How to replace all php anonymous functions for fn() using regex on notepad++?

Question

I am trying to update a legacy php code (7.0) for php 7.4 >= and one of the new features that I would like to use the new fn() => syntax, instead of function() use () {}

Unfortunately, I have hundreds of anonymous functions using CakePHP ORM like:

$query->matching('Tags', function ($q) {
    return $q->where(['Tags.name' => 'CakePHP']);
});

Using php 7.4 >= could be:

$query->matching('Tags', fn($q) =>
        $q->where(['Tags.name' => 'CakePHP'])
);

Sometimes using "use":

$query = $articles->find()->matching('Comments.Users', function ($q) use ($username) {
    return $q->where(['username' => $username]);
});

php 7.4 >= (use is not needed):

$query = $articles->find()->matching('Comments.Users', fn ($q) =>
        $q->where(['username' => $username])
    );

Or using two or more params:

$query->where(function (QueryExpression $exp, Query $q) {
    return $exp->eq('published', true);
});

But when you have more than one instruction, fn () cannot be used, for example:

$results->map(function ($row) {
        $row['age'] = $row['birth_date']->diff(new \DateTime)->y;
        return $row;
    });

I would like to use notepad++ regex and replace in all files feature to execute a regex and replace all "possible" functions() for fn().

So, What REGEX could achieve this goal?

Answer 1

Find: function\s*\(([^\(\)]*)\)[^\{]*\{\s*return\s*([^;]*)\s*;\s*\}
Replace: fn\(\1\) => \2