Given a string find the matching class

ruby-talk
1

I have a situation where I desire to pass a string to a method that
then:

1. Capitalizes the the string value

2. Finds a class by that name

Something like:

def findmyclass(m)
  find_class_by_name(m.capitalize)
end

Is this possible (surely) and if so, how is it done?

Thanks

···

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2

I have a situation where I desire to pass a string to a method that
then:
1. Capitalizes the the string value
2. Finds a class by that name
Something like:
def findmyclass(m)
find_class_by_name(m.capitalize)
end
Is this possible (surely) and if so, how is it done?

1 class names are constants, thus
    1.1 they start w upcase, and
    1.2 are case sensitive

2 you get the value of a quoted/stringified constant
    by using const_get

3 you can then check the value returned by checking if it #is_a? Class

eg,

Object.const_get("XX").is_a? Class

=> true

Object.const_get("Xx").is_a? Class

=> true

Object.const_get("YY")

NameError: uninitialized constant YY

now, if you want to find classes tucked in on other modules/classes,
you'll have to scan the whole ObjectSpace; eg, looking for a class
named "C" wc is in "A::b::C"...

eg,

ObjectSpace.each_object(Class).each {|x| p x if x.name =~ /^M/ }

Method
MatchData
Module
M::MM

···

On Wed, Dec 10, 2008 at 6:06 AM, James Byrne <byrnejb@harte-lyne.ca> wrote:

3

botp wrote:

3 you can then check the value returned by checking if it #is_a? Class

...

Object.const_get("XX").is_a? Class

=> true

Object.const_get("Xx").is_a? Class

=> true

Object.const_get("YY")

NameError: uninitialized constant YY

now, if you want to find classes tucked in on other modules/classes,
you'll have to scan the whole ObjectSpace; eg, looking for a class
named "C" wc is in "A::b::C"...

...

ObjectSpace.each_object(Class).each {|x| p x if x.name =~ /^M/ }
Method
MatchData
Module
M::MM

Many thanks for this lucid explanation.

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