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
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
|
with Except;
with Input; use Input;
with Stack;
package body Values is
-------------
-- Process --
-------------
procedure Process (V : Value) is
begin
Stack.Push (V);
end Process;
----------
-- Read --
----------
function Read (Word : String) return Value is
Int_Val : Integer;
Real_Val : Float;
Kind : Input.Number_Kind;
begin
Input.Read_Number (Word, Int_Val, Real_Val, Kind);
if Kind /= Int_Number then
raise Except.User_Error;
end if;
return new Value_Info'(E => Int_Val);
-- Allocate a new Value_Info (which is a record with one field)
-- on the heap and initialize its only field "E" to be "Int_Val".
-- NOTE: the ' in Value_Info'(...) must be there.
end Read;
---------------
-- To_String --
---------------
function To_String (V : Value) return String is
begin
return Integer'Image (V.E);
-- V is a pointer to a Value_Info record. V.all is the
-- actual Value_Info record pointed by V. Thus, strictly speaking,
-- we shoudl have written V.all.E above. However, Ada allows to
-- remove the ".all" because the meaning of expression "V.E" is
-- clear from its context.
end To_String;
end Values;
|
