Try Catch With Ruby Blocks

'RenameMe to ContinuationsInRuby ?'

People on BlocksInPython want to see TryCatch implemented in RubyLanguage. I won't dive in a SchemeLanguage-like continuation-based ErrorHandling, just note that this (somewhat) already exists:


        def routine(n)

        puts n

        throw :done if n <= 0

        routine(n-1)

        end


        catch(:done) do

        routine(3)

        end

RubyLanguage's 'throw' and 'catch' is GoTo. GoTo has its uses, but for conventional ErrorHandling use 'raise' and 'rescue':


        def factorial(n)

        raise ArgumentError, "factorial arg must be >= 0: #{n}" unless n >= 0

        return 1 if n.zero?

        (1..n).inject(1) { |product, i| product * i }

        end


        while true

        print 'Enter a number (-1 to quit): '

        n = gets.to_i

        exit if n == -1

        begin

        puts "#{n}! = #{factorial(n)}"

        rescue ArgumentError => e

        puts e

        end

        end

CategoryRuby