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#include <u.h>
#include <libc.h>
#include <bio.h>
#include "dat.h"
#include "fns.h"
Module *addemptymodule(Rune *);
Clause *appendclause(Clause *, Clause *);
Predicate *appendpredicate(Predicate *, Predicate *);
void
initmodules(void)
{
systemmodule = parsemodule("./stdlib.pl");
if(systemmodule == nil){
print("Can't load ./stdlib.pl\n");
exits(nil);
}
Predicate *p;
for(p = systemmodule->predicates; p != nil; p = p->next){
p->builtin = 1;
}
usermodule = addemptymodule(L"user");
}
Module *
parsemodule(char *file)
{
Module *m = nil;
int fd = open(file, OREAD);
if(fd < 0)
return nil;
Term *terms = parse(fd, nil, 0);
if(terms == nil)
return nil;
/* Actually look at the terms and convert ':-'/2 terms into clauses.
The only directives (terms of type ':-'/1 there should be in the list are
the module specific ones, as the other are handled by parse itself.
*/
if(terms->tag == CompoundTerm && runestrcmp(terms->text, L":-") == 0 && terms->arity == 1){
Term *directive = terms->children;
if(directive->tag == CompoundTerm && runestrcmp(directive->text, L"module") == 0 && directive->arity == 2){
Term *modulename = directive->children;
Term *publiclist = modulename->next;
if(modulename->tag != AtomTerm){
print("Module name should be an atom in: %S\n", prettyprint(directive, 0, 0, 0));
return nil;
}
print("Public list for module '%S': %S\n", modulename->text, prettyprint(publiclist, 0, 0, 0));
m = addemptymodule(modulename->text);
}
terms = terms->next;
}
Predicate *currentpred = nil;
Term *t;
for(t = terms; t != nil; t = t->next){
Clause *cl = gmalloc(sizeof(Clause));
int arity;
cl->clausenr = 0;
cl->next = nil;
if(t->tag == CompoundTerm && runestrcmp(t->text, L":-") == 0 && t->arity == 2){
cl->head = t->children;
cl->body = t->children->next;
}else{
cl->head = t;
cl->body = nil;
}
if(cl->head->tag == AtomTerm)
arity = 0;
else
arity = cl->head->arity;
/* Figure out if this clause goes into the latest predicate, or if it is the start of a new one */
if(currentpred == nil || runestrcmp(cl->head->text, currentpred->name) != 0 || arity != currentpred->arity){
if(m)
m->predicates = appendpredicate(currentpred, m->predicates);
else
usermodule->predicates = appendpredicate(currentpred, usermodule->predicates);
currentpred = gmalloc(sizeof(Predicate));
currentpred->name = cl->head->text;
currentpred->arity = arity;
currentpred->clauses = cl;
currentpred->public = 1; /* everything is public for now */
currentpred->builtin = 0;
currentpred->next = nil;
}else
currentpred->clauses = appendclause(currentpred->clauses, cl);
}
if(m)
m->predicates = appendpredicate(currentpred, m->predicates);
else
usermodule->predicates = appendpredicate(currentpred, usermodule->predicates);
return m;
}
Module *
getmodule(Rune *name)
{
Module *m;
for(m = modules; m != nil; m = m->next){
if(runestrcmp(m->name, name) == 0)
return m;
}
return nil;
}
Module *
addemptymodule(Rune *name)
{
Module *m = gmalloc(sizeof(Module));
m->name = name;
m->next = modules;
if(systemmodule == nil)
m->predicates = nil;
else
m->predicates = systemmodule->predicates; /* Direct access to system clauses for now, but when I figure out imports this will change */
modules = m;
return m;
}
Clause *
appendclause(Clause *clauses, Clause *new)
{
Clause *tmp;
if(clauses == nil)
return new;
for(tmp = clauses; tmp->next != nil; tmp = tmp->next);
tmp->next = new;
return clauses;
}
Predicate *
appendpredicate(Predicate *preds, Predicate *new)
{
Predicate *tmp;
if(preds == nil)
return new;
for(tmp = preds; tmp->next != nil; tmp = tmp->next);
tmp->next = new;
return preds;
}
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