Is it behaving strange?

Ruby
21

On 2/16/07, Peña, Botp [email protected] wrote:

so this is allowed,
(irb):53: syntax error, unexpected ‘,’, expecting ‘=’ b,*a,c=1,2,3,4
irb(main):054:0>

ruby, is telling me that “*a” is a blackhole. The c does “not matter”.
Botp

this is a very nice analogy, however it does only hold for the LHS
i.e. assignment target and formal parameter lists.
On the LHS a splatted expression is an infinite consumer a blackhole
:wink:
On the RHS a splatted expression is a finite producer though.
I see no reason why …, *a, … should be forbidden on the RHS.
to … = *(a + [b])
I’d prefer
… = *a, b

Side note to David:
after a night of consideration I do not believe that there any
syntactical problems
the splat operator already being allowed in front of parenthesis.

so is this one,

irb(main):056:0> *a
SyntaxError: compile error
(irb):56: syntax error, unexpected ‘\n’, expecting ‘=’

that’s a blackhole without a hole or opening. feed it :slight_smile:
as mentioned above we are in the producer case here
again, another stupid blackhole reasoning.
I would not go that far :wink:

nonetheless, splat is a very sweet yet too powerful operator.
I feel that splat op digress oo-ness. But i believe it’s not oo for
oo’s sake. It’s solving problems and discovering brilliant solutions.
Ruby does it w ease and fun. Sometimes, i feel ruby will trend toward
object and method unification, wherein objects can be methods and vice
versa. arggh, like matter <==> energy. maybe, a superproc or
superlamdba in the future… i’ll stop now :slight_smile:
You might have a point though :wink:

drive w caution, (black)holes ahead.

sorry for the long post fr a nuby.
kind regards -botp

Cheers
Robert

22

Hi –

On Fri, 16 Feb 2007, sur max wrote:

definitely, it seems so natural using

= *a,b

and this gives the feel of ruby.

isn’t it ?

A bug report has been submitted for this:

irb(main):001:0> a = [1,2]
=> [1, 2]
irb(main):002:0> b = *a, 3
=> [1, 2]

in 1.9.

David

23

Hi,

In message “Re: is it behaving strange ?”
on Fri, 16 Feb 2007 04:45:38 +0900, [email protected] writes:

|irb(main):001:0> a = [9,5]
|=> [9, 5]
|irb(main):002:0> b = 9,5,6
|=> [9, 5, 6]
|irb(main):003:0> b = *a, 6
|=> [9, 5]
|irb(main):004:0> b = [*a, 6]
|=> [9, 5, 6]
|
|I don’t really understand the third one. I would have expected it to
|be the same as the second. I haven’t tried a more recent 1.9 version,
|though – maybe it’s been changed.

You don’t understand because it’s a bug. I will fix it soon.

          matz.
24

Hi –

On Fri, 16 Feb 2007, Yukihiro M. wrote:

|=> [9, 5]
|irb(main):004:0> b = [*a, 6]
|=> [9, 5, 6]
|
|I don’t really understand the third one. I would have expected it to
|be the same as the second. I haven’t tried a more recent 1.9 version,
|though – maybe it’s been changed.

You don’t understand because it’s a bug. I will fix it soon.

Cool, thanks.

David

25

fr: sur max [mailto:[email protected]]

definitely, it seems so natural using

= *a,b

indeed, as robert pointed out.
but the magic generally leans towards, producing (and thereby
questioning) *a, like

def x
*a
end

or

def x
1,2,3
end

so what does *a produce, or 1,2,3? an array, a list, or an unarrayed
array (to quote dblack)? those are just names, but what is it really,
what are its properties/methods/etc?

and this gives the feel of ruby. isn’t it ?

i’m not sure (because the magic tends to fall on hole, a cul de sac),
maybe because i seldom use it, … only matz knows.

kind regards -botp

26

On 2/17/07, Peña, Botp [email protected] wrote:

i’m not sure (because the magic tends to fall on hole, a cul de sac), maybe because i seldom use it, … only matz knows.
Take a look at these

instruments = {‘trombones’ => 1, ‘clarinets’ => 2}
p instruments.to_a
[[“trombones”, 1], [“clarinets”, 2]]
p *instruments
[“trombones”, 1]
[“clarinets”, 2]

Normally * uses to_a or to_ary, but certainly its more devious than it
appears. And where exactly is this operator defined in ruby source
tree? eval.c ?

27

Hi –

On Sat, 17 Feb 2007, hemant wrote:

appears. And where exactly is this operator defined in ruby source
tree? eval.c ?

I’m not sure I’m seeing what you’re getting at in your example. Isn’t
that what you’d expect it to do?

David

28

On 2/17/07, hemant [email protected] wrote:

end

There was only one Road; that it was like a great river: its springs
were at every doorstep, and every path was its tributary.
http://people.inxsasia.com/~hemant

I really start to love Smalltalk’s syntax more and more…
Maybe sometimes less is more.
Than OTOH what fun Quiz113 was!
But fun can be dangerous I guess :frowning:

Cheers
Robert