ruby/doc/rake/proto_rake.rdoc

= Original Prototype Rake

This is the original 100 line prototype rake program.

---
 #!/usr/bin/env ruby
 
 require 'ftools'
 
 class Task
   TASKS = Hash.new
 
   attr_reader :prerequisites
 
   def initialize(task_name)
     @name = task_name
     @prerequisites = []
     @actions = []
   end
 
   def enhance(deps=nil, &block)
     @prerequisites |= deps if deps
     @actions << block if block_given?
     self
   end
 
   def name
     @name.to_s
   end
 
   def invoke
     @prerequisites.each { |n| Task[n].invoke }
     execute if needed?
   end
 
   def execute
     return if @triggered
     @triggered = true
     @actions.collect { |act| result = act.call(self) }.last
   end
 
   def needed?
     true
   end
 
   def timestamp
     Time.now
   end
 
   class << self
     def [](task_name)
       TASKS[intern(task_name)] or fail "Don't know how to rake #{task_name}"
     end
     
     def define_task(args, &block)
       case args
       when Hash
 	fail "Too Many Target Names: #{args.keys.join(' ')}" if args.size > 1
 	fail "No Task Name Given" if args.size < 1
 	task_name = args.keys[0]
 	deps = args[task_name]
       else
 	task_name = args
 	deps = []
       end
       deps = deps.collect {|d| intern(d) }
       get(task_name).enhance(deps, &block)
     end
 
     def get(task_name)
       name = intern(task_name)
       TASKS[name] ||= self.new(name)
     end
 
     def intern(task_name)
       (Symbol === task_name) ? task_name : task_name.intern
     end
   end
 end
 
 class FileTask < Task
   def needed?
     return true unless File.exist?(name)
     latest_prereq = @prerequisites.collect{|n| Task[n].timestamp}.max
     return false if latest_prereq.nil?
     timestamp < latest_prereq
   end
 
   def timestamp
     File.new(name.to_s).mtime
   end
 end
 
 def task(args, &block)
   Task.define_task(args, &block)
 end
 
 def file(args, &block)
   FileTask.define_task(args, &block)
 end
 
 def sys(cmd)
   puts cmd
   system(cmd) or fail "Command Failed: [#{cmd}]"
 end
   
 def rake
   begin
     here = Dir.pwd
     while ! File.exist?("Rakefile")
       Dir.chdir("..")
       fail "No Rakefile found" if Dir.pwd == here
       here = Dir.pwd
     end
     puts "(in #{Dir.pwd})"
     load "./Rakefile"
     ARGV.push("default") if ARGV.size == 0
     ARGV.each { |task_name| Task[task_name].invoke }
   rescue Exception => ex
     puts "rake aborted ... #{ex.message}"
     puts ex.backtrace.find {|str| str =~ /Rakefile/ } || ""
   end    
 end
 
 if __FILE__ == $0 then
   rake
 end