iris

commit 8cef3fb9e1ef5a63979d9b322df0f596dfdcbc8d
parent fd3af754458188e6727981c9746ab96379225a67
Author: sin <sin@2f30.org>
Date:   Wed, 14 May 2014 17:17:58 +0100

Add environment handling

Diffstat:
M
sym.c
 | 
56
++++++++++++++++++++++++++++++++++++++++++++------------
M
sym.h
 | 
3
+++

2 files changed, 47 insertions(+), 12 deletions(-)
diff --git a/sym.c b/sym.c
@@ -9,13 +9,17 @@ struct symentry {
 	struct object *o;
 };
 
+#define NRMAXENV 16
 #define NRMAXSYM 1024
 
-/* we will switch to a hash table later */
-struct symtab {
-	struct symentry e[NRMAXSYM];
-	size_t sz;
-} symtab;
+struct env {
+	struct symtab {
+		struct symentry se[NRMAXSYM];
+		size_t sz;
+	} symtab;
+} env[NRMAXENV];
+
+static struct env *topenv;
 
 struct object *
 addsym(const char *s, struct object *o)
@@ -26,25 +30,53 @@ addsym(const char *s, struct object *o)
 	otmp = lookupsym(s);
 	if (otmp)
 		return otmp;
-	if (symtab.sz + 1 > LEN(symtab.e))
+	if (topenv->symtab.sz + 1 > LEN(topenv->symtab.se))
 		return NULL;
-	se = &symtab.e[symtab.sz];
+	se = &topenv->symtab.se[topenv->symtab.sz];
 	se->s = s;
 	se->o = o;
-	symtab.sz++;
+	topenv->symtab.sz++;
 	return o;
 }
 
 struct object *
 lookupsym(const char *s)
 {
+	struct env *e;
 	struct symentry *se;
 	size_t i;
 
-	for (i = 0; i < symtab.sz; i++) {
-		se = &symtab.e[i];
-		if (strcmp(se->s, s) == 0)
-			return se->o;
+	for (e = topenv; e >= &env[0]; e--) {
+		for (i = 0; i < e->symtab.sz; i++) {
+			se = &e->symtab.se[i];
+			if (strcmp(se->s, s) == 0)
+				return se->o;
+		}
 	}
 	return NULL;
 }
+
+int
+initenv(void)
+{
+	topenv = &env[0];
+	return 0;
+}
+
+int
+pushenv(void)
+{
+	if (topenv +  1 >= &env[NRMAXENV])
+		return -1;
+	topenv++;
+	return 0;
+}
+
+int
+popenv(void)
+{
+	if (topenv - 1 < &env[0])
+		return -1;
+	topenv--;
+	return 0;
+}
diff --git a/sym.h b/sym.h
@@ -3,3 +3,6 @@ struct object;
 
 struct object *addsym(const char *, struct object *);
 struct object *lookupsym(const char *);
+int initenv();
+int pushenv();
+int popenv();