it wasn’t the if-

04/10/23 www.vsmerlot.com 1

The Model is the Code

Using COSA Technology

by

Gordon Morrison

Copyright © 2012

All Rights Reserved


It wasn’t the “go to”

• The ‘if’ has caused more spaghetti code than the ‘go to’ ever could.


Simple Calculator Example

• Subtract two negative numbers resulting in a negative result.


A COSA Solution

• Rules– Operand1– Operate– Operand2– Result– Done– Error


The Application

• Five Functions– Add– Subtract– Multiply– Divide– Percent

• Clear• Clear Entry


On Subtract Event

• Handled as Negate


Run Engine


Engine On


Check Event State

• Static State– Compared to

• Dynamic State


True Rule or Behavior

• Dynamically bind to True Member


Operand1 Rule

• Step– Negate


Rule’s True Behavior


Single Point True Trace


Trace what you want

• Complex or• Simple


Next Rule

• Base on True


Engine Off

• Return to OS…


Exit to OS


Model

• Model = Code• Code = Model


Application


Next On Click Event


Back to Engine


Same Rule Next Step

• Previous Step Allows– True Any Number– False One Period


True Behavior


Turn Engine Off


Trace


Next True Step


Engine Off


Return to OS


Rule Operand1 Step Any Number

• Model = Code• Code = Model


Number


Now Click Subtract


Subtract

• On Click Event


Not Any Number

• Next Step


Not Clear Entry


Not Clear


Rule Operate

• Not Step Addition


Not Addition Step

• Rule Operate


Rule Operate

• Step Subtract


Rule Operate

• Step Subtraction


Next Rule

• Operand 2


First Step

• Return to OS


Subtracting


Rule Operand2

• Step Negate


A Negative Number


Then Click Equals


On Click Equals


Not Any Number Step


Exit Rule Operand 2


Not Clear Entry

• Etc.


Result Rule

• Not Percent Step


Result Rule

• Equals Step


Result