+++ /dev/null
-------------------------------------------------------------------------------
--- --
--- GNAT COMPILER COMPONENTS --
--- --
--- E L I S T S --
--- --
--- S p e c --
--- --
--- $Revision: 1.1.16.2 $
--- --
--- Copyright (C) 1992-1998 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 2, 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 COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
--- --
--- As a special exception, if other files instantiate generics from this --
--- unit, or you link this unit with other files to produce an executable, --
--- this unit does not by itself cause the resulting executable to be --
--- covered by the GNU General Public License. This exception does not --
--- however invalidate any other reasons why the executable file might be --
--- covered by the GNU Public License. --
--- --
--- GNAT was originally developed by the GNAT team at New York University. --
--- Extensive contributions were provided by Ada Core Technologies Inc. --
--- --
-------------------------------------------------------------------------------
-
--- This package provides facilities for manipulating lists of nodes (see
--- package Atree for format and implementation of tree nodes). Separate list
--- elements are allocated to represent elements of these lists, so it is
--- possible for a given node to be on more than one element list at a time.
--- See also package Nlists, which provides another form that is threaded
--- through the nodes themselves (using the Link field), which is more time
--- and space efficient, but a node can be only one such list.
-
-with Types; use Types;
-with System;
-
-package Elists is
-
- -- An element list is represented by a header that is allocated in the
- -- Elist header table. This header contains pointers to the first and
- -- last elements in the list, or to No_Elmt if the list is empty.
-
- -- The elements in the list each contain a pointer to the next element
- -- and a pointer to the referenced node. Putting a node into an element
- -- list causes no change at all to the node itself, so a node may be
- -- included in multiple element lists, and the nodes thus included may
- -- or may not be elements of node lists (see package Nlists).
-
- procedure Initialize;
- -- Initialize allocation of element list tables. Called at the start of
- -- compiling each new main source file. Note that Initialize must not be
- -- called if Tree_Read is used.
-
- procedure Lock;
- -- Lock tables used for element lists before calling backend
-
- procedure Tree_Read;
- -- Initializes internal tables from current tree file using Tree_Read.
- -- Note that Initialize should not be called if Tree_Read is used.
- -- Tree_Read includes all necessary initialization.
-
- procedure Tree_Write;
- -- Writes out internal tables to current tree file using Tree_Write
-
- function Last_Elist_Id return Elist_Id;
- -- Returns Id of last allocated element list header
-
- function Elists_Address return System.Address;
- -- Return address of Elists table (used in Back_End for Gigi call)
-
- function Num_Elists return Nat;
- -- Number of currently allocated element lists
-
- function Last_Elmt_Id return Elmt_Id;
- -- Returns Id of last allocated list element
-
- function Elmts_Address return System.Address;
- -- Return address of Elmts table (used in Back_End for Gigi call)
-
- function Node (Elmt : Elmt_Id) return Node_Id;
- pragma Inline (Node);
- -- Returns the value of a given list element. Returns Empty if Elmt
- -- is set to No_Elmt.
-
- function New_Elmt_List return Elist_Id;
- -- Creates a new empty element list. Typically this is used to initialize
- -- a field in some other node which points to an element list where the
- -- list is then subsequently filled in using Append calls.
-
- function First_Elmt (List : Elist_Id) return Elmt_Id;
- pragma Inline (First_Elmt);
- -- Obtains the first element of the given element list or, if the
- -- list has no items, then No_Elmt is returned.
-
- function Last_Elmt (List : Elist_Id) return Elmt_Id;
- pragma Inline (Last_Elmt);
- -- Obtains the last element of the given element list or, if the
- -- list has no items, then No_Elmt is returned.
-
- function Next_Elmt (Elmt : Elmt_Id) return Elmt_Id;
- pragma Inline (Next_Elmt);
- -- This function returns the next element on an element list. The argument
- -- must be a list element other than No_Elmt. Returns No_Elmt if the given
- -- element is the last element of the list.
-
- procedure Next_Elmt (Elmt : in out Elmt_Id);
- pragma Inline (Next_Elmt);
- -- Next_Elmt (Elmt) is equivalent to Elmt := Next_Elmt (Elmt)
-
- function Is_Empty_Elmt_List (List : Elist_Id) return Boolean;
- pragma Inline (Is_Empty_Elmt_List);
- -- This function determines if a given tree id references an element list
- -- that contains no items.
-
- procedure Append_Elmt (Node : Node_Id; To : Elist_Id);
- -- Appends Node at the end of To, allocating a new element.
-
- procedure Prepend_Elmt (Node : Node_Id; To : Elist_Id);
- -- Appends Node at the beginning of To, allocating a new element.
-
- procedure Insert_Elmt_After (Node : Node_Id; Elmt : Elmt_Id);
- -- Add a new element (Node) right after the pre-existing element Elmt
- -- It is invalid to call this subprogram with Elmt = No_Elmt.
-
- procedure Replace_Elmt (Elmt : Elmt_Id; New_Node : Node_Id);
- pragma Inline (Replace_Elmt);
- -- Causes the given element of the list to refer to New_Node, the node
- -- which was previously referred to by Elmt is effectively removed from
- -- the list and replaced by New_Node.
-
- procedure Remove_Elmt (List : Elist_Id; Elmt : Elmt_Id);
- -- Removes Elmt from the given list. The node itself is not affected,
- -- but the space used by the list element may be (but is not required
- -- to be) freed for reuse in a subsequent Append_Elmt call.
-
- procedure Remove_Last_Elmt (List : Elist_Id);
- -- Removes the last element of the given list. The node itself is not
- -- affected, but the space used by the list element may be (but is not
- -- required to be) freed for reuse in a subsequent Append_Elmt call.
-
- function No (List : Elist_Id) return Boolean;
- pragma Inline (No);
- -- Tests given Id for equality with No_Elist. This allows notations like
- -- "if No (Statements)" as opposed to "if Statements = No_Elist".
-
- function Present (List : Elist_Id) return Boolean;
- pragma Inline (Present);
- -- Tests given Id for inequality with No_Elist. This allows notations like
- -- "if Present (Statements)" as opposed to "if Statements /= No_Elist".
-
- function No (Elmt : Elmt_Id) return Boolean;
- pragma Inline (No);
- -- Tests given Id for equality with No_Elmt. This allows notations like
- -- "if No (Operation)" as opposed to "if Operation = No_Elmt".
-
- function Present (Elmt : Elmt_Id) return Boolean;
- pragma Inline (Present);
- -- Tests given Id for inequality with No_Elmt. This allows notations like
- -- "if Present (Operation)" as opposed to "if Operation /= No_Elmt".
-
-end Elists;