func (expr *NullIfExpr) Walk(v Visitor) Expr {
	e1, changed1 := WalkExpr(v, expr.Expr1)
	e2, changed2 := WalkExpr(v, expr.Expr2)
	if changed1 || changed2 {
		exprCopy := *expr
		exprCopy.Expr1 = e1
		exprCopy.Expr2 = e2
		return &exprCopy
	}
	return expr
}
// Walk implements the Expr interface.
Walk implements the Expr interface.
// Walk implements the Expr interface .
func (expr *NullIfExpr) Walk(v Visitor) Expr {
	e1, changed1 := WalkExpr(v, expr.Expr1)
	e2, changed2 := WalkExpr(v, expr.Expr2)
	if changed1 || changed2 {
		exprCopy := *expr
		exprCopy.Expr1 = e1
		exprCopy.Expr2 = e2
		return &exprCopy
	}
	return expr
}
func ( expr * NullIfExpr ) Walk ( v Visitor ) Expr { e1 , changed1 := WalkExpr ( v , expr . Expr1 ) e2 , changed2 := WalkExpr ( v , expr . Expr2 ) if changed1 || changed2 { exprCopy := * expr exprCopy . Expr1 = e1 exprCopy . Expr2 = e2 return & exprCopy } return expr }
Walk implements the Expr interface.
Walk implements the Expr interface .