1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
|
-- This package defines the notion of a token. In general terms a token is
-- the smallest lexical entity known to SDC.
with Instructions;
with Values;
with Values.Operations;
package Tokens is
type Token_Kind is (Val, Op, Instr);
type Token (Kind : Token_Kind) is private;
-- The actual token type.
function Next return Token;
-- Reads the input characters typed by the user
-- and converts them into tokens.
procedure Process (T : Token);
-- Process token T, ie undertake the actions corresponding to token T.
private
type Token (Kind : Token_Kind) is record
case Kind is
when Val =>
Val : Values.Value;
when Op =>
Op : Values.Operations.Operation;
when Instr =>
Instr : Instructions.Instruction;
end case;
end record;
end Tokens;
|
