Module: NamedArgs

Included in:
Class, Module
Defined in:
lib/arguments/class.rb

Instance Method Summary collapse

Instance Method Details

#named_arguments_for(*methods) ⇒ Object Also known as: named_args_for, named_args 



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# File 'lib/arguments/class.rb', line 2

def named_arguments_for *methods
  methods = instance_methods - Object.methods if methods.empty?
  
  methods.each do |meth|
    if(meth.to_s.include?('.'))
       # they may have passed in a parameter like :klass.method for a class method
       klass, meth = meth.to_s.split('.')
       klass = eval(klass) # from "Klass" to Klass
       klass = (class << klass; self; end)
       names = Arguments.names klass, meth
    else
      names  = Arguments.names self, meth
      klass = self
    end
    next if names.empty? || names.any?{|name| name[0] == :"*args"}
    
    assigns = []
    names.each_with_index do |name, index|
      unless name.size == 1
        # optionals
        assigns << <<-RUBY_EVAL
          #{ name.first } =
          if opts.key?(:#{ name.first })
            opts[:#{ name.first }]
          else
            args.size >= #{ index + 1 } ? args[#{ index }] : #{ name.last }
          end
        RUBY_EVAL
      else
        # requireds
        assigns << <<-RUBY_EVAL 
          begin
            #{ name.first } = opts.key?(:#{ name.first }) ? opts[:#{ name.first }] : args.fetch(#{ index })
          rescue 
            raise ArgumentError.new('passing `#{ name.first }` is required')
          end
        RUBY_EVAL
      end
    end

    line_loc = __LINE__
    new_code = <<-RUBY_EVAL
      def __new_#{ meth } *args, &block
        opts = args.last.kind_of?( Hash ) ? args.pop : {}
        #{ assigns.join("\n") }
        __original_#{ meth } #{ names.collect{ |n| n.first }.join(', ') }, &block
      end
      
      alias __original_#{ meth } #{ meth }
      alias #{ meth } __new_#{ meth }
    RUBY_EVAL

    begin
      klass.module_eval new_code, __FILE__, line_loc + 1
    rescue SyntaxError => e
        puts "warning--unable to wrap method #{ meth } -- possibly a syntax exception or it's not all on one line in 1.9 -- #{new_code}"
        throw e
    end
      
  end
end