Transformation of Applicative Specifications into Imperative ...

CHAPTER 2. GENERAL IDEA
value
increment : Unit → read t, s write t Unit
increment() ≡ t := t + s
end
The problem occurs because it is necessary to distinguish between the
type names of the types of interest and the actual types of the types of
interest. This means that the type inference of the value expressions changes
accordingly. A value expressions with type of interest T = type_expr is
treated as a value expression of type T and not of type type_expr as the
static inference of RSL normally prescribes. The type of a value expression
is solely determined based on the single typing of the function definition in
which the value expression is incorporated.
This makes new demands on the specification style. It is very important
that the types of interest are used with care in the applicative specification.
They shall only be used in contexts where they are actually wanted. When
it is necessary that only some occurrences of a type of interest should be
transformed as types of interest, it is necessary to establish other type names
with the same type as the type of interest. Then these new type names
should be used whenever an expression should not be transformed as a type
of interest.
The problem could be avoided by making an interactive transformer in
which the user interactively could decide which occurrences of the types of
interest that should be transformed as such and which should be transformed
as ordinary types. This solution is not implemented in this project.
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