Steve D'Aprano <steve+pyt...@pearwood.info> writes:
> On Thu, 17 Aug 2017 08:29 am, Mok-Kong Shen wrote:
>
> > I have earlier learned some other (older) programming languages. For
> > these the formal parameters are either "by reference" or "by value".
>
> By reference and by value are not the only two conventions.
>
> Perhaps if you go back to the 1950s you might be able to argue that
> "reference" and "value" are the only two conventions, but alternatives
> have existed for many decades, since *at least* 1960 when Algol
> introduced "call by name".
Indeed. I have had a lot of success helping people, who come to Python
with the baggage of that false dichotomy, by using Fredrik Lundh's term
“call by object” to describe the Python argument-pass semantics.
Python’s model is neither “call by value” nor “call by reference”
(because any attempt to use those terms for Python requires you to
use non-standard definitions of the words “-value” and
“-reference”). The most accurate description is CLU’s “call by
object” or “call by sharing“. Or, if you prefer, “call by object
reference“.
<URL:http://www.effbot.org/zone/call-by-object.htm>
> This may help:
>
> http://import-that.dreamwidth.org/1130.html
That's a good one too, thank you for writing it. I just wish Dreamwidth
would present a URL with a slug derived from the article title, so that
it was easier to search the URLs in my history :-)
--
\ “Some people have a problem, and they think “I know, I'll use |
`\ Perl!”. Now they have some number of problems but they're not |
_o__) sure whether it's a string or an integer.” —Benno Rice, 2011 |
Ben Finney
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