Make false, null and true to be recognized as constants in PHP

[ghost]

Resolves #1693.

[RunDevelopment]

I get that null and booleans should have the class constant but why also predefined-constant?
This class is not supported by Prism's themes and it does not capture other predefined constants. (I don't want to suggest that we should try to match all predefined constants.)

Also, is the null class really necessary?

[RunDevelopment]

Why don't you just overwrite clike's boolean in extend?

[ghost]

Why don't you just overwrite clike's boolean in extend?

I think the boolean regex should be executed before class-name, because a boolean can’t be a class/trait name (see the table in #1693).

Currently, Prism converts

<?php
class true
{
}

to

<span class="token keyword">class</span> <span class="token class-name">true</span>
<span class="token punctuation">{</span>
<span class="token punctuation">}</span>

Overwriting boolean from clike doesn’t fix it.

Using insertBefore() I get

<span class="token keyword">class</span> <span class="token boolean constant predefined-constant">true</span>
<span class="token punctuation">{</span>
<span class="token punctuation">}</span>

Anyway, I can make changes if this behaviour is intentional. Maybe I overdid this.

[ghost]

Same with null.

[mAAdhaTTah]

I will say, conceptually, Prism is not a strict linter. My understanding is class true in PHP would be a syntax error, so I'd be more concerned here w/ reducing the amount of code we ship than getting the highlighting exactly right.

[ghost]

Yes, I can keep it simple :)

Prism.languages.php = Prism.languages.extend('clike', {
	// ...
	'constant': [
		{
			pattern: /\b[A-Z_][A-Z0-9_]*\b/
		},
		{
			pattern: /\b(?:null)\b/i
		}
	],
	'boolean': {
		pattern: /\b(?:false|true)\b/i,
		alias: 'constant'
	},
	// ...
});

false and true get token boolean constant.

null loses keyword and gets token constant.

Is it better?

[ghost]

class true in PHP would be a syntax error

Yes.

I will say, conceptually, Prism is not a strict linter.

Right. I definitely tried to make it lint. I’ll fix that.

[RunDevelopment]

Yes, that definitely better.

Just two small nits:

1. Please don't write { pattern: /.../ }. Just use the regex directly.
2. Please position boolean before constant. constant after boolean creates the false impression that boolean is matched after constant.

[RunDevelopment]

Thank you for contributing!

[ghost]

Great! Thank you very much for your help!