new operator dot '.' used to select an item or character from a list or a string respectively

term.go

@@ -24,6 +24,7 @@ const (
 	priSign
 	priFact
 	priCoalesce
+	priDot
 	priValue
 )
 
@@ -166,7 +167,7 @@ func (self *term) checkOperands() (err error) {
 	switch self.position {
 	case posInfix:
 		if self.children == nil || len(self.children) != 2 || self.anyChildrenNil() {
-			err = self.tk.Errorf("infix operator %q requires two not nil operands, got %d", self.source(), self.getChildrenCount())
+			err = self.tk.Errorf("infix operator %q requires two non-nil operands, got %d", self.source(), self.getChildrenCount())
 		}
 	case posPrefix:
 		if self.children == nil || len(self.children) != 1 || self.children[0] == nil {