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yap-6.3/C/eval.c
Vítor Santos Costa 137f69ed22 doc support
2014-04-21 11:14:18 +01:00

578 lines
14 KiB
C

/*************************************************************************
* *
* YAP Prolog *
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
* File: eval.c *
* Last rev: *
* mods: *
* comments: arithmetical expression evaluation *
* *
*************************************************************************/
#ifdef SCCS
static char SccsId[] = "%W% %G%";
#endif
/**
@file eval.c
@defgroup arithmetic_preds Arithmetic Predicates
@ingroup arithmetic
@{
*/
#include "Yap.h"
#include "Yatom.h"
#include "YapHeap.h"
#include "eval.h"
#if HAVE_STDARG_H
#include <stdarg.h>
#endif
#include <stdlib.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
static Term Eval(Term t1 USES_REGS);
static Term
get_matrix_element(Term t1, Term t2 USES_REGS)
{
if (!IsPairTerm(t2)) {
if (t2 == MkAtomTerm(AtomLength)) {
Int sz = 1;
while (IsApplTerm(t1)) {
Functor f = FunctorOfTerm(t1);
if (NameOfFunctor(f) != AtomNil) {
return MkIntegerTerm(sz);
}
sz *= ArityOfFunctor(f);
t1 = ArgOfTerm(1, t1);
}
return MkIntegerTerm(sz);
}
Yap_ArithError(TYPE_ERROR_EVALUABLE, t2, "X is Y^[A]");
return FALSE;
}
while (IsPairTerm(t2)) {
Int indx;
Term indxt = Eval(HeadOfTerm(t2) PASS_REGS);
if (!IsIntegerTerm(indxt)) {
Yap_ArithError(TYPE_ERROR_EVALUABLE, t2, "X is Y^[A]");
return FALSE;
}
indx = IntegerOfTerm(indxt);
if (!IsApplTerm(t1)) {
Yap_ArithError(TYPE_ERROR_EVALUABLE, t1, "X is Y^[A]");
return FALSE;
} else {
Functor f = FunctorOfTerm(t1);
if (ArityOfFunctor(f) < indx) {
Yap_ArithError(TYPE_ERROR_EVALUABLE, t1, "X is Y^[A]");
return FALSE;
}
}
t1 = ArgOfTerm(indx, t1);
t2 = TailOfTerm(t2);
}
if (t2 != TermNil) {
Yap_ArithError(TYPE_ERROR_EVALUABLE, t2, "X is Y^[A]");
return FALSE;
}
return Eval(t1 PASS_REGS);
}
static Term
Eval(Term t USES_REGS)
{
if (IsVarTerm(t)) {
LOCAL_ArithError = TRUE;
return Yap_ArithError(INSTANTIATION_ERROR,t,"in arithmetic");
} else if (IsNumTerm(t)) {
return t;
} else if (IsAtomTerm(t)) {
ExpEntry *p;
Atom name = AtomOfTerm(t);
if (EndOfPAEntr(p = RepExpProp(Yap_GetExpProp(name, 0)))) {
/* error */
return Yap_ArithError(TYPE_ERROR_EVALUABLE, t,
"atom %s for arithmetic expression",
RepAtom(name)->StrOfAE);
}
return Yap_eval_atom(p->FOfEE);
} else if (IsApplTerm(t)) {
Functor fun = FunctorOfTerm(t);
if (fun == FunctorString) {
const char *s = StringOfTerm(t);
if (s[1] == '\0')
return MkIntegerTerm(s[0]);
return Yap_ArithError(TYPE_ERROR_EVALUABLE, t,
"string in arithmetic expression");
} else if ((Atom)fun == AtomFoundVar) {
return Yap_ArithError(TYPE_ERROR_EVALUABLE, TermNil,
"cyclic term in arithmetic expression");
} else {
Int n = ArityOfFunctor(fun);
Atom name = NameOfFunctor(fun);
ExpEntry *p;
Term t1, t2;
if (EndOfPAEntr(p = RepExpProp(Yap_GetExpProp(name, n)))) {
Term ti[2];
/* error */
ti[0] = t;
ti[1] = MkIntegerTerm(n);
t = Yap_MkApplTerm(FunctorSlash, 2, ti);
return Yap_ArithError(TYPE_ERROR_EVALUABLE, t,
"functor %s/%d for arithmetic expression",
RepAtom(name)->StrOfAE,n);
}
if (p->FOfEE == op_power && p->ArityOfEE == 2) {
t2 = ArgOfTerm(2, t);
if (IsPairTerm(t2)) {
return get_matrix_element(ArgOfTerm(1, t), t2 PASS_REGS);
}
}
*RepAppl(t) = (CELL)AtomFoundVar;
t1 = Eval(ArgOfTerm(1,t) PASS_REGS);
if (t1 == 0L) {
*RepAppl(t) = (CELL)fun;
return FALSE;
}
if (n == 1) {
*RepAppl(t) = (CELL)fun;
return Yap_eval_unary(p->FOfEE, t1);
}
t2 = Eval(ArgOfTerm(2,t) PASS_REGS);
*RepAppl(t) = (CELL)fun;
if (t2 == 0L)
return FALSE;
return Yap_eval_binary(p->FOfEE,t1,t2);
}
} /* else if (IsPairTerm(t)) */ {
if (TailOfTerm(t) != TermNil) {
return Yap_ArithError(TYPE_ERROR_EVALUABLE, t,
"string must contain a single character to be evaluated as an arithmetic expression");
}
return Eval(HeadOfTerm(t) PASS_REGS);
}
}
Term
Yap_InnerEval(Term t)
{
CACHE_REGS
return Eval(t PASS_REGS);
}
#ifdef BEAM
Int BEAM_is(void);
Int
BEAM_is(void)
{ /* X is Y */
union arith_ret res;
blob_type bt;
bt = Eval(Deref(XREGS[2]), &res);
if (bt==db_ref_e) return (NULL);
return (EvalToTerm(bt,&res));
}
#endif
/**
@class is_2
@anchor is_2
@brief evaluation of arithmetic expressions
<b>? _X_:number is + _Y_:ground is det</b>
This predicate succeeds iff the result of evaluating the expression
_Y_ unifies with _X_. This is the predicate normally used to
perform evaluation of arithmetic expressions:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
X is 2+3*4
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
succeeds with `X = 14`.
*/
static Int
p_is( USES_REGS1 )
{ /* X is Y */
Term out = 0L;
while (!(out = Eval(Deref(ARG2) PASS_REGS))) {
if (LOCAL_Error_TYPE == RESOURCE_ERROR_STACK) {
LOCAL_Error_TYPE = YAP_NO_ERROR;
if (!Yap_gcl(LOCAL_Error_Size, 2, ENV, CP)) {
Yap_Error(RESOURCE_ERROR_STACK, ARG2, LOCAL_ErrorMessage);
return FALSE;
}
} else {
Yap_Error(LOCAL_Error_TYPE, LOCAL_Error_Term, LOCAL_ErrorMessage);
return FALSE;
}
}
return Yap_unify_constant(ARG1,out);
}
/**
@class isnan_1
@anchor isnan_1
@brief True if _X_ is not a number
<b> isnan(? _X_:float) is det</b>
Interface to the IEE754 `isnan` test.
*/
static Int
p_isnan( USES_REGS1 )
{ /* X is Y */
Term out = 0L;
while (!(out = Eval(Deref(ARG1) PASS_REGS))) {
if (LOCAL_Error_TYPE == RESOURCE_ERROR_STACK) {
LOCAL_Error_TYPE = YAP_NO_ERROR;
if (!Yap_gcl(LOCAL_Error_Size, 1, ENV, CP)) {
Yap_Error(RESOURCE_ERROR_STACK, ARG2, LOCAL_ErrorMessage);
return FALSE;
}
} else {
Yap_Error(LOCAL_Error_TYPE, LOCAL_Error_Term, LOCAL_ErrorMessage);
return FALSE;
}
}
if (IsVarTerm(out)) {
Yap_Error(INSTANTIATION_ERROR, out, "isnan/1");
return FALSE;
}
if (!IsFloatTerm(out)) {
Yap_Error(TYPE_ERROR_FLOAT, out, "isnan/1");
return FALSE;
}
return isnan(FloatOfTerm(out));
}
/**
@class isinf_1
@anchor isinf_1
@brief True if _X_ is infinity
<b> isnan(? _X_:float) is det</b>
Interface to the IEE754 `isinf` test.
*/
static Int
p_isinf( USES_REGS1 )
{ /* X is Y */
Term out = 0L;
while (!(out = Eval(Deref(ARG1) PASS_REGS))) {
if (LOCAL_Error_TYPE == RESOURCE_ERROR_STACK) {
LOCAL_Error_TYPE = YAP_NO_ERROR;
if (!Yap_gcl(LOCAL_Error_Size, 1, ENV, CP)) {
Yap_Error(RESOURCE_ERROR_STACK, ARG2, LOCAL_ErrorMessage);
return FALSE;
}
} else {
Yap_Error(LOCAL_Error_TYPE, LOCAL_Error_Term, LOCAL_ErrorMessage);
return FALSE;
}
}
if (IsVarTerm(out)) {
Yap_Error(INSTANTIATION_ERROR, out, "isinf/1");
return FALSE;
}
if (!IsFloatTerm(out)) {
Yap_Error(TYPE_ERROR_FLOAT, out, "isinf/1");
return FALSE;
}
return isinf(FloatOfTerm(out));
}
/**
@class logsum_3
@anchor logsum_3
@brief sum of two logarithms
<b> logsum(+ _Log1_, + _Log2_, - _Out_ ) is det </b>
True if _Log1_ is the logarithm of the positive number _A1_,
_Log2_ is the logarithm of the positive number _A2_, and
_Out_ is the logarithm of the sum of the numbers _A1_ and
_A2_. Useful in probability computation.
*/
static Int
p_logsum( USES_REGS1 )
{ /* X is Y */
Term t1 = Deref(ARG1);
Term t2 = Deref(ARG2);
int done = FALSE;
Float f1, f2;
while (!done) {
if (IsFloatTerm(t1)) {
f1 = FloatOfTerm(t1);
done = TRUE;
} else if (IsIntegerTerm(t1)) {
f1 = IntegerOfTerm(t1);
done = TRUE;
#if USE_GMP
} else if (IsBigIntTerm(t1)) {
f1 = Yap_gmp_to_float(t1);
done = TRUE;
#endif
} else {
while (!(t1 = Eval(t1 PASS_REGS))) {
if (LOCAL_Error_TYPE == RESOURCE_ERROR_STACK) {
LOCAL_Error_TYPE = YAP_NO_ERROR;
if (!Yap_gcl(LOCAL_Error_Size, 1, ENV, CP)) {
Yap_Error(RESOURCE_ERROR_STACK, ARG2, LOCAL_ErrorMessage);
return FALSE;
}
} else {
Yap_Error(LOCAL_Error_TYPE, LOCAL_Error_Term, LOCAL_ErrorMessage);
return FALSE;
}
}
}
}
done = FALSE;
while (!done) {
if (IsFloatTerm(t2)) {
f2 = FloatOfTerm(t2);
done = TRUE;
} else if (IsIntegerTerm(t2)) {
f2 = IntegerOfTerm(t2);
done = TRUE;
#if USE_GMP
} else if (IsBigIntTerm(t2)) {
f2 = Yap_gmp_to_float(t2);
done = TRUE;
#endif
} else {
while (!(t2 = Eval(t2 PASS_REGS))) {
if (LOCAL_Error_TYPE == RESOURCE_ERROR_STACK) {
LOCAL_Error_TYPE = YAP_NO_ERROR;
if (!Yap_gcl(LOCAL_Error_Size, 2, ENV, CP)) {
Yap_Error(RESOURCE_ERROR_STACK, ARG2, LOCAL_ErrorMessage);
return FALSE;
}
} else {
Yap_Error(LOCAL_Error_TYPE, LOCAL_Error_Term, LOCAL_ErrorMessage);
return FALSE;
}
}
}
}
if (f1 >= f2) {
Float fi = exp(f2-f1);
return Yap_unify(ARG3,MkFloatTerm(f1+log(1+fi)));
} else {
Float fi = exp(f1-f2);
return Yap_unify(ARG3,MkFloatTerm(f2+log(1+fi)));
}
}
Int
Yap_ArithError(yap_error_number type, Term where, char *format,...)
{
CACHE_REGS
va_list ap;
LOCAL_ArithError = TRUE;
LOCAL_Error_TYPE = type;
LOCAL_Error_Term = where;
if (!LOCAL_ErrorMessage)
LOCAL_ErrorMessage = LOCAL_ErrorSay;
va_start (ap, format);
if (format != NULL) {
#if HAVE_VSNPRINTF
(void) vsnprintf(LOCAL_ErrorMessage, MAX_ERROR_MSG_SIZE, format, ap);
#else
(void) vsprintf(LOCAL_ErrorMessage, format, ap);
#endif
} else {
LOCAL_ErrorMessage[0] = '\0';
}
va_end (ap);
return 0L;
}
static Int cont_between( USES_REGS1 )
{
Term t1 = EXTRA_CBACK_ARG(3,1);
Term t2 = EXTRA_CBACK_ARG(3,2);
Yap_unify(ARG3, t1);
if (IsIntegerTerm(t1)) {
Int i1;
Term tn;
if (t1 == t2)
cut_succeed();
i1 = IntegerOfTerm(t1);
tn = add_int(i1, 1 PASS_REGS);
EXTRA_CBACK_ARG(3,1) = tn;
HB = B->cp_h = HR;
return TRUE;
} else {
Term t[2];
Term tn;
Int cmp;
cmp = Yap_acmp(t1, t2 PASS_REGS);
if (cmp == 0)
cut_succeed();
t[0] = t1;
t[1] = MkIntTerm(1);
tn = Eval(Yap_MkApplTerm(FunctorPlus, 2, t) PASS_REGS);
EXTRA_CBACK_ARG(3,1) = tn;
HB = B->cp_h = HR;
return TRUE;
}
}
/**
@class between_3
@anchor between_3
@brief sequence of numbers
between(+ _Low_:int, + _High_:int, ? _Value_:int) is nondet
_Low_ and _High_ are integers, _High_ \>= _Low_. If
_Value_ is an integer, _Low_ =\< _Value_
=\< _High_. When _Value_ is a variable it is successively
bound to all integers between _Low_ and _High_. If
_High_ is inf or infinite [between/3](@ref between_3) is true iff
_Value_ \>= _Low_, a feature that is particularly interesting
for generating integers from a certain value.
@}
*/
static Int
init_between( USES_REGS1 )
{
Term t1 = Deref(ARG1);
Term t2 = Deref(ARG2);
if (IsVarTerm(t1)) {
Yap_Error(INSTANTIATION_ERROR, t1, "between/3");
return FALSE;
}
if (IsVarTerm(t2)) {
Yap_Error(INSTANTIATION_ERROR, t1, "between/3");
return FALSE;
}
if (!IsIntegerTerm(t1) &&
!IsBigIntTerm(t1)) {
Yap_Error(TYPE_ERROR_INTEGER, t1, "between/3");
return FALSE;
}
if (!IsIntegerTerm(t2) &&
!IsBigIntTerm(t2) &&
t2 != MkAtomTerm(AtomInf) &&
t2 != MkAtomTerm(AtomInfinity)) {
Yap_Error(TYPE_ERROR_INTEGER, t2, "between/3");
return FALSE;
}
if (IsIntegerTerm(t1) && IsIntegerTerm(t2)) {
Int i1 = IntegerOfTerm(t1);
Int i2 = IntegerOfTerm(t2);
Term t3;
t3 = Deref(ARG3);
if (!IsVarTerm(t3)) {
if (!IsIntegerTerm(t3)) {
if (!IsBigIntTerm(t3)) {
Yap_Error(TYPE_ERROR_INTEGER, t3, "between/3");
return FALSE;
}
cut_fail();
} else {
Int i3 = IntegerOfTerm(t3);
if (i3 >= i1 && i3 <= i2)
cut_succeed();
cut_fail();
}
}
if (i1 > i2) cut_fail();
if (i1 == i2) {
Yap_unify(ARG3, t1);
cut_succeed();
}
} else if (IsIntegerTerm(t1) && IsAtomTerm(t2)) {
Int i1 = IntegerOfTerm(t1);
Term t3;
t3 = Deref(ARG3);
if (!IsVarTerm(t3)) {
if (!IsIntegerTerm(t3)) {
if (!IsBigIntTerm(t3)) {
Yap_Error(TYPE_ERROR_INTEGER, t3, "between/3");
return FALSE;
}
cut_fail();
} else {
Int i3 = IntegerOfTerm(t3);
if (i3 >= i1)
cut_succeed();
cut_fail();
}
}
} else {
Term t3 = Deref(ARG3);
Int cmp;
if (!IsVarTerm(t3)) {
if (!IsIntegerTerm(t3) && !IsBigIntTerm(t3)) {
Yap_Error(TYPE_ERROR_INTEGER, t3, "between/3");
return FALSE;
}
if (Yap_acmp(t3, t1 PASS_REGS) >= 0 && Yap_acmp(t2,t3 PASS_REGS) >= 0 && P != FAILCODE)
cut_succeed();
cut_fail();
}
cmp = Yap_acmp(t1, t2 PASS_REGS);
if (cmp > 0) cut_fail();
if (cmp == 0) {
Yap_unify(ARG3, t1);
cut_succeed();
}
}
EXTRA_CBACK_ARG(3,1) = t1;
EXTRA_CBACK_ARG(3,2) = t2;
return cont_between( PASS_REGS1 );
}
void
Yap_InitEval(void)
{
/* here are the arithmetical predicates */
Yap_InitConstExps();
Yap_InitUnaryExps();
Yap_InitBinaryExps();
Yap_InitCPred("is", 2, p_is, 0L);
Yap_InitCPred("isnan", 1, p_isnan, TestPredFlag);
Yap_InitCPred("isinf", 1, p_isinf, TestPredFlag);
Yap_InitCPred("logsum", 3, p_logsum, TestPredFlag);
Yap_InitCPredBack("between", 3, 2, init_between, cont_between, 0);
}