Created
November 27, 2010 14:40
-
-
Save alexmacedo/717937 to your computer and use it in GitHub Desktop.
lazy proc implementation in ruby
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| module Lazy | |
| class LazyProc | |
| alias __class__ class | |
| instance_methods.each { |m| undef_method m unless m =~ /^__/ or m == :object_id } | |
| def initialize(&computation) | |
| @computation = computation | |
| end | |
| def inspect | |
| if @value | |
| @value.inspect | |
| else | |
| "#<#{__class__} computation=#{@computation.inspect}>" | |
| end | |
| end | |
| def respond_to?(method) | |
| method = method.to_sym | |
| method == :inspect or | |
| method == :evaluate or | |
| evaluate.respond_to?(method) | |
| end | |
| def method_missing(method, *args, &block) | |
| evaluate.__send__(method, *args, &block) | |
| end | |
| def evaluate | |
| @value = @computation.call unless @value | |
| @value | |
| end | |
| end | |
| class LispyEnumerable | |
| include Enumerable | |
| def initialize(list) | |
| @list = list | |
| end | |
| def each | |
| while @list | |
| car,cdr = @list | |
| yield car | |
| @list = cdr | |
| end | |
| end | |
| end | |
| end # module | |
| module Kernel | |
| def lazy(&block) | |
| Lazy::LazyProc.new(&block) | |
| end | |
| end |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment