Oct  4 08:44 2013 complexRectangularRep.lua Page 1


--[[ Complex Number Rectangular Representation Module
     H. Conrad Cunningham, Professor
     Computer and Information Science
     University of Mississippi

Developed for CSci 658, Software Language Engineering, Fall 2013

1234567890123456789012345678901234567890123456789012345678901234567890

2013-09-22: Separated Rectangular Representation Module

This module represents complex numbers with rectangular coordinates
stored in record-style tables.

--]]

-- Load complex number utilities module
local util = require "complexUtilities"

-- local definitions for convenience
local square    = util.square
local show_data = util.show_data


-- SCIP Section 2.4.1: Representations for Complex Numbers

-- Rectangular representation (character Ben in SICP)
-- Uses table { real = real_part, imag = imag_part }

local RECTANGULAR = "Rectangular"

local function real_part(z) return z.real end
local function imag_part(z) return z.imag end

local function magnitude(z)
  return math.sqrt(square(real_part(z)) + square(imag_part(z)))
end

local function angle(z)
  return math.atan2(imag_part(z), real_part(z))
end

local function make_from_real_imag(x,y) 
  return { real = x, imag = y }
end

local function make_from_mag_ang(r,a) 
  return { real = r * math.cos(a), imag = r * math.sin(a) }
end

-- Added function: Convert representation to string
local function to_string(z)
  return RECTANGULAR .. "(" .. tostring(real_part(z)) .. ", " 







Oct  4 08:44 2013 complexRectangularRep.lua Page 2


                            .. tostring(imag_part(z)) .. ")"
end


-- Module Export

return {
    make_from_real_imag = make_from_real_imag,
    make_from_mag_ang   = make_from_mag_ang,
    real_part           = real_part,
    imag_part           = imag_part,
    magnitude           = magnitude,
    angle               = angle,
    to_string           = to_string
  }