It (finally) clicked now, 'require' is just a method...
Boy do I feel stupid. 
On another note, though, I also found out that calling amethod(*args) works with anything with 'each' (any Enumerable?), which made me smile. It was the post about ranges that made me get that 
Thanks!
--
Ross Bamford - rosco@roscopeco.remove.co.uk
"\e[1;31mL"
Hi --
It (finally) clicked now, 'require' is just a method...
Boy do I feel stupid.
Don't. That's a pretty traditional rite of passage 
On another note, though, I also found out that calling amethod(*args) works with anything with 'each' (any Enumerable?), which made me smile. It was the post about ranges that made me get that
Interesting. The mind boggles at the side-effect and hard-to-find bug
possibilities But it's quite cool, and I'd never known of it
before.
class E
include Enumerable
def each
3.times {|i| puts "Hello!"; yield i }
end
end
def x(*args)
p *args
end
x(*E.new)
David
On Thu, 1 Dec 2005, Ross Bamford wrote:
--
David A. Black
dblack@wobblini.net
Hi Ross, actually as Florian recently taught me, *obj works for any
object with #to_ary defined --if that is what you mean.
T.
Actually * looks for a to_a.
James Edward Gray II
On Nov 30, 2005, at 7:52 PM, Ross Bamford wrote:
On another note, though, I also found out that calling amethod(*args) works with anything with 'each' (any Enumerable?), which made me smile. It was the post about ranges that made me get that
Actually, I think the * operator looks for #to_a not #to_ary.
Gary Wright
On Nov 30, 2005, at 11:32 PM, Trans wrote:
Hi Ross, actually as Florian recently taught me, *obj works for any
object with #to_ary defined --if that is what you mean.
I see... I was pretty happy when I realised it did it at all, and of course it makes complete sense with hindsight. Thanks for pointing the way.
On Thu, 01 Dec 2005 04:30:28 -0000, Trans <transfire@gmail.com> wrote:
Hi Ross, actually as Florian recently taught me, *obj works for any
object with #to_ary defined --if that is what you mean.T.
--
Ross Bamford - rosco@roscopeco.remove.co.uk
Trans a รฉcrit :
Hi Ross, actually as Florian recently taught me, *obj works for any
object with #to_ary defined --if that is what you mean.T.
AFAIK may change in ruby2.
Actually * looks for a to_a.
Does calling amethod(*x) have the same meaning as calling
amethod(x.to_a)? If is it what is the benefit of using the (less
clear) first way?
Brian Buckley
I was pretty surprised it worked for non-arrays to be honest, so I didn't dare imagine it might be even _more_ flexible. Ruby just keeps on getting better the more I get to know it - I've not been so pleasantly surprised, so often, for a very long time...
Cheers,
On Thu, 01 Dec 2005 13:40:51 -0000, James Edward Gray II <james@grayproductions.net> wrote:
On Nov 30, 2005, at 7:52 PM, Ross Bamford wrote:
On another note, though, I also found out that calling amethod(*args) works with anything with 'each' (any Enumerable?), which made me smile. It was the post about ranges that made me get that
Actually * looks for a to_a.
James Edward Gray II
--
Ross Bamford - rosco@roscopeco.remove.co.uk
"\e[1;31mL"
James Edward Gray II wrote:
On Nov 30, 2005, at 7:52 PM, Ross Bamford wrote:
On another note, though, I also found out that calling amethod (*args) works with anything with 'each' (any Enumerable?), which made me smile. It was the post about ranges that made me get that
Actually * looks for a to_a.
I always thought it looked for to_ary... now someone says it looks
first for to_ary, then to_a.
And I had no idea that it would work with just #each defined.
"Curiouser and curiouser," said Alice.
Hal
Some quick experiments just now suggest it looks first for to_ary, then to_a. As I say, I was pretty pleased to find it did it at all so I didn't carry on playing with it ...
Cheers,
On Thu, 01 Dec 2005 05:45:53 -0000, <gwtmp01@mac.com> wrote:
On Nov 30, 2005, at 11:32 PM, Trans wrote:
Hi Ross, actually as Florian recently taught me, *obj works for any
object with #to_ary defined --if that is what you mean.Actually, I think the * operator looks for #to_a not #to_ary.
Gary Wright
--
Ross Bamford - rosco@roscopeco.remove.co.uk
Hi --
On Thu, 1 Dec 2005, Lionel Thiry wrote:
Trans a รฉcrit :
Hi Ross, actually as Florian recently taught me, *obj works for any
object with #to_ary defined --if that is what you mean.T.
AFAIK may change in ruby2.
As Gary says it's actually to_a, not to_ary -- and I think it will
probably still work in 2.x, because Enumerable#to_a is explicitly
defined (not the soon-to-disappear default to_a for all objects).
David
--
David A. Black
dblack@wobblini.net
Hi --
Actually * looks for a to_a.
Does calling amethod(*x) have the same meaning as calling
amethod(x.to_a)? If is it what is the benefit of using the (less
clear) first way?
They're not the same. * is actually a unary unnary operator:
def x(*args)
p args
end
a = [1,2,3]
x(a) # [[1,2,3,]]
x(*a) # [1,2,3]
David
On Fri, 2 Dec 2005, Brian Buckley wrote:
--
David A. Black
dblack@wobblini.net
It 'unwraps' a supplied [anything] to multiple declared arguments. Imagine:
def amethod(one,two,three)
puts one, two, three
end
If you call that with:
amethod((1..3).to_a)
you'll get an error, because you only supplied one argument - the array. If you specify the '*', however:
amethod(*(1..3))
The range first gets converted to an array with to_a, and then that is expanded into the method's argument list.
You can double-check by specifying either 1..2 or 1..4, which gives an ArgumentError.
On Thu, 01 Dec 2005 15:01:05 -0000, Brian Buckley <briankbuckley@gmail.com> wrote:
Actually * looks for a to_a.
Does calling amethod(*x) have the same meaning as calling
amethod(x.to_a)? If is it what is the benefit of using the (less
clear) first way?Brian Buckley
--
Ross Bamford - rosco@roscopeco.remove.co.uk
"\e[1;31mL"
When I kicked this thread off, I'd just done some quick tests that suggested it worked like above, and on anything with each, and I guessed that (since Enumerable defines to_a, and everything is in terms of each) that it must work that way.
I'm still pretty sure it does to_ary followed by to_a, but as others showed me, it doesn't actually work with just 'each'.
class Clazz
def each
yield 1
yield 2
yield 3
end
end
c = Clazz.new
c = [*c]
p c => [#<Clazz:0xb7f7ccdc>]
That's I think coming from the default to_a, and with the 1.9 snapshot I have it gives a TypeError ('Cannot convert Clazz into Array' - the default to_a is gone). It does _seem_ to work on anything with each if you include Enumerable, but that's because Enumerable defines everything (including to_a) in terms of 'each'. If you add 'include Enumerable' to the class definition above, you get [1,2,3] as expected.
On Fri, 02 Dec 2005 06:13:38 -0000, Hal Fulton <hal9000@hypermetrics.com> wrote:
James Edward Gray II wrote:
On Nov 30, 2005, at 7:52 PM, Ross Bamford wrote:
On another note, though, I also found out that calling amethod (*args) works with anything with 'each' (any Enumerable?), which made me smile. It was the post about ranges that made me get that
Actually * looks for a to_a.
I always thought it looked for to_ary... now someone says it looks
first for to_ary, then to_a.And I had no idea that it would work with just #each defined.
--
Ross Bamford - rosco@roscopeco.remove.co.uk
"\e[1;31mL"
James Edward Gray II wrote:
On another note, though, I also found out that calling amethod (*args) works with anything with 'each' (any Enumerable?), which made me smile. It was the post about ranges that made me get that
Actually * looks for a to_a.
I always thought it looked for to_ary... now someone says it looks
first for to_ary, then to_a.And I had no idea that it would work with just #each defined.
It doesn't:
>> class NoArr
>> def each
>> yield 1
>> yield 2
>> yield 3
>> end
>> undef to_a
>> end
=> nil
>> def multi( one, two, three )
>> p one
>> p two
>> p three
>> end
=> nil
>> multi( *NoArr.new )
NoMethodError: undefined method `to_a' for #<NoArr:0x30d980>
from (irb):14
James Edward Gray II
On Dec 2, 2005, at 12:13 AM, Hal Fulton wrote:
On Nov 30, 2005, at 7:52 PM, Ross Bamford wrote:
David A. Black a รฉcrit :
Hi --
Trans a ๏ฟฝcrit :
Hi Ross, actually as Florian recently taught me, *obj works for any
object with #to_ary defined --if that is what you mean.T.
AFAIK may change in ruby2.
As Gary says it's actually to_a, not to_ary -- and I think it will
probably still work in 2.x, because Enumerable#to_a is explicitly
defined (not the soon-to-disappear default to_a for all objects).David
Mmm, I remember Matz wonders about possible changes in the way the array
expansion operator * could work. He wonders if he should differentiate
array [a,b,c] and list a,b,c or not. Until decided, I keep in mind that
the way *args works may change in ruby2.
On Thu, 1 Dec 2005, Lionel Thiry wrote:
--
Lionel Thiry
Personal web site: http://users.skynet.be/lthiry/
a = [1,2,3]
x(a) # [[1,2,3,]]
x(*a) # [1,2,3]
x(*a) # [1,2,3]
x(a.to_a) # also [1,2,3]
But when might the 1st way (using the unary operator) be preferred to
the more explicit 2nd way?
Brian Buckley
David A. Black wrote:
As Gary says it's actually to_a, not to_ary
#to_ary is called first; if it doesn't exist #to_a will be called.
Hi --
On Thu, 1 Dec 2005, Lionel Thiry wrote:
David A. Black a รฉcrit :
Hi --
On Thu, 1 Dec 2005, Lionel Thiry wrote:
Trans a ๏ฟฝcrit :
Hi Ross, actually as Florian recently taught me, *obj works for any
object with #to_ary defined --if that is what you mean.T.
AFAIK may change in ruby2.
As Gary says it's actually to_a, not to_ary -- and I think it will
probably still work in 2.x, because Enumerable#to_a is explicitly
defined (not the soon-to-disappear default to_a for all objects).David
Mmm, I remember Matz wonders about possible changes in the way the array
expansion operator * could work. He wonders if he should differentiate
array [a,b,c] and list a,b,c or not. Until decided, I keep in mind that
the way *args works may change in ruby2.
Oh, *that* change I forgot about that.
David
--
David A. Black
dblack@wobblini.net
