For one thing, what if a variable is passed in? We don’t want it to
fail
just because the array is empty.
well this is not exactly the case simon described though is it?
method # empty array as arg
method * # NO args!
Well, I meant more like this case:
myvar = mymethod # mymethod returns an array… possibly empty
meth2(*myvar) # Pass that array as individual args
so, it’s not that the method is failing just because an empty array is
passed
in, it is failing because an empty array was exploded, yielding and
non-existent parameter list. i may be in the minority, but it’s not THAT
counter intuitive for me that attempting to call a method expecting args,
with
no args, should be an error.
The asterisk (or star or splat) is a special case.
I can’t think of a case where Ruby generates a
“number of params” type of error for a method where
star is specified where the method is defined.
On the other hand, I am simply assuming that there
is a star on the definition. There certainly is one
on the call… they usually go together, UNLESS you
are expanding an array of known size, resulting in
exactly N parameters.
For another thing, consider what happens with
strings. foo = “value” + “” should not be
illegal, I think.
no, of course not. but this is analogous to the first example above, not
the
second one, which would be more along the lines of
foo = “value” + *“”
if ‘*String’ did, for example, an explosion into a list of Fixnums (chars)
or
something like that…
Well, I see what you mean. But they are analogous in
this sense: Given a collection of entities, add another
entity that is a “null” with respect to the context of
that collection and its add operation.
Pushing an empty list of items onto an array doesn’t
change the array, just as adding a null string onto
a string doesn’t change that string; except that we
are actually doing an assignment where the string
is concerned – better to make it a <<. Boy, this is
getting more and more nitpicky, isn’t it?
The bottom line, to me, is that if there is a star
in the definition AND in the caller, the idea of
“expanding” the array is almost meaningless.
Is there ever a real difference in these two situations?
(See below.) There probably is something I’m overlooking,
of course.
def meth1(*args)
#…
end
meth1(*myarray)
def meth2(args)
#…
end
meth2(myarray)
Cheers,
Hal
···
----- Original Message -----
From: “ahoward” ahoward@fsl.noaa.gov
Newsgroups: comp.lang.ruby
To: “ruby-talk ML” ruby-talk@ruby-lang.org
Sent: Tuesday, June 17, 2003 4:07 PM
Subject: Re: [RCR] Array#push(empty array expanded) => no exception
