class Uniquify
# Return a version of the given 'base' string that is unique
# by appending a counter to it. Uniqueness is determined by
# repeated calls to the passed block.
#
# If `base` is a function/proc, we expect that calling it with a
# candidate counter returns a string to test/return.
def string(base)
@base = base
@counter = nil
increment_counter! while yield(base_string)
base_string
end
private
def base_string
if @base.respond_to?(:call)
@base.call(@counter)
else
"#{@base}#{@counter}"
end
end
def increment_counter!
@counter ||= 0
@counter += 1
end
end