ruby DSL example

dsl.rb

class DSL 

	def go (&block)
		instance_eval &block if block
		self
	end
	def self.go (&block)
		DSL.new.go(&block)		
	end
	def from (old_self,&block)
		@old_self = old_self
		instance_eval &block if block
		self
	end
	def method_missing(method,*args,&block)
		if @old_self then
			return @old_self.method(method).call(*args,&block)
		else
			raise NoMethodError.new "could not find #{method} on #{self} or #{@old_self}"
		end
	end
	def x message 
		puts "#{self.class}.X: #{message}"
	end
end

def x message
	puts "X: #{message}"
end
def y message
	puts "Y: #{message}"
end

x "outside dsl: #{self.class}"

DSL.go {
	x "inside dsl: #{self.class}"
	y "inside dsl: #{self.class}"
}

class Foo 
	def x message
		puts "Foo.X: #{message}"
	end
	def y message
		puts "Foo.Y: #{message}"
	end
	def z message
		puts "Foo.Z: #{message}"
	end

	def useDsl
		DSL.go.from(self) {
			x "class dsl #{self.class}"
			y "class dsl: #{self.class}"
			z "class dsl: #{self.class}"
		}
		begin
			DSL.go {
				z "class dsl: #{self.class}"
			}
		rescue Exception => e
			puts "	#{e.class} - #{e}"
		end
	end
end

Foo.new.useDsl

output of this gist here: run this gist

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