Attempt to use ruby to generate some functional constructs.

README.rdoc

Functional¶ ↑

• Functional

DESCRIPTION:¶ ↑

Using Ruby to generate some functional constructs

FEATURES/PROBLEMS:¶ ↑

Uses dynamic memoization for performance

PROBLEMS:¶ ↑

None currently know.

EXAMPLES:¶ ↑

See Example.rb

REQUIREMENTS:¶ ↑

• None

INSTALL:¶ ↑

• gem

LICENSE:¶ ↑

(The MIT License)

Copyright © 2009 Frogstarr78 Software

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the ‘Software’), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED ‘AS IS’, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Benchmark.rb

require 'benchmark'
require 'Functional'

Benchmark.bmbm 30 do |bm|
  f = Functional.new
  bm.report( "define fib 1" ) { f.define( :fib, 1 ) { 1 } }
  bm.report( "define fib 2" ) { f.define( :fib, 2 ) { 1 } }
  bm.report( "define fib Fixnum" ) { f.define( :fib, Fixnum ) {|n| fib(n-1) + fib(n-2) } }


  bm.report("1 call f.fib 1") { puts f.fib 1 }
  bm.report("1 call f.fib 2") { puts f.fib 2 }
  bm.report("1 call f.fib 4") { puts f.fib 4 }
  bm.report("1 call f.fib 14") { puts f.fib 14 }

  bm.report("2 call f.fib 1") { puts f.fib 1 }
  bm.report("2 call f.fib 2") { puts f.fib 2 }
  bm.report("2 call f.fib 4") { puts f.fib 4 }
  bm.report("2 call f.fib 14") { puts f.fib 14 }
#  bm.report("call f.fib 1014") { puts f.fib 1014 }
end

puts '','='*100,''

class Fib
  def self.run n
    case n
    when 1, 2
      1
    else
      run(n-1) + run(n-2)
    end
  end
end

Benchmark.bmbm 30 do |bm|
#  bm.report( "define class Fib w/ case statement" ) { 
#  }

  bm.report("1 call f.fib 1 w/ case") { puts Fib.run 1 }
  bm.report("1 call f.fib 2 w/ case") { puts Fib.run 2 }
  bm.report("1 call f.fib 4 w/ case") { puts Fib.run 4 }
  bm.report("1 call f.fib 14 w/ case") { puts Fib.run 14 }

  bm.report("2 call f.fib 1 w/ case") { puts Fib.run 1 }
  bm.report("2 call f.fib 2 w/ case") { puts Fib.run 2 }
  bm.report("2 call f.fib 4 w/ case") { puts Fib.run 4 }
  bm.report("2 call f.fib 14 w/ case") { puts Fib.run 14 }
#  bm.report("call f.fib 1014") { puts Fib.run 1014 }
end

Example.rb

$LOAD_PATH.unshift '.' if RUBY_VERSION > '1.9.1'
require 'Functional'

def hr size
  puts '-' * size
end

hr 10
f = Functional.new
f.define( :fac, 0 ) { 1 }
f.define( :fac, Fixnum ) {|n| n * fac(n-1) }
puts f.fac 0
puts f.fac 4

hr 10
f.define( :fib, 1 ) { 1 }
f.define( :fib, 2 ) { 1 }
f.define( :fib, Fixnum ) {|n| fib(n-1) + fib(n-2) }

puts f.fib 1
puts f.fib 2
puts f.fib 12

Functional.rb

class Functional
  def define name, argument, &block 
    if not self.respond_to? name
      self.class.send :define_method, name do |arg|
        if self.respond_to? "#{name}_#{arg}"
          method_name = "#{name}_#{arg}"
          method(method_name).call arg
        else
          method_name = "#{name}_#{arg.class}"
          value = method(method_name).call arg
          define name, arg, &lambda { value }
          value
        end
      end
    end

    self.class.send :define_method, "#{name}_#{argument}", block
  end
end