Re: Ok sorry, it is just a book gives no feedback.

[Robert Dewar <robert_dewar@my-deja.com>]

In article <931r2l$4ai5t$2@ID-25716.news.dfncis.de>,
  "Nick Roberts" <nickroberts@callnetuk.com> wrote:

> My own opinion is that, generally, functions should have no
> side effects

This principle is in general a reasonable one, but it is not
easy to define what this means. Nick goes on to give an
explanation, but his explanation is wrong, it would forbid
many functions, e.g. anything that allocates and returns a
pointer, which is far too severe.

Getting the explanation right is very hard (which is why the
language does not attempt to enforce this). For example,
memo functions clearly violate Nick's rules, but should be
allowed.

Also Nick's definition would not allow any instrumentation of
functions, and that's wrong too.

In any case, the answer is far afield from the question, at the
level the question is asked, the answer is

use a function if a value is returned
use a procedure if no value is returned

(yes that's not quite right either, but the question is not
about subtle semantics and language design, it is more in the
realm of "I don't understand any of this stuff, help!!!" :-)




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