From 44ab8a339c78bcc3460d44b2f435116f21faa60a Mon Sep 17 00:00:00 2001
From: Peter Mikkelsen <peter@pmikkelsen.com>
Date: Mon, 5 Jul 2021 16:27:38 +0000
Subject: First step on modules. Still very very rough.

---
 module.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 116 insertions(+)
 create mode 100644 module.c

(limited to 'module.c')

diff --git a/module.c b/module.c
new file mode 100644
index 0000000..f3ab01b
--- /dev/null
+++ b/module.c
@@ -0,0 +1,116 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+
+#include "dat.h"
+#include "fns.h"
+
+Module *addemptymodule(Rune *);
+Clause *appendclause(Clause *, Clause *);
+
+void
+initmodules(void)
+{
+	systemmodule = parsemodule("./stdlib.pl");
+	if(systemmodule == nil){
+		print("Can't load ./stdlib.pl\n");
+		exits(nil);
+	}
+
+	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;
+	}
+
+	Term *t;
+	for(t = terms; t != nil; t = t->next){
+		Clause *cl = malloc(sizeof(Clause));
+		cl->clausenr = 0;
+		cl->public = 1; /* everything is public for now */
+		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(m == nil)
+			usermodule->clauses = appendclause(usermodule->clauses, cl);
+		else
+			m->clauses = appendclause(m->clauses, cl);
+	}
+
+	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 = malloc(sizeof(Module));
+	m->name = name;
+	m->next = modules;
+
+	if(systemmodule == nil)
+		m->clauses = nil;
+	else
+		m->clauses = systemmodule->clauses; /* 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;
+}
\ No newline at end of file
-- 
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