Finding the instance reference of an object

greg greg at cosc.canterbury.ac.nz
Sun Nov 9 11:11:28 CET 2008


Steven D'Aprano wrote:

> Not according to my Comp Sci lecturers back in the day, and not according 
> to my Pascal books.

Pascal books will tell you what call-by-value means
in Pascal. You can't just blindly take that description
and apply it to other languages, just as you can't
take what your Pascal book says about assigment and
apply it blindly to Python without getting into
trouble.

Describing call-by-value as "copying the value" works
in Pascal, because "assignment" and "copy" are synonyms
in that language. But they're not synonyms in all
languages, so a language-independent definition of
call-by-value needs to describe it in a more general
way.

Refusing to accept that a more general definition
exists just because it's not mentioned in your Pascal
book is a little absurd.

-- 
Greg



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