1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
/*-----------------------------------------------------------------------
File : ccl_eqnresolution.c
Author: Stephan Schulz
Contents
Routines for performing (ordered) equality resolution.
Copyright 1998, 1999 by the author.
This code is released under the GNU General Public Licence and
the GNU Lesser General Public License.
See the file COPYING in the main E directory for details..
Run "eprover -h" for contact information.
Changes
<1> Fri Jun 5 18:36:46 MET DST 1998
New
-----------------------------------------------------------------------*/
#include "ccl_eqnresolution.h"
/*---------------------------------------------------------------------*/
/* Global Variables */
/*---------------------------------------------------------------------*/
bool EqResOnMaximalLiteralsOnly = true;
/*---------------------------------------------------------------------*/
/* Forward Declarations */
/*---------------------------------------------------------------------*/
/*---------------------------------------------------------------------*/
/* Internal Functions */
/*---------------------------------------------------------------------*/
/*---------------------------------------------------------------------*/
/* Exported Functions */
/*---------------------------------------------------------------------*/
/*-----------------------------------------------------------------------
//
// Function: ComputeEqRes()
//
// Given a clause and a position, try to perform equality
// resolution and return the resulting clause.
//
// Global Variables: -
//
// Side Effects : Creates clause
//
/----------------------------------------------------------------------*/
Clause_p ComputeEqRes(TB_p bank, ClausePos_p pos, VarBank_p freshvars)
{
Subst_p subst;
Clause_p new_clause = NULL;
Eqn_p new_literals;
bool unifies;
assert(!EqnIsPositive(pos->literal));
subst = SubstAlloc();
VarBankResetVCounts(freshvars);
unifies = SubstMguComplete(pos->literal->lterm, pos->literal->rterm,
subst);
if(unifies)
{
NormSubstEqnListExcept(pos->clause->literals, pos->literal,
subst, freshvars);
new_literals = EqnListCopyOptExcept(pos->clause->literals,
pos->literal);
EqnListRemoveResolved(&new_literals);
EqnListRemoveDuplicates(new_literals);
new_clause = ClauseAlloc(new_literals);
}
SubstDelete(subst);
return new_clause;
}
/*-----------------------------------------------------------------------
//
// Function: ClausePosFirstEqResLiteral()
//
// Find the first negative maximal literal in clause and return it.
//
// Global Variables: -
//
// Side Effects : Changes pos.
//
/----------------------------------------------------------------------*/
Eqn_p ClausePosFirstEqResLiteral(Clause_p clause, ClausePos_p pos)
{
pos->clause = clause;
pos->literal = clause->literals;
PStackReset(pos->pos);
while(pos->literal)
{
if(!EqnIsPositive(pos->literal) &&
(!EqResOnMaximalLiteralsOnly || EqnIsMaximal(pos->literal)))
{
break;
}
pos->literal = pos->literal->next;
}
return pos->literal;
}
/*-----------------------------------------------------------------------
//
// Function: ClausePosNextEqResLiteral()
//
// Find the next negative maximal literal in clause and return it.
//
// Global Variables: -
//
// Side Effects : Changes pos.
//
/----------------------------------------------------------------------*/
Eqn_p ClausePosNextEqResLiteral(ClausePos_p pos)
{
pos->literal = pos->literal->next;
while(pos->literal)
{
if(!EqnIsPositive(pos->literal) &&
(!EqResOnMaximalLiteralsOnly || EqnIsMaximal(pos->literal)))
{
break;
}
pos->literal = pos->literal->next;
}
return pos->literal;
}
/*---------------------------------------------------------------------*/
/* End of File */
/*---------------------------------------------------------------------*/
|
