From: Andreas Lundgren <andreas.lundgren.x@...>
Date: 2011-05-18T22:46:02+09:00
Subject: Generating Functions in Ruby

Hi!

I'm looking for a construction in Ruby to generate a (big) set of
functions. I need these functions to be class methods and called by
unique names since they are called via an external API.

As an example, let me create two functions that hard codes an addition
and then uses this in a small test program.

def FivePlusFour
  return 5+4
end

def OnePlusSeven
  return 1+7
end

puts("Five + Four is " + FivePlusFour().to_s)
puts("One + Seven is " + OnePlusSeven().to_s)


I would like a way to generate the methods in runtime. As an old C-
programmer, I'm looking for something like this:

# Define a macro
define SUM_TEMPLATE(namn,x,y) \\
def namn \\
  return x+y \\
end

# Create each function with a one-liner in runtime.
SUM_TEMPLATE(FivePlusFour, 5, 4)
SUM_TEMPLATE(OnePlusSeven, 1, 7)

# Test program
puts("Five + Four is " + FivePlusFour().to_s)
puts("One + Seven is " + OnePlusSeven().to_s)

Is this possible in Ruby?

(Please don't reply how to solve this silly example in a better way,
the true use case is of cause much more complex. But conceptually it's
the same.)

Best Regards,
Andreas Lundgren - Sweden