Transformation of Applicative Specifications into Imperative ...

6.4. TRANSFORMING EXPLICIT FUNCTION DEFINITIONS
id : type_exprarg → type_exprres
id(id1, ..., idn) ≡ value_expr
the variable has to be assigned the proper value. There are two cases to
consider. The type expression type_exprres of the result of the function is:
1. T.
Transformation: The variable must be assigned the transformed
value_expr, see function gen1 in Example 6.12.
2. a product in which T occurs.
Transformation: The variable must be assigned the proper part of
the product expression of value_expr, see function gen2 in Example
6.12.
Example 6.12 – Assignment expressions in generators
type
T = Int
value
gen1 : Int → T
gen1(i) ≡ i,
✄
gen2 : Int × Bool → T × Bool
gen2(i, b) ≡ (i, b)
type
T = Int
variable
t : T
value
gen1 : Int → write t Unit
gen1(i) ≡ t := i,
gen2 : Int × Bool → write t Bool
gen2(i, b) ≡
let (pa_0, pa_1) = (t := i, b) in (pa_1) end
When dealing with implicit generators, that is when a value of the type
of interest is expected, assignment expressions have to be established. This
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