The document describes a calculator application built using COSA technology. COSA uses rules and states to model applications as code. The calculator application contains rules for operands, operations, results and other states. It can subtract two negative numbers and produce a negative result by treating subtraction as negation. The application and its rules are then stepped through as an example of using COSA to build applications where the model and code are the same.

1. The Model is the Code
Using COSA Technology
by
Gordon Morrison
Copyright © 2012
All Rights Reserved
05/08/12 www.vsmerlot.com 1

2. It wasn’t the “go to”
• The ‘if’ has caused
more spaghetti code
than the ‘go to’ ever
could.
05/08/12 www.vsmerlot.com 2

3. Simple Calculator Example
• Subtract two negative
numbers resulting in a
negative result.
05/08/12 www.vsmerlot.com 3

4. A COSA Solution
• Rules
– Operand1
– Operate
– Operand2
– Result
– Done
– Error
05/08/12 www.vsmerlot.com 4

5. The Application
• Five Functions
– Add
– Subtract
– Multiply
– Divide
– Percent
• Clear
• Clear Entry
05/08/12 www.vsmerlot.com 5

6. On Subtract Event
• Handled as Negate
05/08/12 www.vsmerlot.com 6

7. Run Engine
05/08/12 www.vsmerlot.com 7

8. Engine On
05/08/12 www.vsmerlot.com 8

9. Check Event State
• Static State
– Compared to
• Dynamic State
05/08/12 www.vsmerlot.com 9

10. True Rule or Behavior
• Dynamically bind to
True Member
05/08/12 www.vsmerlot.com 10

11. Operand1 Rule
• Step
– Negate
05/08/12 www.vsmerlot.com 11

12. Rule’s True Behavior
05/08/12 www.vsmerlot.com 12

13. Single Point True Trace
05/08/12 www.vsmerlot.com 13

14. Trace what you want
• Complex or
• Simple
05/08/12 www.vsmerlot.com 14

15. Next Rule
• Base on True
05/08/12 www.vsmerlot.com 15

16. Engine Off
• Return to OS…
05/08/12 www.vsmerlot.com 16

17. Exit to OS
05/08/12 www.vsmerlot.com 17

18. Model
• Model = Code
• Code = Model
05/08/12 www.vsmerlot.com 18

19. Application
05/08/12 www.vsmerlot.com 19

20. Next On Click Event
05/08/12 www.vsmerlot.com 20

21. Back to Engine
05/08/12 www.vsmerlot.com 21

22. 05/08/12 www.vsmerlot.com 22

23. 05/08/12 www.vsmerlot.com 23

24. Same Rule Next Step
• Previous Step Allows
– True Any Number
– False One Period
05/08/12 www.vsmerlot.com 24

25. True Behavior
05/08/12 www.vsmerlot.com 25

26. Turn Engine Off
05/08/12 www.vsmerlot.com 26

27. Trace
05/08/12 www.vsmerlot.com 27

28. Next True Step
05/08/12 www.vsmerlot.com 28

29. Engine Off
05/08/12 www.vsmerlot.com 29

30. Return to OS
05/08/12 www.vsmerlot.com 30

31. Rule Operand1 Step Any Number
• Model = Code
• Code = Model
05/08/12 www.vsmerlot.com 31

32. 05/08/12 www.vsmerlot.com 32

33. 05/08/12 www.vsmerlot.com 33

34. 05/08/12 www.vsmerlot.com 34

35. 05/08/12 www.vsmerlot.com 35

36. 05/08/12 www.vsmerlot.com 36

37. 05/08/12 www.vsmerlot.com 37

38. 05/08/12 www.vsmerlot.com 38

39. 05/08/12 www.vsmerlot.com 39

40. 05/08/12 www.vsmerlot.com 40

41. 05/08/12 www.vsmerlot.com 41

42. 05/08/12 www.vsmerlot.com 42

43. 05/08/12 www.vsmerlot.com 43

44. 05/08/12 www.vsmerlot.com 44

45. 05/08/12 www.vsmerlot.com 45

46. 05/08/12 www.vsmerlot.com 46

47. 05/08/12 www.vsmerlot.com 47

48. 05/08/12 www.vsmerlot.com 48

49. 05/08/12 www.vsmerlot.com 49

50. 05/08/12 www.vsmerlot.com 50

51. Number
05/08/12 www.vsmerlot.com 51

52. 05/08/12 www.vsmerlot.com 52

53. Now Click Subtract
05/08/12 www.vsmerlot.com 53

54. Subtract
• On Click Event
05/08/12 www.vsmerlot.com 54

55. Not Any Number
• Next Step
05/08/12 www.vsmerlot.com 55

56. Not Any Number
• Next Step
05/08/12 www.vsmerlot.com 56

57. Not Clear Entry
05/08/12 www.vsmerlot.com 57

58. Not Clear Entry
05/08/12 www.vsmerlot.com 58

59. Not Clear
05/08/12 www.vsmerlot.com 59

60. Not Clear
05/08/12 www.vsmerlot.com 60

61. Rule Operate
• Not Step Addition
05/08/12 www.vsmerlot.com 61

62. Not Addition Step
• Rule Operate
05/08/12 www.vsmerlot.com 62

63. Rule Operate
• Step Subtract
05/08/12 www.vsmerlot.com 63

64. Rule Operate
• Step Subtraction
05/08/12 www.vsmerlot.com 64

65. Next Rule
• Operand 2
05/08/12 www.vsmerlot.com 65

66. First Step
• Return to OS
05/08/12 www.vsmerlot.com 66

67. Subtracting
05/08/12 www.vsmerlot.com 67

68. 05/08/12 www.vsmerlot.com 68

69. 05/08/12 www.vsmerlot.com 69

70. Rule Operand2
• Step Negate
05/08/12 www.vsmerlot.com 70

71. 05/08/12 www.vsmerlot.com 71

72. 05/08/12 www.vsmerlot.com 72

73. 05/08/12 www.vsmerlot.com 73

74. A Negative Number
05/08/12 www.vsmerlot.com 74

75. 05/08/12 www.vsmerlot.com 75

76. 05/08/12 www.vsmerlot.com 76

77. 05/08/12 www.vsmerlot.com 77

78. 05/08/12 www.vsmerlot.com 78

79. 05/08/12 www.vsmerlot.com 79

80. 05/08/12 www.vsmerlot.com 80

81. 05/08/12 www.vsmerlot.com 81

82. 05/08/12 www.vsmerlot.com 82

83. 05/08/12 www.vsmerlot.com 83

84. 05/08/12 www.vsmerlot.com 84

85. 05/08/12 www.vsmerlot.com 85

86. 05/08/12 www.vsmerlot.com 86

87. 05/08/12 www.vsmerlot.com 87

88. 05/08/12 www.vsmerlot.com 88

89. 05/08/12 www.vsmerlot.com 89

90. Then Click Equals
05/08/12 www.vsmerlot.com 90

91. On Click Equals
05/08/12 www.vsmerlot.com 91

92. Not Any Number Step
05/08/12 www.vsmerlot.com 92

93. Exit Rule Operand 2
05/08/12 www.vsmerlot.com 93

94. 05/08/12 www.vsmerlot.com 94

95. Not Clear Entry
• Etc.
05/08/12 www.vsmerlot.com 95

96. Result Rule
• Not Percent Step
05/08/12 www.vsmerlot.com 96

97. Result Rule
• Equals Step
05/08/12 www.vsmerlot.com 97

98. Result
05/08/12 www.vsmerlot.com 98