elseif vs else if node structure

[pmjones]

This came up in pmjones/php-styler#4 earlier today. PHP-Styler rebuilds this original code using else if:

if ($foo) {
    $foo = 'bar';
} else if ($bar) {
    $foo = 'baz';
}

...to this:

if ($foo) {
    $foo = 'bar';
} else {
    if ($bar) {
        $foo = 'baz';
    }
}

This is because PHP-Parser sees a second If_ as part of the Else_, rather than an Elseif_ that is part of the If_.

How difficult would it be for PHP-Parser to recognize else if as elseif in these conditions? (My guess is that it would involve substantial effort.)

[nikic]

It's not difficult, but then I'll get complaints that the distinction between elseif and else if gets lost ;)

You should be able to easily print these without the extra nesting, like this:

PHP-Parser/lib/PhpParser/PrettyPrinter/Standard.php

Lines 893 to 896 in f5adbb5

	if (\count($node->stmts) === 1 && $node->stmts[0] instanceof Stmt\If_) {
	// Print as "else if" rather than "else { if }"
	return 'else ' . $this->p($node->stmts[0]);
	}

[pmjones]

but then I'll get complaints

Man, I hear you. :-)

You should be able to easily print these

Excellent, I will try that -- thanks!

[pmjones]

Thanks @nikic that did the trick.

[pmjones]

Update: it turns out that was not quite enough. When something like this occurs ...

if (true) {
    if (true) {
        // foo
    } else {
        // bar
    }
} else {
    if (true) {
        // baz
    } else {
        // dib
    }
}

... the final else (with //dib) disappears.

Instead, this mitigation seems to handle it properly (no disappearing else):

if (
    count($node->stmts) === 1
    && $node->stmts[0] instanceof Stmt\If_
    && ! $node->stmts[0]->elseifs
    && ! $node->stmts[0]->else
) {
    // treat as `elseif`
}

Thanks again for the help, and for this project.

[staabm]

Fyi we tried similar things in phpstan, but all suggested solutions until now did not work in all cases.

See phpstan/phpstan#10113

[pmjones]

@staabm Thanks for that -- so, no reliable solution?

[staabm]

Until now, I think no reliable solution, right.

[pmjones]

All right, I may have to go back to pmjones/php-styler#4 and tell him there's nothing to do, other than manually change else if to elseif -- unless someone here can think of other solutions.

[pmjones]

@staabm @herndlm If you recall, can you say what the failure modes were? That is, under what conditions did the else if-to-elseif conversion fail to honor the original logic?