diff --git a/term.go b/term.go
index 388b05e..f0abf69 100644
--- a/term.go
+++ b/term.go
@@ -217,9 +217,9 @@ func (self *term) evalInfix(ctx ExprContext) (leftValue, rightValue any, err err
 	return
 }
 
-func (self *term) evalPrefix(ctx ExprContext) (rightValue any, err error) {
+func (self *term) evalPrefix(ctx ExprContext) (childValue any, err error) {
 	if err = self.checkOperands(); err == nil {
-		rightValue, err = self.children[0].compute(ctx)
+		childValue, err = self.children[0].compute(ctx)
 	}
 	return
 }