Transformation of Applicative Specifications into Imperative ...

6.4. TRANSFORMING EXPLICIT FUNCTION DEFINITIONS
the type T, the value of type T has to be converted into an Int. This is done
by an implicit observer.
In the imperative specification the T-generator gen does not return any
value, but a value is needed as first argument of the plus infix expression.
This is accomplished by establishing a sequencing expression (gen(x) ; t) in
order to extract the proper value to be used in the plus infix expression.
Example 6.14 – Establishing sequencing expressions
scheme A_SPEC =
class
type
T = Int
✄
end
value
implicit_obs : Int → Int
implicit_obs(x) ≡ gen(x) + x,
gen : Int → T
gen(x) ≡ x + 1
scheme I_SPEC =
class
type
T = Int
end
variable
t : T
value
implicit_obs : Int → read t write t Int
implicit_obs(x) ≡ (gen(x) ; t) + x,
gen : Int → write t Unit
gen(x) ≡ t := x + 1
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