Re: Implicit class construction, _cast() and `=()

I think the cast lfun interface has to be expanded a bit as well. If we do (A)B then the cast method in B should get the program A as second argument, I think.

I agree.

Further, if B has no cast method, should some ``cast (or even create) in A be called? Example: (Gmp.mpz)5 would then result in Gmp.mpz(5).

I don't think it's a good idea to reuse the create lfun for that since that'd mean create() could be used in a situation the class author probably didn't expect. A right-cast operator lfun seems like a logical extension, though. The best would be if proper static functions are implemented so that

(A) b

is tried as the equivalent of

A.``cast (b)

and not

(tmp = A(), tmp->``cast (b), tmp)

That would allow ``cast to return an existing object.

/ Martin Stjernholm, Roxen IS

Previous text:

2003-05-06 16:08: Subject: Re: Implicit class construction, _cast() and `=()

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I think the cast lfun interface has to be expanded a bit as well. If we do (A)B then the cast method in B should get the program A as second argument, I think. Further, if B has no cast method, should some ``cast (or even create) in A be called? Example: (Gmp.mpz)5 would then result in Gmp.mpz(5).

/ Martin Nilsson (lambda)