Verify if a class exists


B

Bernd

Hello everybody,

is there a way to check, if a class exists? I create classes dynamically
and would like to know before, if a class with that name already exists.

Thanks for your help
Bernd
 
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S

Simen Edvardsen

Hello everybody,

is there a way to check, if a class exists? I create classes dynamically
and would like to know before, if a class with that name already exists.

Thanks for your help
Bernd

Try a const_get. Like so:

def class_exists?(name)
begin
true if Kernel.const_get(name)
rescue NameError
false
end
end
 
B

Bernd Burnt

Simen said:
Try a const_get. Like so:

def class_exists?(name)
begin
true if Kernel.const_get(name)
rescue NameError
false
end
end

Hi,
first of all, thanks for your help, Simen. I think, I even found a
better solution, I assign the name to the class with

Object.const_set class_name, klass

So I can determine, whether the class exists with

Object const_defined? class_name

You are using exception handling (rescue) for a conditional branch,
which I try to avoid whenever possible, to keep my code well structured.
 
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S

Simen Edvardsen

Hi,
first of all, thanks for your help, Simen. I think, I even found a
better solution, I assign the name to the class with

Object.const_set class_name, klass

So I can determine, whether the class exists with

Object const_defined? class_name

You are using exception handling (rescue) for a conditional branch,
which I try to avoid whenever possible, to keep my code well structured.

There is a const_defined? method? Ah, I see it's been some time since
I programmed Ruby. Excuse my ignorant advice, it seems you find a
better solution :)
 

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