On 7/9/20 1:28 AM, John W. Eaton wrote:
Bug report 58695 raised the following issue.
Currently, Octave allows function to be called with more input or output
arguments than can possibly be used or created. For example,
function f (), end
may be called as
f (1)
or
x = f () ## You do get a warning here
[1, f, 2] ## But not here...
I think the original intent in Octave was to allow the call warn or
attempt to do something reasonable (if possible) when no outputs are
created. So I could see a reasonable argument made for allowing this
kind of behavior but I don't know why I thought this was a good thing to
do and it seems reasonable to have the interpreter detect these types of
argument number mismatches automatically.
I think Matlab always throws an error if a function is called with more
input or output arguments than can possibly be used or generated so this
would improve compatibility somewhat.
Should we change Octave's behavior to match Matlab? Always? Just when
using --traditional mode?
jwe
Previously, I tried to fix bug #58686, where a scenario showed up, that
should always make Octave follow the Matlab approach in this regard.
The short outline is, assert() can be called in two ways
assert (expr)
assert (val, expected)
Now I made a test like this with your example
assert (f(1), 42)
Because f() returns nothing the call was (without warning or error)
interpreted as
assert (42) == assert (true)
and passed Octave's test suite en perfect, even my function did not work
at all.
Thus with silent argument ignoring it is easily possible to create super
trivial mistakes, which are a nightmare to detect and to debug as the
code grows and Octave's test suite is of no help then.
I vote to always follow the behavior of Matlab in this case or at least
to throw a warning.