How can I make these methods better?
Range.class_eval do
def addto_begin(x)
return self.begin + x..self.end
end
def addto_end(x)
return self.begin..self.end+x
end
end
Right now, I have to type:
x = 1..10
x = x.addto_begin(3)
to change the begin of the range. What I want to be able to do is:
x = 1..10
x.addto_begin(3)
How do I do this?
Since ranges are immutable you would need to create your own range class that encapsulates the basic range object. This class will give you that and still keep and the methods associated with the basic range object.
class Myrange
attr_accessor :range
def initialize(a,b=nil,exc=false)
if a.is_a? Range
@range = a
else
@range = Range.new(a,b,exc)
end
end
def addto_begin(x)
Myrange.new(@range.begin + [email protected])
end
def addto_end(x)
Myrange.new(@[email protected]+x)
end
def addto_begin!(x)
@range = @range.begin + [email protected]
Myrange.new(@range)
end
def addto_end!(x)
@range = @[email protected]+x
Myrange.new(@range)
end
def to_s
@range.to_s
end
def inspect
self.to_s
end
def method_missing(*args,&blk)
@range.send(*args,&blk)
end
end
x = Myrange.new(1,10)
x = x.addto_begin(3)
p x #=> 4..10
y = x.addto_begin!(3)
p x #=> 7..10
p y.addto_end(3) #=> 7..13
p x.include? 9 #=> true :: Range methods still work
You can't. Range doesn't provide write access to properties (i.e. begin/end).
