Transformation of Applicative Specifications into Imperative ...

Hidden Observer
3.2. TERMS AND DEFINITIONS
A function observing the type T is named a hidden observer if T is not part
of the left hand side of the function signature, see Example 3.3.
Example 3.3 – Hidden observer
type
T = Int
value
hidden_obs : Int → Int
hidden_obs(x) ≡ obs(x),
obs : T → Int
obs(t) ≡ t
Hidden Generator
A generator altering values of the type T is named a hidden generator if T
is not part of the right hand side of the function signature, see Example 3.4.
Example 3.4 – Hidden generator
type
T = Int
value
hidden_gen : Int → Int
hidden_gen(x) ≡ gen(x),
gen : Int → T
gen(i) ≡ i
Implicit Observer
An implicit observer is a function which implicitly converts a value of a type
of interest into one of the equivalent type expressions during the evaluation
of the function body, see Example 3.5.
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