Fixes error in how env.Find() propagated errors from parent envs

environment.go

@@ -21,8 +21,8 @@ func (e *env) Find(s symbol) (*env, error) {
 			return nil, fmt.Errorf("Symbol %q is not defined", s)
 		}
 	} else {
-		en, _ := e.outer.Find(s)
-		return en, nil
+		en, err := e.outer.Find(s)
+		return en, err
 	}
 }
 

interpreter.go

@@ -499,19 +499,16 @@ func eval(exp expression, en *env) (value expression) {
 			}
 			value = true
 			var err error
-			for i := range e {
-				if i == 0 {
-					continue
-				}
+			for i := range e[1:] {
 				doPanic := panicOnException
 				if doPanic {
 					panicOnException = false
 				}
 				_, ok := e[i].([]expression)
 				if ok {
-					_, err = en.Find(symbol(String(eval(e[i], en), false)))
+					_, err = en.Find(symbol(String(eval(e[i+1], en), false)))
 				} else {
-					_, err = en.Find(symbol(String(e[i], false)))
+					_, err = en.Find(symbol(String(e[i+1], false)))
 				}
 				if doPanic {
 					panicOnException = true