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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));
#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 int
LookupModule(Term a)
{
unsigned int i;
/* prolog module */
if (a == 0)
return 0;
for (i = 0; i < NoOfModules; ++i) {
if (ModuleName[i] == a) {
return i;
}
}
ModuleName[i = NoOfModules++] = a;
if (NoOfModules == MaxModules) {
Yap_Error(SYSTEM_ERROR,a,"number of modules overflowed");
}
return (i);
}
Term
Yap_Module(Term tmod)
{
return ModuleName[LookupModule(tmod)];
}
struct pred_entry *
Yap_ModulePred(Term mod)
{
return ModulePred[LookupModule(mod)];
}
void
Yap_NewModulePred(Term mod, struct pred_entry *ap)
{
Term imod = LookupModule(mod);
ap->NextPredOfModule = ModulePred[imod];
ModulePred[imod] = ap;
}
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)
{ /* $change_module(New) */
Term mod = Deref(ARG1);
LookupModule(mod);
CurrentModule = mod;
return TRUE;
}
static Int
cont_current_module(void)
{
Int imod = IntOfTerm(EXTRA_CBACK_ARG(1,1));
Term t = ModuleName[imod];
if (imod == NoOfModules) {
cut_fail();
}
EXTRA_CBACK_ARG(1,1) = MkIntTerm(imod+1);
return(Yap_unify(ARG1,t));
}
static Int
init_current_module(void)
{ /* current_module(?ModuleName) */
EXTRA_CBACK_ARG(1,1) = MkIntTerm(0);
return (cont_current_module());
}
void
Yap_InitModulesC(void)
{
Yap_InitCPred("$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_InitCPredBack("$all_current_modules", 1, 1, init_current_module, cont_current_module,
SafePredFlag|SyncPredFlag|HiddenPredFlag);
}
void
Yap_InitModules(void)
{
ModuleName[PROLOG_MODULE] =
TermProlog;
ModuleName[1] =
USER_MODULE;
ModuleName[2] =
IDB_MODULE;
ModuleName[3] =
ATTRIBUTES_MODULE;
ModuleName[4] =
CHARSIO_MODULE;
ModuleName[5] =
TERMS_MODULE;
NoOfModules = 6;
CurrentModule = PROLOG_MODULE;
}