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/* IELR's inadequacy list.
Copyright (C) 2009-2015, 2018-2021 Free Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT 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
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#ifndef INADEQUACY_LIST_H_
# define INADEQUACY_LIST_H_
# include <bitset.h>
# include "gram.h"
# include "state.h"
# include "symtab.h"
/**
* A unique ID assigned to every \c InadequacyList node.
*/
typedef long long InadequacyListNodeCount;
/**
* For a conflict, each rule in the grammar can have at most one contributing
* reduction except that rule 0 cannot have any because the reduction on rule 0
* cannot have lookaheads. For a conflict, exactly one shift can contribute.
* Thus the number of rules in the grammar is an upper bound on the number of
* possible contributions to any conflict. The maximum number of possible
* items in a state is also an upper bound, but the \c nitems member of \c
* state is currently a \c size_t and thus, if changed, risks becoming out of
* sync with this type. Whatever the type, it must support negatives for sake
* of the special values below.
*/
typedef rule_number ContributionIndex;
/* Special \c ContributionIndex used to indicate null result when looking for a
contribution. */
extern ContributionIndex const ContributionIndex__none;
/* Special \c ContributionIndex used by
\c AnnotationList__computeDominantContribution to signal when the action
chosen in a conflict is a syntax error because of a %nonassoc. */
extern ContributionIndex const ContributionIndex__error_action;
/**
* The description of a conflict. Don't break encapsulation by modifying the
* fields directly. Use the provided interface functions for
* \c InadequacyList.
*/
typedef struct {
/** The \c token passed to \c InadequacyList__new_conflict. */
symbol *token;
/** The \c actions passed to \c InadequacyList__new_conflict. */
bitset actions;
} Conflict;
/**
* A node in a list that describes all the inadequacies that manifest in a
* particular state. Don't break encapsulation by modifying the fields
* directly. Use the provided interface functions.
*/
typedef struct InadequacyList {
struct InadequacyList *next;
InadequacyListNodeCount id;
state *manifestingState;
ContributionIndex contributionCount;
union {
Conflict conflict;
} inadequacy;
} InadequacyList;
/**
* \pre
* - <tt>manifesting_state != NULL</tt>.
* - \c token is a token.
* - The size of \c actions is
* <tt>manifesting_state->reductions->num + 1</tt>.
* - If the set of all \c InadequacyList nodes with which the new
* \c InadequacyList node might be compared is currently empty, then
* it is best if <tt>*node_count</tt> is zero so that the node count
* does not eventually overflow. However, if that set is not
* currently empty, then <tt>*node_count</tt> has not been modified
* by any function except \c InadequacyList__new_conflict since the
* invocation of \c InadequacyList__new_conflict that constructed
* the first existing member of that set.
* \post
* - \c result is a new \c InadequacyList with one node indicating that, in
* \c manifesting_state, the following actions are in conflict on \c token:
* - Shift iff
* <tt>bitset_test (actions, manifesting_state->reductions->num)</tt>.
* - For any \c i such that
* <tt>0 <= i < manifesting_state->reductions->num</tt>, the reduction
* for the rule <tt>manifesting_state->reductions->rules[i]</tt> iff
* <tt>actions[i]</tt> is set.
* - Given any node \c n from the set of all existing
* \c InadequacyList nodes with which \c result might be compared
* such that <tt>n != result</tt>, then <tt>n->id < result->id</tt>.
* - \c result assumes responsibility for the memory of \c actions.
*/
InadequacyList *InadequacyList__new_conflict (
state *manifesting_state, symbol *token, bitset actions,
InadequacyListNodeCount *node_count);
/**
* \post
* - All memory associated with all nodes in the list \c self was freed.
*/
void InadequacyList__delete (InadequacyList *self);
/**
* \pre
* - <tt>self != NULL</tt>.
* \post
* - \c result = either:
* - \c ContributionIndex__none iff there is no shift contribution in
* \c self (perhaps because \c self isn't a conflict).
* - The index of the shift contribution, otherwise.
*/
ContributionIndex
InadequacyList__getShiftContributionIndex (InadequacyList const *self);
/**
* \pre
* - <tt>self != NULL</tt>.
* - <tt>0 <= i < self->contributionCount</tt>.
* \post
* - \c result = the token associated with contribution \c i in the
* inadequacy described by the node \c self.
*/
symbol *InadequacyList__getContributionToken (InadequacyList const *self,
ContributionIndex i);
/**
* \pre
* - \c self is a single node.
* - <tt>list != NULL</tt>.
* \post
* - \c list now contains \c self as its first node.
* - \c list assumes responsibility for the memory of \c self.
*/
void InadequacyList__prependTo (InadequacyList *self, InadequacyList **list);
#endif /* !INADEQUACY_LIST_H_ */
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