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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S E M _ C A S E --
-- --
-- S p e c --
-- --
-- Copyright (C) 1996-2008, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING3. If not, go to --
-- http://www.gnu.org/licenses for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- Package containing the routines to process a list of discrete choices.
-- Such lists can occur in two different constructs: case statements and
-- record variants. We have factorized what used to be two very similar
-- sets of routines in one place. These are not currently used for the
-- aggregate case, since issues with nested aggregates make that case
-- substantially different.
with Types; use Types;
package Sem_Case is
type Choice_Bounds is record
Lo : Node_Id;
Hi : Node_Id;
Node : Node_Id;
end record;
type Choice_Table_Type is array (Pos range <>) of Choice_Bounds;
-- Table type used to sort the choices present in a case statement,
-- array aggregate or record variant.
procedure No_OP (C : Node_Id);
-- The no-operation routine. Does absolutely nothing. Can be used
-- in the following generic for the parameter Process_Empty_Choice.
generic
with function Get_Alternatives (N : Node_Id) return List_Id;
-- Function needed to get to the actual list of case statement
-- alternatives, or array aggregate component associations or
-- record variants from which we can then access the actual lists
-- of discrete choices. N is the node for the original construct
-- i.e. a case statement, an array aggregate or a record variant.
with function Get_Choices (A : Node_Id) return List_Id;
-- Given a case statement alternative, array aggregate component
-- association or record variant A we need different access functions
-- to get to the actual list of discrete choices.
with procedure Process_Empty_Choice (Choice : Node_Id);
-- Processing to carry out for an empty Choice
with procedure Process_Non_Static_Choice (Choice : Node_Id);
-- Processing to carry out for a non static Choice
with procedure Process_Associated_Node (A : Node_Id);
-- Associated to each case alternative, aggregate component
-- association or record variant A there is a node or list of nodes
-- that need semantic processing. This routine implements that
-- processing.
package Generic_Choices_Processing is
function Number_Of_Choices (N : Node_Id) return Nat;
-- Iterates through the choices of N, (N can be a case statement,
-- array aggregate or record variant), counting all the Choice nodes
-- except for the Others choice.
procedure Analyze_Choices
(N : Node_Id;
Subtyp : Entity_Id;
Choice_Table : out Choice_Table_Type;
Last_Choice : out Nat;
Raises_CE : out Boolean;
Others_Present : out Boolean);
-- From a case statement, array aggregate or record variant N, this
-- routine analyzes the corresponding list of discrete choices.
-- Subtyp is the subtype of the discrete choices. The type against
-- which the discrete choices must be resolved is its base type.
--
-- On entry Choice_Table must be big enough to contain all the discrete
-- choices encountered. The lower bound of Choice_Table must be one.
--
-- On exit Choice_Table contains all the static and non empty discrete
-- choices in sorted order. Last_Choice gives the position of the last
-- valid choice in Choice_Table, Choice_Table'First contains the first.
-- We can have Last_Choice < Choice_Table'Last for one (or several) of
-- the following reasons:
--
-- (a) The list of choices contained a non static choice
--
-- (b) The list of choices contained an empty choice
-- (something like "1 .. 0 => ")
--
-- (c) One of the bounds of a discrete choice contains an
-- error or raises constraint error.
--
-- In one of the bounds of a discrete choice raises a constraint
-- error the flag Raise_CE is set.
--
-- Finally Others_Present is set to True if an Others choice is present
-- in the list of choices, and in this case the call also sets
-- Others_Discrete_Choices in the N_Others_Choice node.
end Generic_Choices_Processing;
end Sem_Case;
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