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Date: Tue, 25 Jun 2013 11:01:16 +0100
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Subject: RFC Proposal: New assign value operator
From: tom@scl.co.uk (Tom Oram)

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Hi everyone,

I've got an idea for an RFC proposal and from reading the instructions it
looks like I should run it past you guys first.

I have not made any contributions to PHP before although I have made some
custom modifications in house in the past and while I'm no longer familiar
with the PHP code base I am confident I have the skills to implement this
should it be accepted.

What I want to propose is a new assignment operator which rather than
setting the variable to completely new value it would update the value
while maintaining the type.

The main motivation for this is for easy assignment to value objects aka
assignment operator overloading via a magic method (prehaps called
__assign).

Here is an example ( for now I will use the PASCAL style assignment
operator := as the new operator as it is a know assignment operator and
currently not used in PHP):

// For a class defined like so...
class MoneyValue
{
    protected $amount;

    public function __assign($value)
    {
        $this->amount = $value;
    }
}

// The amount could then be assigned using the new operator like this

$price = new MoneyValue();

$price := 29.99;

While the primary focus would be for assignment operator overloading as I
just displayed in the previous example, for consistency it could be used
with scalar values to preserve type like so:

// $str is now a string

$str = 'Original String';

// Using the new assignment variable would cast the value being assigned to
the variable's type
// (in this case a string). So

$str := 7;

// Would be the equivalent to
//
// $str = (string) 7;
//
// $str === "7"


Another quick example:

$num = 5;

$num := '12';

// Equivalent to
//
// $num = (int) '12';
//
// $num === 12;

So what do you guys think?

If I get a good response I'll look into how to create a proper RFC and
start trying to work out how to implement it.

Many thanks and look forward to some responses,
Tom


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