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-- Copyright (c) 2013-2014, Natacha Porté --
-- --
-- Permission to use, copy, modify, and distribute this software for any --
-- purpose with or without fee is hereby granted, provided that the above --
-- copyright notice and this permission notice appear in all copies. --
-- --
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES --
-- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF --
-- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR --
-- ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES --
-- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN --
-- ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF --
-- OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. --
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------------------------------------------------------------------------------
-- Natools.S_Expressions.Dynamic_Interpreters provides an implemntation of --
-- a dispatching command interpreter. The base list of a given S-expression --
-- is considered as list of command, either argumentless (atoms) or with a --
-- S-expression argument (sublist). Sublists that don't start with an atom --
-- are silently ignored and can be used as comments. --
-- --
-- Formal types represent common objets for all the command, Shared_State --
-- begin read/write while Shared_Context is read-only. --
------------------------------------------------------------------------------
with Natools.S_Expressions.Lockable;
private with Ada.Containers.Indefinite_Ordered_Maps;
private with Natools.S_Expressions.Atom_Refs;
generic
type Shared_State (<>) is limited private;
type Shared_Context (<>) is limited private;
package Natools.S_Expressions.Dynamic_Interpreters is
pragma Preelaborate (Dynamic_Interpreters);
Command_Not_Found : exception;
type Command is interface;
procedure Execute
(Self : in out Command;
State : in out Shared_State;
Context : in Shared_Context;
Name : in Atom)
is null;
-- Execute a single argumentless command
procedure Execute
(Self : in out Command;
State : in out Shared_State;
Context : in Shared_Context;
Cmd : in out Lockable.Descriptor'Class)
is null;
-- Execute a single command with arguments
type Null_Command is new Command with null record;
Do_Nothing : Null_Command := Null_Command'(null record);
type Interpreter is new Command with private;
pragma Preelaborable_Initialization (Interpreter);
procedure Add_Command
(Self : in out Interpreter;
Name : in Atom;
Cmd : in Command'Class);
procedure Add
(Self : in out Interpreter;
Name : in String;
Cmd : in Command'Class);
function Has_Command (Self : Interpreter; Name : Atom) return Boolean;
function Is_Empty (Self : Interpreter) return Boolean;
procedure Set_Fallback
(Self : in out Interpreter;
Name : in Atom);
procedure Reset_Fallback (Self : in out Interpreter);
not overriding procedure Execute
(Self : in out Interpreter;
Expression : in out Lockable.Descriptor'Class;
State : in out Shared_State;
Context : in Shared_Context);
-- Execute an expression, raising Command_Not_Found on unknown commands
not overriding procedure Execute
(Self : in out Interpreter;
Fallback : in out Command'Class;
Expression : in out Lockable.Descriptor'Class;
State : in out Shared_State;
Context : in Shared_Context);
-- Execute an expression with temporary fallback for unknown commands
overriding procedure Execute
(Self : in out Interpreter;
State : in out Shared_State;
Context : in Shared_Context;
Name : in Atom);
-- Execute a single argumentless command
overriding procedure Execute
(Self : in out Interpreter;
State : in out Shared_State;
Context : in Shared_Context;
Cmd : in out Lockable.Descriptor'Class);
-- Execute a single command with arguments
private
type Exception_Command is new Command with null record;
package Command_Maps is new Ada.Containers.Indefinite_Ordered_Maps
(Atom, Command'Class, Less_Than);
type Interpreter is new Command with record
Commands : Command_Maps.Map;
Max_Length : Count := 0;
Fallback_Name : Atom_Refs.Reference;
end record;
end Natools.S_Expressions.Dynamic_Interpreters;