Transformation of Applicative Specifications into Imperative ...

CHAPTER 9. IMPLEMENTATION OF THE TRANSFORMER
1
RSLAstVisitor
+visitValueInfixExpr(ind valueInfixExpr : ValueInfixExpr)
+visitPLUS(ind plus : PLUS)
+visitValueInfixExpr(ind valueInfixExpr : ValueInfixExpr)
+visitPLUS(ind plus : PLUS)
ValueInfixExpr
+accept(ind visitor : RSLAstVisitor)
*
StringRSLAstVisitor
RSLElement
+accept(ind visitor : RSLAstVisitor)
PLUS
+accept(ind visitor : RSLAstVisitor)
Figure 9.6: The use of the visitor design pattern in the transformer
Example 9.2 – Code snippet of the StringRSLAstVisitor.java
public void v i s i t V a l u e I n f i x E x p r ( ValueInfixExpr v a l u e I n f i x E x p r ) {
v a l u e I n f i x E x p r . l e f t ( ) . accept ( this ) ;
r e s u l t . append ( " " ) ;
v a l u e I n f i x E x p r . op ( ) . accept ( this ) ;
r e s u l t . append ( " " ) ;
v a l u e I n f i x E x p r . r i g h t ( ) . accept ( this ) ;
}
public void v i s i t L e t E x p r ( LetExpr letExpr ) {
r e s u l t . append ( " l e t " ) ;
for ( LetDef l e t D e f : letExpr . l e t _ d e f _ l i s t ( ) . g e t L i s t ( ) ) {
l e t D e f . accept ( this ) ;
r e s u l t . append ( " , " ) ;
}
i f ( letExpr . l e t _ d e f _ l i s t ( ) . l e n ( ) > 0) {
r e s u l t . d e l e t e ( r e s u l t . l ength ( ) − 2 , r e s u l t . length ( ) ) ;
}
r e s u l t . append ( " in " ) ;
letExpr . let_value_expr ( ) . accept ( this ) ;
104