// Eval is a helper function evaluates expression v and do a panic if evaluating error.
func Eval(v expression.Expression, ctx context.Context, env map[interface{}]interface{}) (y interface{}) {
var err error
y, err = v.Eval(ctx, env)
if err != nil {
panic(err) // panic ok here
}
return
}
// EvalBoolExpr evaluates an expression and convert its return value to bool.
func EvalBoolExpr(ctx context.Context, expr expression.Expression, m map[interface{}]interface{}) (bool, error) {
val, err := expr.Eval(ctx, m)
if err != nil {
return false, err
}
if val == nil {
return false, nil
}
x, err := types.ToBool(val)
if err != nil {
return false, err
}
return x != 0, nil
}
func staticExpr(e expression.Expression) (expression.Expression, error) {
if e.IsStatic() {
v, err := e.Eval(nil, nil)
if err != nil {
return nil, err
}
if v == nil {
return Value{nil}, nil
}
return Value{v}, nil
}
return e, nil
}
func (r *WhereRset) planStatic(ctx context.Context, e expression.Expression) (plan.Plan, error) {
val, err := e.Eval(nil, nil)
if err != nil {
return nil, err
}
if val == nil {
// like `select * from t where null`.
return &plans.NullPlan{Fields: r.Src.GetFields()}, nil
}
n, err := types.ToBool(val)
if err != nil {
return nil, err
}
if n == 0 {
// like `select * from t where 0`.
return &plans.NullPlan{Fields: r.Src.GetFields()}, nil
}
return &plans.FilterDefaultPlan{Plan: r.Src, Expr: e}, nil
}