Class: EPNode

Inherits:
Array
  • Object
show all
Defined in:
lib/expressionparser.rb

Overview

SimpleExpression library Copyright © 2007 Noah Gibbs

This library is in the public domain, and may be redistributed in any way.

Instance Method Summary collapse

Instance Method Details

#eval(vars = {}) ⇒ Object 



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# File 'lib/expressionparser.rb', line 27

def eval(vars = {})
  args = self[1..-1].collect { |arg| EPNode.prveval(arg, vars) }
  op = self[0]

  op = "**" if op == "^"  # exponentiation uses different op in ruby

  if SimpleExpression.operator?(op)
    if self.length == 2
      return (op == "-" ? -args[0] : args[0])
    elsif self.length == 3
      return (args[0]).send(op, args[1])
    else
	raise "Unexpected number of arguments to #{op}!"
    end
  end

  if SimpleExpression.function?(op)
    return Math.send(op, args[0])
  end

  return vars[op] if vars[op] and self.length == 1

  raise "Unknown expression in EPNode##eval!"
end

#optimize(vars = {}) ⇒ Object

For now, just do constant folding



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# File 'lib/expressionparser.rb', line 53

def optimize(vars = {})
  args = self[1..-1].collect { |arg| EPNode.prveval(arg, vars, false) }
  if args.any? { |arg| arg == :NoInfo }
    opt = [ nil ] * args.length
    args.each_with_index do |arg, index|
	opt[index] = args[index]
	opt[index] = self[index + 1] if args[index] == :NoInfo
    end
    return EPNode.new(opt)
  end

  self.eval(vars)
end