(j3.2006) Chaining type-bound procedure references

Malcolm Cohen malcolm
Wed Apr 30 19:37:13 EDT 2014

On several occasions, and today in particular, I have encountered the situation 
where it would be clearer (and definitely easier) to implement an algorithm in 
the following fashion:

val = obj % method1() % method2()

Here method1() returns some object, and method2() is bound to class of that 
object.   And I realize of course that the language does not (currently) permit 
anything like this.

   MODULE PROCEDURE do_method2_on_something

FUNCTION do_method2_on_something(something) RESULT(r)
declare the result
CLASS(someobject) something
r = something%method2

val = method2(obj%method1())

Yes this "pollutes" the namespace slightly, and you *might* need a helper 
function (though the way we've done object orientation you can have a single 
function that will be both a normal function and type-bound) but the invocation 
is simple.

I can guess that there are some inherent ambiguities that make my syntax above 
non starters, though I cannot readily think of what the are.

I don't think we can do this without opening the floodgates to
which we decided against doing long ago.

And it does seem like a pretty big feature that does little more than provide 
alternative syntax for something we can do easily already.

................................Malcolm Cohen, Nihon NAG, Tokyo. 

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