%-----------------------------------------------------------------------------%
% Copyright (C) 1995-1998, 2003-2005 The University of Melbourne.
% This file may only be copied under the terms of the GNU General
% Public License - see the file COPYING in the Mercury distribution.
%-----------------------------------------------------------------------------%
% File: transform.m
% Main author: bromage.
%
% This module defines the primitive operations that may be performed
% on a logic program.  These include:
%
%	- unfold (NYI)
%	  Replaces a goal with its possible expansions.
%
%	- fold (NYI)
%	  Opposite of unfold (not surprisingly).
%
%	- definition (NYI)
%	  Define a new predicate with a given goal.
%
%	- identity (NYI)
%	  Apply an identity (such as the associative law for
%	  addition) to a goal.
%
% These operations form the basis of most high-level transformations.
%
% Also included is a conjunction rescheduler.  Useful just in case
% your transformer upset the ordering in a conjunction.
%-----------------------------------------------------------------------------%

:- module transform_hlds__transform.
:- interface.

:- import_module check_hlds__mode_info.
:- import_module hlds__hlds_goal.

:- import_module list.

:- pred transform__reschedule_conj(list(hlds_goal)::in, list(hlds_goal)::out,
	mode_info::in, mode_info::out) is det.

%-----------------------------------------------------------------------------%
%-----------------------------------------------------------------------------%

:- implementation.

:- import_module check_hlds__delay_info.
:- import_module check_hlds__mode_util.
:- import_module hlds__instmap.
:- import_module parse_tree__prog_data.

:- import_module map.
:- import_module require.
:- import_module set.
:- import_module std_util.
:- import_module term.
:- import_module varset.

%-----------------------------------------------------------------------------%

transform__reschedule_conj([], [], !ModeInfo).
transform__reschedule_conj([Goal0 | Goals0], Goals, !ModeInfo) :-
	mode_info_get_instmap(!.ModeInfo, InstMap0),
	mode_info_get_delay_info(!.ModeInfo, DelayInfo0),

	delay_info__wakeup_goals(WokenGoals, DelayInfo0, DelayInfo1),
	mode_info_set_delay_info(DelayInfo1, !ModeInfo),
	( WokenGoals \= [] ->
		list__append(WokenGoals, [Goal0 | Goals0], Goals1),
		transform__reschedule_conj(Goals1, Goals, !ModeInfo)
	;
		Goal0 = _Goal0Goal - Goal0Info,
		goal_info_get_instmap_delta(Goal0Info, InstMapDelta),
		instmap__apply_instmap_delta(InstMap0, InstMapDelta, InstMap1),
		mode_info_set_instmap(InstMap1, !ModeInfo),
		transform__reschedule_conj(Goals0, Goals1, !ModeInfo),
		Goals = [Goal0 | Goals1]
	).

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