Implement better error handling, but still no error guards

1 files changed, 17 insertions, 32 deletions

diff --git a/eval.c b/eval.c
index e794a38..bfe211e 100644
--- a/eval.c
+++ b/eval.c
@@ -6,7 +6,6 @@
 
 #define traceprint if(traceeval)print
 
-Rune *errormsg;
 int traceeval;
 
 typedef Datum (*evalfn)(Datum, Datum);
@@ -54,16 +53,9 @@ evalfn evalfns[11][11] = {
 Datum *
 eval(Statement *stmt, int toplevel)
 {
-	errormsg = nil;
-
 	/* start by looking up first variable if needed */
-	if(stmt->ntoks > 0 && stmt->toks[stmt->ntoks-1].tag == NameTag){
-		Datum *value = lookup(stmt->toks[stmt->ntoks-1]);
-		if(value == nil)
-			return nil;
-		else
-			stmt->toks[stmt->ntoks-1] = *value;
-	}
+	if(stmt->ntoks > 0 && stmt->toks[stmt->ntoks-1].tag == NameTag)
+		stmt->toks[stmt->ntoks-1] = *lookup(stmt->toks[stmt->ntoks-1]);;
 
 	while(stmt->ntoks > 1){
 		int maxlevel = 0;
@@ -82,13 +74,8 @@ retry:
 			}
 
 			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;
-				}
+				stmt->toks[offset-1] = *lookup(stmt->toks[offset-1]);
+				goto retry;
 			}else if(level < maxlevel){
 				Datum left = stmt->toks[offset];
 				Datum right = stmt->toks[offset+1];
@@ -98,10 +85,9 @@ retry:
 			}else if(level > maxlevel)
 				maxlevel = level;
 		}
-		if(maxlevel == 0){
-			errormsg = L"No reduce rule. Syntax error.";
-			return nil;
-		}else{
+		if(maxlevel == 0)
+			throwerror(L"No reduce rule", EParse);
+		else{
 			Datum new = fn(stmt->toks[offset],stmt->toks[offset+1]);
 			traceprint("handler fn done\n");
 			if(stmt->toks[offset].tag == ArrayTag)
@@ -135,12 +121,13 @@ retry:
 				guardOK = 0;
 			else if(stmt->toks[0].array->intdata[0] != 0 && stmt->toks[0].array->intdata[0] != 1)
 				guardOK = 0;
-			if(!guardOK){
-				print("Guard expected single valued boolean\n");
-				exits(nil);
+			if(!guardOK)
+				throwerror(L"Guard expected single valued boolean", EDomain);
+			else{
+				stop = 0;
+				if(stmt->toks[0].array->intdata[0] == 1)
+					return eval(stmt->guard, toplevel);
 			}
-			if(stmt->toks[0].array->intdata[0] == 1)
-				return eval(stmt->guard, toplevel);
 		}
 		if(stmt->next && !stop)
 			return eval(stmt->next, toplevel);
@@ -156,8 +143,8 @@ lookup(Datum var)
 	traceprint("VAR LOOKUP %S\n", var.symbol->name);
 
 	if(var.symbol->undefined){
-		errormsg = runesmprint("Variable undefined: %S\n", var.symbol->name);
-		return nil;
+		Rune *msg = runesmprint("Undefined name: %S", var.symbol->name);
+		throwerror(msg, EValue);
 	}
 
 	Datum *val;
@@ -240,10 +227,8 @@ assign(Datum left, Datum right)
 {
 	if(left.symbol->setfn != nil){
 		int ok = left.symbol->setfn(right);
-		if(!ok){
-			print("Assignment failed\n");
-			exits(nil);
-		}
+		if(!ok)
+			throwerror(nil, ESyntax);
 	}else{
 		if(left.symbol->undefined == 0 && left.symbol->value.tag == ArrayTag)
 			freearray(left.symbol->value.array);