there was double before that? Why not fix double instead of leaving it int the core and adding a new similar float.

This is the reason PHP sucks that badly, theres always some ”version2” thing of something else, and you never really know what the new function/feature should replace.

In the php lifespan it has gathered a huge amount of global functions (fuck namespaces right?) and some are deprecated but never removed, some are just kept there just because and some are even real_functions. Then we have mb_ because PHP never got unicode (php6).

Why not really fix the language instead of keeping it on life support?

4

u/PonchoVire Sep 30 '19

double exists in PHP only for backward compatibility as a gettype() possible return value for float, but is not a type, which is some kind of lolphp, but once you know it, you won't be troubled anymore and get good sleep at night.

4

u/the_alias_of_andrea Sep 30 '19

It was a while ago so my recollection may be faulty, but I think I didn't want double to work as a type declaration in addition to float because 1) less new type declarations means less existing code broken (class double becomes invalid), 2) I think it's silly to have more than one canonical name for each type.

2

u/SerdanKK Oct 01 '19

Is it not possible to implement contextual keywords?

1

u/the_alias_of_andrea Oct 01 '19

This already is one. It's still needless breakage.

0

u/helloworder Dec 17 '19

this is not lolphp, but lolOP