Syntax-Directed Translation - Crafting a Compiler - page 266

class Visitor
/ Generic visit / 28

procedure visit (AbstractNode n )

n . accept( this )
end
end

29

class TypeChecking extends Visitor
procedure

30

visit ( IfNode i )

end
procedure

visit (PlusNode p )

end
procedure visit (MinusNode m )

end
end

class IfNode extends AbstractNode

procedure accept (Visitor v )

31

v . visit( this )
end
...
end
class PlusNode extends AbstractNode

procedure accept (Visitor v )

32

v . visit( this )
end
...
end
class MinusNode extends AbstractNode

33

procedure accept (Visitor v )

34

v . visit( this )
end
...
end

Figure 7.23: Visitor pattern