private void define(String id, Type type, CommonTree decl) {
// Add id with its type to the type table, checking
// that id is not already declared in the same scope.
boolean ok = typeTable.put(id, type);
if (!ok) reportError(id + " is redeclared", decl);
}
private void predefine() {
// Add predefined procedures to the type table.
typeTable.put("read", new Type.Mapping(Type.VOID, Type.INT));
typeTable.put("write", new Type.Mapping(Type.INT, Type.VOID));
}