Instance Variable On-Change

[Ryan Lewis]

I need to make a way to run a method when class' instance variable
changes from false to true and only run it once. But I have no idea how
to do this.

Any ideas?

 

[Tim Hunter]

I need to make a way to run a method when class' instance variable
changes from false to true and only run it once. But I have no idea how
to do this.

Any ideas?

Check out the observer library.

 

[Philipp Hofmann]

Check out the observer library.

why bother with observer if this can be nicely achieved with an
appropriate setter? something like ...

class SomeClass

def initialize
@switch = false
end

def switch=(value)
on_switch_becomes_true if !@switch && (@switch = value)
end

def on_switch_becomes_true
# ...
end

end

g phil

 

[Tim Hunter]

why bother with observer if this can be nicely achieved with an
appropriate setter? something like ...

Good catch! I confess I assumed that the OP would not have asked if a
plain setter method would do the trick.