On Sat, Sep 26, 2009 at 8:38 PM, Mario Gr <[email protected]> wrote: > Got it - maybe. I found a good resource[1], but I am not sure I > understand the value of the setter method in the first place. It would > seem that benefit is being able to skip explicitly calling save on an > object. Is that right?
The benefit of getter and setter methods are many - essentially they allow you to perform operations on the variable before and after they are retrieved or set. This is part of object-oriented methodology. But in reference to your first question - "I was wondering what methods ending in an equal sign meant", it is a feature of Ruby itself that methods can end in "!", "?" and "=", and the community has taken these to mean "potentially dangerous/exception creating", "interrogative (should return a boolean)" and "sets a variable", respectively. > If I had this method defined on my class: > > def my_attribute=(some_value) > �...@some_value = some_value > end > > I could call: > > �[email protected]_attribute = new_value > > instead of: > > �[email protected]_attribute = new_value > �[email protected] > > Is that the reason to define a setter method? No, because in #my_attribute=, you did not call save. Here is a reason to define a setter method: class Shape def save_intersection=(shape) @intersection = self.calculate_intersection(shape) end end That is, we need to calculate the intersection of these two shapes and then we can store the result in an instance variable. This is a good use of the setter syntax, because it sets a variable, and we need to do something "special". However, if we're not doing anything special with the variable being set, it is preferable to write: class Shape attr_accessor :points end Which automatically defines the methods #points, which gets the instance variable @points, and #points=, which will set the instance variable if you used it like: shape = Shape.new shape.points = [1.2, 3,3] Colin --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en -~----------~----~----~----~------~----~------~--~---
