1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
10 -- Copyright (C) 1996-2001 Free Software Foundation, Inc. --
12 -- GNAT is free software; you can redistribute it and/or modify it under --
13 -- terms of the GNU General Public License as published by the Free Soft- --
14 -- ware Foundation; either version 2, or (at your option) any later ver- --
15 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
16 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
17 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
18 -- for more details. You should have received a copy of the GNU General --
19 -- Public License distributed with GNAT; see file COPYING. If not, write --
20 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
21 -- MA 02111-1307, USA. --
23 -- GNAT was originally developed by the GNAT team at New York University. --
24 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
26 ------------------------------------------------------------------------------
28 with Types
; use Types
;
30 -- Package containing all the routines to process a list of discrete choices.
31 -- Such lists can occur in 3 different constructs: case statements, array
32 -- aggregates and record variants. We have factorized what used to be 3 very
33 -- similar sets of routines here. If you didn't figure it out already Choi
34 -- in the package name stands for Choices.
38 type Choice_Bounds
is record
44 type Choice_Table_Type
is array (Pos
range <>) of Choice_Bounds
;
45 -- Table type used to sort the choices present in a case statement,
46 -- array aggregate or record variant.
48 procedure No_OP
(C
: Node_Id
);
49 -- The no-operation routine. Does absolutely nothing. Can be used
50 -- in the following generic for the parameter Process_Empty_Choice.
53 with function Get_Alternatives
(N
: Node_Id
) return List_Id
;
54 -- Function needed to get to the actual list of case statement
55 -- alternatives, or array aggregate component associations or
56 -- record variants from which we can then access the actual lists
57 -- of discrete choices. N is the node for the original construct
58 -- ie a case statement, an array aggregate or a record variant.
60 with function Get_Choices
(A
: Node_Id
) return List_Id
;
61 -- Given a case statement alternative, array aggregate component
62 -- association or record variant A we need different access functions
63 -- to get to the actual list of discrete choices.
65 with procedure Process_Empty_Choice
(Choice
: Node_Id
);
66 -- Processing to carry out for an empty Choice.
68 with procedure Process_Non_Static_Choice
(Choice
: Node_Id
);
69 -- Processing to carry out for a non static Choice.
71 with procedure Process_Associated_Node
(A
: Node_Id
);
72 -- Associated to each case alternative, aggregate component
73 -- association or record variant A there is a node or list of nodes
74 -- that need semantic processing. This routine implements that
77 package Generic_Choices_Processing
is
79 function Number_Of_Choices
(N
: Node_Id
) return Nat
;
80 -- Iterates through the choices of N, (N can be a case statement,
81 -- array aggregate or record variant), counting all the Choice nodes
82 -- except for the Others choice.
84 procedure Analyze_Choices
87 Choice_Table
: in out Choice_Table_Type
;
88 Last_Choice
: out Nat
;
89 Raises_CE
: out Boolean;
90 Others_Present
: out Boolean);
91 -- From a case statement, array aggregate or record variant N, this
92 -- routine analyzes the corresponding list of discrete choices.
93 -- Subtyp is the subtype of the discrete choices. The type against
94 -- which the discrete choices must be resolved is its base type.
96 -- On entry Choice_Table must be big enough to contain all the
97 -- discrete choices encountered.
99 -- On exit Choice_Table contains all the static and non empty
100 -- discrete choices in sorted order. Last_Choice gives the position
101 -- of the last valid choice in Choice_Table, Choice_Table'First
102 -- contains the first. We can have Last_Choice < Choice_Table'Last
103 -- for one (or several) of the following reasons:
105 -- (a) The list of choices contained a non static choice
107 -- (b) The list of choices contained an empty choice
108 -- (something like "1 .. 0 => ")
110 -- (c) One of the bounds of a discrete choice contains an
111 -- error or raises constraint error.
113 -- In one of the bounds of a discrete choice raises a constraint
114 -- error the flag Raise_CE is set.
116 -- Finally Others_Present is set to True if an Others choice is
117 -- present in the list of choices.
119 end Generic_Choices_Processing
;