How to call class methods which are stored in a variable

Question

If I want to call a class method (mailer method in rails), providing its name in a variable. How can I do that? For objects, we can use send, or we can use read_attribute to read some values

my_object.send("#{self.action_type(self)}")
my_object.read_attribute("#{self.action_type}_email")

But for class names, nothing is working as send is defined as instance method in object class. I want something like this, which will not work as send can't be applied on class:

Notifier.send("#{self.action_type(self)}").deliver

score 3 · Answer 1 · edited Mar 05 '13 at 13:04

3

Use eval

eval("Notifier.#{self.action_type}(self).deliver")

Not safe but it should work.

edited Mar 05 '13 at 13:04

Mohit Jain

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answered Mar 05 '13 at 12:57

Matzi

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Answers needs a minor fix and then it worked.. Made that modification in answer. Thanks a lot. – Mohit Jain Mar 05 '13 at 13:04

Mike Campbell · Answer 2 · 2013-03-05T22:37:39.697

2

You can also do:

method = Notifier.method(action_type)
method.call(self).deliver

edited Mar 05 '13 at 22:37

answered Mar 05 '13 at 13:04

Mike Campbell

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score 2 · Accepted Answer · answered Mar 05 '13 at 13:14

2

Classes are objects. There is no difference in how you apply send.

Notifier.send(action_type, self).deliver

answered Mar 05 '13 at 13:14

sawa

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Perfect.. :) Worked like charm – Mohit Jain Mar 05 '13 at 13:28
Doesn't this render this question completely worthless? Why did you say in your question that send didn't work on the Class? :/ – Mike Campbell Mar 05 '13 at 13:46
@MikeCampbell You don't need to blame the OP for the mistake. Coming to know that classes are objects, and therefore that `send` indeed works on them is a good achievement. – sawa Mar 05 '13 at 14:32
I'm not "blaming" the OP, I'm just questioning the value of a question where the accepted answer contradicts the premise of the question. – Mike Campbell Mar 05 '13 at 14:33

score 0 · Answer 4 · answered Mar 05 '13 at 13:08

0

you can also use

self.class.send(:your_class_method)

answered Mar 05 '13 at 13:08

AnkitG

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How to call class methods which are stored in a variable

4 Answers4