1 files changed, 36 insertions, 31 deletions

diff --git a/eval.c b/eval.c
index f6cdb0d..11809a8 100644
--- a/eval.c
+++ b/eval.c
@@ -59,47 +59,46 @@ evalfn evalfns[15][15] = {
 };
 
 Datum *
-eval(Datum *tokens, int *ntoks)
+eval(Statement *stmt)
 {
 	errormsg = nil;
 
 	/* start by looking up first variable if needed */
-	if(*ntoks > 0 && tokens[(*ntoks)-1].tag == NameTag){
-		Datum *value = lookup(tokens[(*ntoks)-1]);
+	if(stmt->ntoks > 0 && stmt->toks[stmt->ntoks-1].tag == NameTag){
+		Datum *value = lookup(stmt->toks[stmt->ntoks-1]);
 		if(value == nil)
-			*ntoks = 0;
+			return nil;
 		else
-			tokens[(*ntoks)-1] = *value;
+			stmt->toks[stmt->ntoks-1] = *value;
 	}
 
-	while(*ntoks > 1){
+	while(stmt->ntoks > 1){
 		int maxlevel = 0;
 		int offset;
 		evalfn fn = nil;
-		traceprint("CURRENT: %S\n", ppdatums(tokens, *ntoks));
-		for(offset = (*ntoks)-1; offset >= 0; offset--){
+		traceprint("CURRENT: %S\n", ppdatums(stmt->toks, stmt->ntoks));
+		for(offset = stmt->ntoks-1; offset >= 0; offset--){
 			int level;
 retry:
 			if(offset == 0)
 				level = 0;
 			else{
-				Datum left = tokens[offset-1];
-				Datum right = tokens[offset];
+				Datum left = stmt->toks[offset-1];
+				Datum right = stmt->toks[offset];
 				level = bindingstrengths[left.tag][right.tag];
 			}
 
-			if(level == 0 && tokens[offset-1].tag == NameTag){
-				Datum *value = lookup(tokens[offset-1]);
-				if(value == nil){
-					*ntoks = 0;
-					return tokens;
-				}else{
-					tokens[offset-1] = *value;
+			if(level == 0 && stmt->toks[offset-1].tag == NameTag){
+				Datum *value = lookup(stmt->toks[offset-1]);
+				if(value == nil)
+					return nil;
+				else{
+					stmt->toks[offset-1] = *value;
 					goto retry;
 				}
 			}else if(level < maxlevel){
-				Datum left = tokens[offset];
-				Datum right = tokens[offset+1];
+				Datum left = stmt->toks[offset];
+				Datum right = stmt->toks[offset+1];
 				fn = evalfns[left.tag][right.tag];
 				traceprint("Reducing %S and %S (fn=%p, level=%d, max=%d)\n", ppdatum(left), ppdatum(right), fn, level, maxlevel);
 				break;
@@ -108,15 +107,21 @@ retry:
 		}
 		if(maxlevel == 0){
 			errormsg = L"No reduce rule. Syntax error.";
-			*ntoks = 0;
+			return nil;
 		}else{
-			tokens[offset] = fn(tokens[offset],tokens[offset+1]);
-			for(int i = offset+1; i < (*ntoks)-1; i++)
-				tokens[i] = tokens[i+1];
-			(*ntoks)--;
+			stmt->toks[offset] = fn(stmt->toks[offset],stmt->toks[offset+1]);
+			for(int i = offset+1; i < stmt->ntoks-1; i++)
+				stmt->toks[i] = stmt->toks[i+1];
+			stmt->ntoks--;
 		}
 	}
-	return tokens;
+	if(stmt->ntoks == 1){
+		if(stmt->next)
+			return eval(stmt->next);
+		else
+			return stmt->toks;
+	}else
+		return nil;
 }
 
 Datum *
@@ -173,10 +178,10 @@ Datum
 lpar(Datum left, Datum right)
 {
 	/* build up a parthenthesised expression */
-	left.expr.ntoks++;
-	left.expr.toks = realloc(left.expr.toks, sizeof(Datum) * left.expr.ntoks);
-	left.expr.toks[left.expr.ntoks-1] = right;
-	traceprint("LPAR: %S\n", ppdatums(left.expr.toks, left.expr.ntoks));
+	left.stmt.ntoks++;
+	left.stmt.toks = realloc(left.stmt.toks, sizeof(Datum) * left.stmt.ntoks);
+	left.stmt.toks[left.stmt.ntoks-1] = right;
+	traceprint("LPAR: %S\n", ppdatums(left.stmt.toks, left.stmt.ntoks));
 	return left;
 }
 
@@ -185,8 +190,8 @@ rpar(Datum left, Datum right)
 {
 	/* evaluate a parenthesis expression and return the result */
 	USED(right);
-	traceprint("RPAR: %S\n", ppdatums(left.expr.toks, left.expr.ntoks));
-	Datum *result = eval(left.expr.toks, &left.expr.ntoks);
+	traceprint("RPAR: %S\n", ppdatums(left.stmt.toks, left.stmt.ntoks));
+	Datum *result = eval(&left.stmt);
 	result[0].array->stranded = 0;
 	return result[0]; /* TODO handle error if ntoks != 1 */
 }