How to pass a function as parameter?

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From: Fritz Trapper on 30 Dec 2009 06:42

---

I want to pass a reference to function as parameter to another function
and execute the passed function. Somthing like this:

def executer(func)
func(1)
end

def test(x)
p x
end

executer(test)

How to write this correctly in ruby?
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From: Marvin Gülker on 30 Dec 2009 06:48

---

Fritz Trapper wrote:
> I want to pass a reference to function as parameter to another function
> and execute the passed function. Somthing like this:
>
> def executer(func)
> func(1)
> end
>
> def test(x)
> p x
> end
>
> executer(test)
>
> How to write this correctly in ruby?

Are you looking for the #method method?
----------------------------------------
irb(main):001:0> def a
irb(main):002:1> puts "hello"
irb(main):003:1> end
=> nil
irb(main):004:0> def b(f)
irb(main):005:1> f.call
irb(main):006:1> end
=> nil
irb(main):007:0> m = method(:a)
=> #<Method: Object#a>
irb(main):008:0> b(m)
hello
=> nil
irb(main):009:0>
------------------------------------------

Marvin
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From: Jesús Gabriel y Galán on 30 Dec 2009 06:51

---

On Wed, Dec 30, 2009 at 12:42 PM, Fritz Trapper <ajfrenzel(a)web.de> wrote:
> I want to pass a reference to function as parameter to another function
> and execute the passed function. Somthing like this:
>
> def executer(func)
>   func(1)
> end
>
> def test(x)
>   p x
> end
>
> executer(test)
>
> How to write this correctly in ruby?

A typical way would be using blocks or procs:

def executer
yield 1
end

executer {|x| puts "I got #{x}"}

If you want something to handle around in a variable:

func = lambda {|x| puts "I got #{x}"}
executer(&func) # => I got 1

Or if in the executer you want to store the block for later use:

def executer(&block)
@save_for_later = block
end

#later...
@save_for_later.call(1) #or @save_for_later[1]

Hope this helps,

Jesus.

From: Jeff Peng on 30 Dec 2009 07:00

---

Jes�s Gabriel y Gal�n:
> On Wed, Dec 30, 2009 at 12:42 PM, Fritz Trapper <ajfrenzel(a)web.de> wrote:
>> I want to pass a reference to function as parameter to another function
>> and execute the passed function. Somthing like this:
>>
>> def executer(func)
>> func(1)
>> end
>>
>> def test(x)
>> p x
>> end
>>
>> executer(test)
>>
>> How to write this correctly in ruby?
>
> A typical way would be using blocks or procs:
>
> def executer
> yield 1
> end
>
> executer {|x| puts "I got #{x}"}
>
> If you want something to handle around in a variable:
>
> func = lambda {|x| puts "I got #{x}"}
> executer(&func) # => I got 1
>

for &func, what's the "&" before "func" here?

Thanks.

From: Fritz Trapper on 30 Dec 2009 07:08

---

Thanks for your quick replies.

I see, my scenario is somewhat more complicated, than I wrote in my
initial posting. The point is, that I want to pass an object and a
method.

Something like this:

def executer(obj, method)
f.method(1)
end

class x
def test(x)
p x
end
end

o = x.new
executer(o, test)
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