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yap-6.3/C/modules.c

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/*************************************************************************
* *
* YAP Prolog *
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
File: modules.c *
* Last rev: *
* mods: *
* comments: module support *
* *
*************************************************************************/
#ifdef SCCS
static char SccsId[] = "%W% %G%";
#endif
#include "Yap.h"
#include "Yatom.h"
#include "Heap.h"
STATIC_PROTO(Int p_current_module, (void));
STATIC_PROTO(Int p_current_module1, (void));
inline static ModEntry *
FetchModuleEntry(Atom at)
/* get predicate entry for ap/arity; create it if neccessary. */
{
Prop p0;
AtomEntry *ae = RepAtom(at);
READ_LOCK(ae->ARWLock);
p0 = ae->PropsOfAE;
while (p0) {
ModEntry *me = RepModProp(p0);
if ( me->KindOfPE == ModProperty
) {
READ_UNLOCK(ae->ARWLock);
return me;
}
p0 = me->NextOfPE;
}
READ_UNLOCK(ae->ARWLock);
return NULL;
}
inline static ModEntry *
GetModuleEntry(Atom at)
/* get predicate entry for ap/arity; create it if neccessary. */
{
Prop p0;
AtomEntry *ae = RepAtom(at);
ModEntry *new;
p0 = ae->PropsOfAE;
while (p0) {
ModEntry *me = RepModProp(p0);
if ( me->KindOfPE == ModProperty
) {
return me;
}
p0 = me->NextOfPE;
}
new = (ModEntry *) Yap_AllocAtomSpace(sizeof(*new));
INIT_RWLOCK(new->ModRWLock);
new->KindOfPE = ModProperty;
new->PredForME = NULL;
new->NextME = CurrentModules;
CurrentModules = new;
new->AtomOfME = ae;
new->NextOfPE = ae->PropsOfAE;
ae->PropsOfAE = AbsModProp(new);
return new;
}
#define ByteAdr(X) ((char *) &(X))
Term
Yap_Module_Name(PredEntry *ap)
{
Term mod;
if (!ap->ModuleOfPred)
/* If the system predicate is a metacall I should return the
module for the metacall, which I will suppose has to be
reachable from the current module anyway.
So I will return the current module in case the system
predicate is a meta-call. Otherwise it will still work.
*/
mod = CurrentModule;
else {
mod = ap->ModuleOfPred;
}
if (mod) return mod;
return TermProlog;
}
static ModEntry *
LookupModule(Term a)
{
Atom at;
ModEntry *me;
/* prolog module */
if (a == 0)
return GetModuleEntry(AtomOfTerm(TermProlog));
at = AtomOfTerm(a);
me = GetModuleEntry(at);
return me;
}
Term
Yap_Module(Term tmod)
{
LookupModule(tmod);
return tmod;
}
struct pred_entry *
Yap_ModulePred(Term mod)
{
ModEntry *me;
if (!(me = LookupModule(mod)))
return NULL;
return me->PredForME;
}
void
Yap_NewModulePred(Term mod, struct pred_entry *ap)
{
ModEntry *me;
if (!(me = LookupModule(mod)))
return;
WRITE_LOCK(me->ModRWLock);
ap->NextPredOfModule = me->PredForME;
me->PredForME = ap;
WRITE_UNLOCK(me->ModRWLock);
}
static Int
p_current_module(void)
{ /* $current_module(Old,New) */
Term t;
if (CurrentModule) {
if(!Yap_unify_constant(ARG1, CurrentModule))
return FALSE;
} else {
if (!Yap_unify_constant(ARG1, TermProlog))
return FALSE;
}
t = Deref(ARG2);
if (IsVarTerm(t) || !IsAtomTerm(t))
return FALSE;
if (t == TermProlog) {
CurrentModule = PROLOG_MODULE;
} else {
CurrentModule = t;
LookupModule(CurrentModule);
}
return TRUE;
}
static Int
p_current_module1(void)
{ /* $current_module(Old) */
if (CurrentModule)
return Yap_unify_constant(ARG1, CurrentModule);
return Yap_unify_constant(ARG1, TermProlog);
}
static Int
p_change_module(void)
{ /* $change_module(New) */
Term mod = Deref(ARG1);
LookupModule(mod);
CurrentModule = mod;
return TRUE;
}
static Int
cont_current_module(void)
{
ModEntry *imod = (ModEntry *)IntegerOfTerm(EXTRA_CBACK_ARG(1,1)), *next;
Term t = MkAtomTerm(imod->AtomOfME);
next = imod->NextME;
/* ARG1 is unbound */
Yap_unify(ARG1,t);
if (!next)
cut_succeed();
EXTRA_CBACK_ARG(1,1) = MkIntegerTerm((Int)next);
return TRUE;
}
static Int
init_current_module(void)
{ /* current_module(?ModuleName) */
Term t = Deref(ARG1);
if (!IsVarTerm(t)) {
if (!IsAtomTerm(t)) {
Yap_Error(TYPE_ERROR_ATOM,t,"module name must be an atom");
return FALSE;
}
if (FetchModuleEntry(AtomOfTerm(t)) != NULL)
cut_succeed();
cut_fail();
}
EXTRA_CBACK_ARG(1,1) = MkIntegerTerm((Int)CurrentModules);
return cont_current_module();
}
static Int
p_strip_module(void)
{
Term t1 = Deref(ARG1), t2, tmod = CurrentModule;
if (tmod == PROLOG_MODULE) {
tmod = TermProlog;
}
if (IsVarTerm(t1) ||
!IsApplTerm(t1) ||
FunctorOfTerm(t1) != FunctorModule ||
IsVarTerm(t2 = ArgOfTerm(1,t1)) ||
!IsAtomTerm(t2)) {
return Yap_unify(ARG3, t1) &&
Yap_unify(ARG2, tmod);
}
do {
tmod = t2;
t1 = ArgOfTerm(2,t1);
} while (!IsVarTerm(t1) &&
IsApplTerm(t1) &&
FunctorOfTerm(t1) == FunctorModule &&
!IsVarTerm(t2 = ArgOfTerm(1,t1)) &&
IsAtomTerm(t2));
return Yap_unify(ARG3, t1) &&
Yap_unify(ARG2, tmod);
}
void
Yap_InitModulesC(void)
{
Yap_InitCPred("$current_module", 2, p_current_module, SafePredFlag|SyncPredFlag|HiddenPredFlag);
Yap_InitCPred("$current_module", 1, p_current_module1, SafePredFlag|SyncPredFlag|HiddenPredFlag);
Yap_InitCPred("$change_module", 1, p_change_module, SafePredFlag|SyncPredFlag|HiddenPredFlag);
Yap_InitCPred("strip_module", 3, p_strip_module, SafePredFlag|SyncPredFlag|HiddenPredFlag);
Yap_InitCPredBack("$all_current_modules", 1, 1, init_current_module, cont_current_module,
SafePredFlag|SyncPredFlag|HiddenPredFlag);
}
void
Yap_InitModules(void)
{
LookupModule(MkAtomTerm(Yap_LookupAtom("prolog")));
LookupModule(USER_MODULE);
LookupModule(IDB_MODULE);
LookupModule(ATTRIBUTES_MODULE);
LookupModule(CHARSIO_MODULE);
LookupModule(TERMS_MODULE);
LookupModule(SYSTEM_MODULE);
LookupModule(READUTIL_MODULE);
LookupModule(HACKS_MODULE);
LookupModule(ARG_MODULE);
LookupModule(GLOBALS_MODULE);
CurrentModule = PROLOG_MODULE;
}