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Date: Sun, 12 Dec 2021 18:29:04 +0000
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Subject: Re: [PHP-DEV] [RFC] User Defined Operator Overloads (v0.6)
From: rowan.collins@gmail.com (Rowan Tommins)

On 12/12/2021 17:32, Larry Garfield wrote:
>> The only mitigation for unnecessary complexity I can think of is to force
>> overloaded operators to be "arrow functions" to encourage only minimal
>> code, e.g.
>>
>> operator +(Number $other, OperandPosition $operandPos): Number => return
>> new Number ($this->value + $other->value);
> I don't think that would be possible.  As many of the examples in the RFC show, there are numerous cases where an operator function/callback/thing will need branching logic internally.  Even if we did that, people could just sub-call to a single function which would be just as complex as if it were in the operator callback directly.


I don't know if this would actually be helpful, but you could *force* 
the operator definition to be an alias for a normal method. That would 
(at least partially) solve the "dynamic call" problem, because the 
underlying method would be available with the existing dynamic call syntax.

Perhaps we could use an Attribute to bind the operator to the method, 
which would also reduce the impact on tools that need to parse class 
definitions:

class  Collection{ #[Operator('+')]
     public function  union(Collection$other,  OperandPosition$operandPos)  {}
}

An interesting extension would be to have an optional argument to the 
Attribute which binds separate methods for each direction of arguments, 
rather than exposing it as a parameter:

class  Number{ #[Operator('/', OperandPosition::LeftSide)]
     public function  divideBy(Number $divisor)  {}

#[Operator('/', OperandPosition::RightSide)]
     publicfunction  fractionOf(Number $dividend)  {}
}


Regards,

-- 
Rowan Tommins
[IMSoP]