From: 7stud -- <bbxx789_05ss@...>
Date: 2009-08-25T17:32:30+09:00
Subject: Re: operators vs. methods

Sarah Allen wrote:
> 7stud -- wrote:
>> Ruby gives you a choice with some methods, like +() and =(), to use a 
>> special syntax.  Special syntaxes are commonly known as "syntactic 
>> sugar".   What happens is that the "sugared syntax" is converted into 
>> the normal method call, so:
>> 
>> 1 + 2  becomes 1.+(2)
>> 
>> and
>> 
>> obj.x = 10 becomes obj.x=(10)  (where the method name is 'x=')
> 
> So, where might I find a list of the special sugary methods? 

I don't know.

> and may I 
> define my own?  

Not that I'm aware of.  However, you can define your own parser to 
replace the sugared syntax with a method call:

r3test.rb
------
class Apple
  def shout(str)
    puts "#{str.upcase}!!!"
  end
end

a = Apple.new
a shout "hello"  #<---'SUGARED' METHOD CALL
-----


----
class MyRubyParser
  attr_reader :data, :results

  def initialize(fname)
    @data = File.open(fname).readlines
    @results = []
  end

  def desugar(meth_name)
    @data.each do |line|
      line = line.chomp
      result = line.gsub(/^(.+?) (#{meth_name}) (.+)$/, '\1.\2(\3)' )
      results << result
    end
  end
end

parser = MyRubyParser.new("r3test.rb")
parser.desugar("shout")

program = parser.results.join("\n")
eval(program)

--output:--
HELLO!!!

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