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Ruby Programming Language
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Syntax suggestion
(I posted this before on the google-group rather than the usenet
group, but it seems not to have shown up. I don't know why. If this is
a duplicate for anyone, my apologies)
def initialize(foo,bar,bat)
@foo,@bar,@bat = foo,bar,bat
end
Seems clumsy and not at all DRY.
What would seem the obvious approach to me would be this:
def initialize(@foo,@bar,@bat)
end
Is there a reason it's not done that way?
jbc wrote: > (I posted this before on the google-group rather than the usenet > group, but it seems not to have shown up. I don't know why. If this is > a duplicate for anyone, my apologies) > def initialize(foo,bar,bat)
> @foo,@bar,@bat = foo,bar,bat
> end
> Seems clumsy and not at all DRY.
> What would seem the obvious approach to me would be this:
> def initialize(@foo,@bar,@bat)
> end
> Is there a reason it's not done that way?
ago.
You can do this:
class Foo
define_method :initialize do |@x,@y,@z| end
end
p Foo.new(1,2,3) # ==> #<Foo:0xb7cce1e4 @x=1, @z=3, @y=2>
You might want to verify that this construct is allowed in 1.9 before
using it heavily. ISTR it is deprecated.
If a method has more than two positional arguments, I tend to look for
alternatives. YMMV of course.
--
vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407
Hi --
On Thu, 7 Jun 2007, Joel VanderWerf wrote: > jbc wrote: >> (I posted this before on the google-group rather than the usenet >> group, but it seems not to have shown up. I don't know why. If this is >> a duplicate for anyone, my apologies) >> def initialize(foo,bar,bat)
>> @foo,@bar,@bat = foo,bar,bat
>> end
>> Seems clumsy and not at all DRY.
>> What would seem the obvious approach to me would be this:
>> def initialize(@foo,@bar,@bat)
>> end
>> Is there a reason it's not done that way?
> This has been discussed on ruby-talk, but it might have been a few years ago.
http://oldrcrs.rubypal.com/rejected.html#rcr3
David
--
Q. What is THE Ruby book for Rails developers?
A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black)
(See what readers are saying! http://www.rubypal.com/r4rrevs.pdf)
Q. Where can I get Ruby/Rails on-site training, consulting, coaching?
A. Ruby Power and Light, LLC (http://www.rubypal.com)
On Jun 7, 12:29 am, Joel VanderWerf <v@path.berkeley.edu> wrote:
> class Foo > define_method :initialize do |@x,@y,@z| end > end > p Foo.new(1,2,3) # ==> #<Foo:0xb7cce1e4 @x=1, @z=3, @y=2>
> You might want to verify that this construct is allowed in 1.9 before
> using it heavily. ISTR it is deprecated.
Not just the specific case above, but the general functionality that
block parameters can be instance variables, setting the instance
variable as a side-effect of just invoking the block. For example:
p @a
#=> nil
3.times{ |@a| }
p @a
#=> 2
p VERSION
#=> "1.8.5"
On 6/7/07, Phrogz <g@refinery.com> wrote:
<snip>
> Can someone confirm or deny that this is deprecated in 1.9?
I remember Matz saying some times ago that it is deprecated. I did not
post this before b/c I just cannot come up with a URL :(
But I remember distinctively as I really liked the syntax :((
Robert
--
You see things; and you say Why?
But I dream things that never were; and I say Why not?
-- George Bernard Shaw
Phrogz wrote: > On Jun 7, 12:29 am, Joel VanderWerf <v @path.berkeley.edu> wrote: >> class Foo >> define_method :initialize do |@x,@y,@z| end >> end >> p Foo.new(1,2,3) # ==> #<Foo:0xb7cce1e4 @x=1, @z=3, @y=2>
>> You might want to verify that this construct is allowed in 1.9 before
>> using it heavily. ISTR it is deprecated.
> Can someone confirm or deny that this is deprecated in 1.9?
$ ruby1.9 -e '
class Foo
define_method(:initialize) do |@x,@y,@z| end
end'
formal argument cannot be an instance variable
define_method(:initialize) do |@x,@y,@z| end
Daniel
On 07.06.2007 07:42, jbc wrote:
> (I posted this before on the google-group rather than the usenet > group, but it seems not to have shown up. I don't know why. If this is > a duplicate for anyone, my apologies) > def initialize(foo,bar,bat)
> @foo,@bar,@bat = foo,bar,bat
> end
> Seems clumsy and not at all DRY.
> What would seem the obvious approach to me would be this:
> def initialize(@foo,@bar,@bat)
> end
> Is there a reason it's not done that way?
Foo = Struct.new :foo, :bar, :bat
f=Foo.new 1,2,3
You'll also get comparison logic and hashing for free. And you can even
define methods on the class directly like this:
Foo = Struct.new :foo, :bar, :bat do
def size
foo + bar + bat
end
end
I use that pretty often because it saves even more typing than just the
initialize code. :-)
Kind regards
robert
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