Introduction

The COD program has been designed to fill two roles. First, it can be used like a programmable calculator. In this mode you can use the computer to do simple calculations (on days that your calculator is down). Second, it is designed to assist in developing and testing COD functions that can be used as components in PLT models.

This chapter will assume that you want to create a COD file that can be used with PLT. If you have no previous experience with COD, then you should start by running the COD program and learning how to use the stack and various built-in functions. (In COD, functions are sometimes called words.) Next you should create and use some simple colon definitions within COD itself. Colon definitions are the way one creates new functions. COD files contain ASCII text in the same form as you would type in interactive mode. A file that can be used as a model component by PLT is nothing more than a COD file containing a colon definition and supporting code. The COD program provides tools for the reading and testing of functions contained in COD files.