Transformation of Applicative Specifications into Imperative ...

CHAPTER 8. SPECIFICATIONS
The rewriting of the specification from RSL to RSL1 requires some changes.
The correctness of these changes is discussed in Section 8.5.
8.2 Specification of the RSL AST
The specification of the RSL AST RSLAst_Module2.rsl, which can be found
in Appendix D, is written in RSL1, such that the specification can be transformed
into Java using the RSL2Java tool and thereby be used as part of
the transformer.
The specification of the RSL AST consists purely of type definitions
that are either variant definitions or short record definitions. These type
definitions describe the structure of an RSL AST. The specification of the
RSL AST is based on the concrete syntax summary of RSL offered in [Gro92,
pp. 371-380] and the changes to RSL which can be found in [Gro95]. The
construction of the RSL AST is straight forward when following these syntax
summaries.
In RSL graphical symbols like parenthesizes and commas are used to
distinguish between the different kinds of RSL constructs. When the type
of an RSL construct is determined these symbols are superfluous and can be
discarded. This is exploited in the specification of the RSL AST where only
the necessary information is kept.
Otherwise the syntax of RSL consists of terminals T and nonterminals
NT. Terminals are indivisible entities, whereas nonterminals are symbols
that can be expressed in terms of other symbols, terminals or nonterminals.
The relationship between the RSL syntax and the RSL AST specification
is described in the following.
Syntax of the form
becomes
whereas
becomes
NT ::= NT1 . . . NTn
NT :: nt1 : NT1 . . . ntn : NTn
NT ::= NT1| . . . |NTn
NT1 ::= NT11 . . . NT1n
.
NTn ::= NTn1 . . . NTnn
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