1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
|
Syntax: bf(%polymorphic) tt(polymorphic-specification(s))
The tt(%polymorphic) directive is used to define a polymorphic semantic value
class, offering a (preferred) alternative to (traditional) tt(union) types.
Refer to section ref(POLYMORPHIC) for a detailed description of the
specification, characteristics, and use of polymorphic semantic values.
As a quick reference: to define multiple semantic values using a polymorphic
semantic value class offering either an tt(int), a tt(std::string) or a
tt(std::vector<double>) specify:
verb(
%polymorphic INT: int; STRING: std::string;
VECT: std::vector<double>
)
and use tt(%type) specifications (cf. section ref(TYPE)) to associate
(non-)terminals with specific semantic value types.
tt(%stype, %union) and tt(%polymorphic) are mutually exclusive: only one
of these directives can be used.
|
