Using string variable to call a method

ruby-talk
1

Hello all,

How can I use a string variable as part of a method name I'm calling? For
example say I want to call the method say_hello using the following:

def say_hello
  puts "Hello!"
end

str = "hello"

say_???

Thanks in advance!! -- BTR

2

Alle lunedì 7 gennaio 2008, Bryan Richardson ha scritto:

Hello all,

How can I use a string variable as part of a method name I'm calling? For
example say I want to call the method say_hello using the following:

def say_hello
  puts "Hello!"
end

str = "hello"

say_???

Thanks in advance!! -- BTR

send "say_#{str}"

Stefano

3

You can use: eval, instance_eval, class_eval, module_eval oder send
The different evals are described here:
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/192513
(click on the "N" to read the next message in the thread)
send is as far as I understand it, used to send messages to objects.
Keep in mind that method calls are messages send to objects.

4

In general, the send method is preferred over evalling a string when
possible.

In addition to send "say_#{str}", you can do method("say_#{str}".to_sym)
.call.

Dan

···

On 1/7/08, Thomas Wieczorek <wieczo.yo@googlemail.com> wrote:

You can use: eval, instance_eval, class_eval, module_eval oder send
The different evals are described here:
http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/192513
(click on the "N" to read the next message in the thread)
send is as far as I understand it, used to send messages to objects.
Keep in mind that method calls are messages send to objects.

5

Along these same lines, is it possible to do a require and include
dynamically, getting the name of the file to require and module to include
from a string?

···

On Jan 7, 2008 5:25 PM, Daniel Finnie <danfinnie@optonline.net> wrote:

In general, the send method is preferred over evalling a string when
possible.

In addition to send "say_#{str}", you can do method("say_#{str}".to_sym)
.call.

Dan

On 1/7/08, Thomas Wieczorek <wieczo.yo@googlemail.com> wrote:
>
> You can use: eval, instance_eval, class_eval, module_eval oder send
> The different evals are described here:
> http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/192513
> (click on the "N" to read the next message in the thread)
> send is as far as I understand it, used to send messages to objects.
> Keep in mind that method calls are messages send to objects.
>
>

6

require is obvious, the method takes a string already.

Including a module, I think you can do:

ClassName.send(:include, Module.const_get("ModuleName"))

or if you're working with an instance variable, replace :include with
:extend.

Jason

···

On Jan 8, 2008 5:25 PM, Bryan Richardson <btricha@gmail.com> wrote:

Along these same lines, is it possible to do a require and include
dynamically, getting the name of the file to require and module to include
from a string?

On Jan 7, 2008 5:25 PM, Daniel Finnie <danfinnie@optonline.net> wrote:

> In general, the send method is preferred over evalling a string when
> possible.
>
> In addition to send "say_#{str}", you can do method("say_#{str}".to_sym)
> .call.
>
> Dan
>
>
> On 1/7/08, Thomas Wieczorek <wieczo.yo@googlemail.com> wrote:
> >
> > You can use: eval, instance_eval, class_eval, module_eval oder send
> > The different evals are described here:
> > http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/192513
> > (click on the "N" to read the next message in the thread)
> > send is as far as I understand it, used to send messages to objects.
> > Keep in mind that method calls are messages send to objects.
> >
> >
>

7

send :include, Module.const_get(ARGV[1]) worked. Thanks!!

···

On Jan 8, 2008 3:47 PM, Jason Roelofs <jameskilton@gmail.com> wrote:

require is obvious, the method takes a string already.

Including a module, I think you can do:

ClassName.send(:include, Module.const_get("ModuleName"))

or if you're working with an instance variable, replace :include with
:extend.

Jason

On Jan 8, 2008 5:25 PM, Bryan Richardson <btricha@gmail.com> wrote:

> Along these same lines, is it possible to do a require and include
> dynamically, getting the name of the file to require and module to
include
> from a string?
>
> On Jan 7, 2008 5:25 PM, Daniel Finnie <danfinnie@optonline.net> wrote:
>
> > In general, the send method is preferred over evalling a string when
> > possible.
> >
> > In addition to send "say_#{str}", you can do
method("say_#{str}".to_sym)
> > .call.
> >
> > Dan
> >
> >
> > On 1/7/08, Thomas Wieczorek <wieczo.yo@googlemail.com> wrote:
> > >
> > > You can use: eval, instance_eval, class_eval, module_eval oder send
> > > The different evals are described here:
> > > http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/192513
> > > (click on the "N" to read the next message in the thread)
> > > send is as far as I understand it, used to send messages to objects.
> > > Keep in mind that method calls are messages send to objects.
> > >
> > >
> >
>