Just spinning wheels this evening...
Why does #instance_variable_get/set require an "@" sign in front of
the variable name? It's not like there is any other valid instance
variable name, is there?
And why can't #instance_variable_set take a hash to set more than one
variable at a time?
T.
Hi,
Why does #instance_variable_get/set require an "@" sign in front of
the variable name? It's not like there is any other valid instance
variable name, is there?
Because it's part of a method name.
And why can't #instance_variable_set take a hash to set more than one
variable at a time?
I don't think it makes programs cleaner.
matz.
In message "Re: instance_variable_[gs]et" on Thu, 27 Mar 2008 13:36:23 +0900, Trans <transfire@gmail.com> writes:
By the way, if you really need it, it is easily implemented on your own:
Example:
def set_instance_variables(variables)
variables.each do |key, value|
instance_variable_set("@#{key}", value)
end
end
Greetings
Florian
On Mar 27, 2008, at 5:36 AM, Trans wrote:
And why can't #instance_variable_set take a hash to set more than one
variable at a time?T.
There are, but you can only get to them from C.
On Mar 26, 2008, at 21:36 PM, Trans wrote:
Just spinning wheels this evening...
Why does #instance_variable_get/set require an "@" sign in front of
the variable name? It's not like there is any other valid instance
variable name, is there?
Yes, of course. Facets has #instance_assign, but it just seems
wasteful when one method could do.
I don't quite get matz take. How is
variables.each do |key, value|
instance_variable_set("@#{key}", value)
end
cleaner than
instance_variable_set(variables)
T.
On Mar 27, 8:23 am, Florian Gilcher <f...@andersground.net> wrote:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1On Mar 27, 2008, at 5:36 AM, Trans wrote:
> And why can't #instance_variable_set take a hash to set more than one
> variable at a time?> T.
By the way, if you really need it, it is easily implemented on your own:
Example:def set_instance_variables(variables)
variables.each do |key, value|
instance_variable_set("@#{key}", value)
end
end
Sorry matz, I don't follow. What is "it" and what method name?
T.
On Mar 27, 12:43 am, Yukihiro Matsumoto <m...@ruby-lang.org> wrote:
Hi,
In message "Re: instance_variable_[gs]et" > on Thu, 27 Mar 2008 13:36:23 +0900, Trans <transf...@gmail.com> writes:
>Why does #instance_variable_get/set require an "@" sign in front of
>the variable name? It's not like there is any other valid instance
>variable name, is there?Because it's part of a method name.
How often is that really needed? I can remember only few cases where I needed that - and those were probably more experimental.
Kind regards
robert
On 27.03.2008 16:28, Trans wrote:
On Mar 27, 8:23 am, Florian Gilcher <f...@andersground.net> wrote:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1On Mar 27, 2008, at 5:36 AM, Trans wrote:
And why can't #instance_variable_set take a hash to set more than one
variable at a time?
T.By the way, if you really need it, it is easily implemented on your own:
Example:def set_instance_variables(variables)
variables.each do |key, value|
instance_variable_set("@#{key}", value)
end
endYes, of course. Facets has #instance_assign, but it just seems
wasteful when one method could do.I don't quite get matz take. How is
variables.each do |key, value|
instance_variable_set("@#{key}", value)
endcleaner than
instance_variable_set(variables)
It won't but he didn't say that. And Florian Gilcher showed you that
you can write your own method that do it for you. I don't think that
Ruby should have built-in such a method. Using
instance_variable_[sg]et should be very rare (for example in
metaprogramming) and using such a loop even more.
On Thu, Mar 27, 2008 at 4:28 PM, Trans <transfire@gmail.com> wrote:
I don't quite get matz take. How is
variables.each do |key, value|
instance_variable_set("@#{key}", value)
endcleaner than
instance_variable_set(variables)
--
Radosław Bułat
http://radarek.jogger.pl - mój blog
Robert Klemme wrote:
...
I don't quite get matz take. How is
variables.each do |key, value|
instance_variable_set("@#{key}", value)
endcleaner than
instance_variable_set(variables)
How often is that really needed? I can remember only few cases where I needed that - and those were probably more experimental.
I've got a couple of methods in library code I use frequently that initialize or populate an object from a hash using the loop above. I've always thought it was kind of a pain (and inefficient) to have to construct a string for each key.
Why couldn't #instance_variable_set be agnostic about whether you refer to ivars as "foo" or "@foo" ? I don't see any ambiguity...
On 27.03.2008 16:28, Trans wrote:
--
vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407
As a DSL implementor I could not disagree more with you, obviously
there are many people who wrote the same code
each { |k,v|
ivar_set "@#{k}", v
that would mean that it would be a nice feature to have, it would
simply be the most DRY solution to the problem (or DROP in this case).
Cheers
Robert
2008/3/27 Radosław Bułat <radek.bulat@gmail.com>:
On Thu, Mar 27, 2008 at 4:28 PM, Trans <transfire@gmail.com> wrote:
> I don't quite get matz take. How is
>
>
> variables.each do |key, value|
> instance_variable_set("@#{key}", value)
> end
>
> cleaner than
>
> instance_variable_set(variables)It won't but he didn't say that. And Florian Gilcher showed you that
you can write your own method that do it for you. I don't think that
Ruby should have built-in such a method. Using
instance_variable_[sg]et should be very rare (for example in
metaprogramming) and using such a loop even more.
--
http://ruby-smalltalk.blogspot.com/
---
Whereof one cannot speak, thereof one must be silent.
Ludwig Wittgenstein
I've got a couple of methods in library code I use frequently that
initialize or populate an object from a hash using the loop above. I've
always thought it was kind of a pain (and inefficient) to have to
construct a string for each key.
Does it mean that everyone use/need it? I don't think so.
Why couldn't #instance_variable_set be agnostic about whether you refer
to ivars as "foo" or "@foo" ? I don't see any ambiguity...
I don't know if it's main reason but AFAIR Ruby internally use
instance variables without "@" character to store additional
information about object (but from Ruby you can't get it).
I think that most important is consistent. We use @ in code and the
same goes when we want get value by instance_variable_get method.
On Thu, Mar 27, 2008 at 9:07 PM, Joel VanderWerf <vjoel@path.berkeley.edu> wrote:
--
Radosław Bułat
http://radarek.jogger.pl - mój blog
Radosław Bułat wrote:
I've got a couple of methods in library code I use frequently that
initialize or populate an object from a hash using the loop above. I've
always thought it was kind of a pain (and inefficient) to have to
construct a string for each key.Does it mean that everyone use/need it? I don't think so.
Don't see what that has to do with anything. There's lots of core methods that are rarely used. Have you used Module:protected_method_defined? recently?
Why couldn't #instance_variable_set be agnostic about whether you refer
to ivars as "foo" or "@foo" ? I don't see any ambiguity...I don't know if it's main reason but AFAIR Ruby internally use
instance variables without "@" character to store additional
information about object (but from Ruby you can't get it).
That's a good point, but my suggestion was for #instance_variable_set to map both "foo" and "@foo" to the same entry in the table, namely the entry for "@foo". Hidden entries would remain hidden.
I think that most important is consistent. We use @ in code and the
same goes when we want get value by instance_variable_get method.
Maybe.
On Thu, Mar 27, 2008 at 9:07 PM, Joel VanderWerf > <vjoel@path.berkeley.edu> wrote:
--
vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407