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To: "G. P. B." <george.banyard@gmail.com>, PHP internals
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Thread-Topic: [PHP-DEV] Re: [RFC] Numeric Literal Separator
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Date: Wed, 29 May 2019 15:48:14 +0000
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Subject: Re: [PHP-DEV] Re: [RFC] Numeric Literal Separator
From: theodorejb@outlook.com (Theodore Brown)

On Wed, May 29, 2019 at 6:34 AM G. P. B. <george.banyard@gmail.com> wrote:=
=0A=
=0A=
> I share the same concerns as Rowan Collins=0A=
=0A=
From my reading of Rowan's email, he was making a general point that=0A=
new features can have a cost of added complexity for users. He then=0A=
clarified "I don't personally think that applies here".=0A=
=0A=
> I'm really not a fan of the RFC in general. Also I think those kind=0A=
> of magic numbers should be constants with meaningful names, and it=0A=
> that case you could just compute them by adding powers of ten.=0A=
> E.g. DISCOUNT_IN_CENTS =3D 1 * 10^5 + 3 * 10^4 + 5 * 10^3;=0A=
=0A=
Actually I think this example highlights why numeric literal=0A=
separators can be very helpful for improving readability and=0A=
preventing mistakes. First, which of these is faster to read?=0A=
=0A=
```php=0A=
$discount =3D 1 * 10**5 + 3 * 10**4 + 5 * 10**3;=0A=
// or=0A=
$discount =3D 135_00;=0A=
```=0A=
=0A=
Secondly, your example of adding powers of 10 is off by an order=0A=
of magnitude! It's equivalent to $1,350.00, not $135.00, but this=0A=
isn't very obvious when reading the complex expression.=0A=
=0A=
Of course, if you prefer the first approach you can continue using it.=0A=
But personally I find the second approach quicker to read and less=0A=
prone to mistakes.=0A=
=0A=
> Moreover I feel that people may misread numbers like that if people=0A=
> use different groupings. E.g. 1_0000_0000_0000; by skimming rapidly=0A=
> I could think it's a billion(10^6) when in reality it's a trillion=0A=
> (10^9). Even if maybe some countries are moving away from the=0A=
> grouping digits in groups of 4.=0A=
=0A=
Even with the different grouping, it's faster for me to count the=0A=
digits in that number than if it had no separator at all.=0A=
=0A=
> I'll probably vote against it but that's only my opinion.=0A=
=0A=
That's up to you. But even if you don't personally have a need for=0A=
the feature, I think it's worth considering that there are valid use=0A=
cases for it which can help improve code readability and clarify intent.=0A=
=0A=
Best regards,=0A=
Theodore=