[lnkForumImage]
TotalShareware - Download Free Software
Confronta i prezzi di migliaia di prodotti.
Asp Forum
 Home | Login | Register | Search 


 

Forums >

comp.lang.ruby

method_missing and assignment

Patrick Gundlach

6/3/2005 7:28:00 PM

Hi,

with ruby 1.8.2:
--------------------------------------------------
class A
def method_missing (a,*b)
# do something
end
end


a=A.new
a.foo("bar","baz")
a.foo=("bar","baz")
--------------------------------------------------

the last line gives me an error

-:11: syntax error
a.foo=("bar","baz")
^

Any way I can assign multiple values in a natural way with
method_missing? Or would you suggest to use an array that holds
multiple data?

Regards,

Patrick
5 Answers

Joel VanderWerf

6/3/2005 8:11:00 PM

0

Patrick Gundlach wrote:
> Hi,
>
> with ruby 1.8.2:
> --------------------------------------------------
> class A
> def method_missing (a,*b)
> # do something
> end
> end
>
>
> a=A.new
> a.foo("bar","baz")
> a.foo=("bar","baz")
> --------------------------------------------------
>
> the last line gives me an error
>
> -:11: syntax error
> a.foo=("bar","baz")
> ^
>
> Any way I can assign multiple values in a natural way with
> method_missing? Or would you suggest to use an array that holds
> multiple data?
>
> Regards,
>
> Patrick

It's not particularly a property of method_missing--you can't even
define a method to do this:

irb(main):001:0> def foo=(a,b); end
=> nil
irb(main):002:0> self.foo=(1,2)
SyntaxError: compile error
(irb):2: syntax error
self.foo=(1,2)
^
from (irb):2
irb(main):003:0>

Patrick Gundlach

6/3/2005 8:33:00 PM

0


[...]

> It's not particularly a property of method_missing--you can't even
> define a method to do this:
>
> irb(main):002:0> self.foo=(1,2)
> SyntaxError: compile error
> (irb):2: syntax error
> self.foo=(1,2)
> ^
> from (irb):2

I should have tested the obvoius, thanks for this out.

but something like method=(1,2) could be handy, for example for
assigning complex numbers.

Thanx,

Patrick

Gavin Kistner

6/3/2005 9:11:00 PM

0

On Jun 3, 2005, at 2:05 PM, Patrick Gundlach wrote:
> the last line gives me an error
>
> -:11: syntax error
> a.foo=("bar","baz")
> ^


a.foo = ["bar","baz"];

You cannot have more than one value on the right side of a call to a
method whose name ends in =.

(But you can do:
a.foo, b.foo = "bar", "baz"
which is the same as:
a.foo = "bar"
b.foo = "baz"

Eric Mahurin

6/3/2005 9:29:00 PM

0

--- Patrick Gundlach <clr5.10.randomuser@spamgourmet.com>
wrote:

>
> [...]
>
> > It's not particularly a property of method_missing--you
> can't even
> > define a method to do this:
> >
> > irb(main):002:0> self.foo=(1,2)
> > SyntaxError: compile error
> > (irb):2: syntax error
> > self.foo=(1,2)
> > ^
> > from (irb):2
>
> I should have tested the obvoius, thanks for this out.
>
> but something like method=(1,2) could be handy, for example
> for
> assigning complex numbers.
>
> Thanx,
>
> Patrick

The above isn't valid syntax because it is being parsed as an
assignment (not a method call) and (1,2) is not a valid
expression (RHS).

If you need something more complex, you can just assign with an
array:

self.foo = [1,2]

There is an RCR open to attempt to be able to do this type of
thing:

self.foo(*args) = value

which gets interpreted as self."foo="(*args,value). This is
similar to the []= operator.




__________________________________
Discover Yahoo!
Use Yahoo! to plan a weekend, have fun online and more. Check it out!
http://discover....

Patrick Gundlach

6/3/2005 10:10:00 PM

0


[...]

> The above isn't valid syntax because it is being parsed as an
> assignment (not a method call) and (1,2) is not a valid
> expression (RHS).

OK, I see.


> If you need something more complex, you can just assign with an
> array:
>
> self.foo = [1,2]

This is the solution where I first thought of as a workaround. But it
looks ok to me now.


Thanks,

Pat