// Eval implements the Expression Eval interface.
func (f *FunctionCast) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error) {
value, err := f.Expr.Eval(ctx, args)
if err != nil {
return nil, errors.Trace(err)
}
v, ok := value.(*types.DataItem)
if ok {
value = v.Data
}
d := &types.DataItem{Type: f.Tp}
// Casting nil to any type returns null
if value == nil {
d.Data = nil
return d, nil
}
d.Data, err = types.Cast(value, f.Tp)
if err != nil {
return nil, errors.Trace(err)
}
return d, nil
}
// Eval implements the Expression Eval interface.
func (f *FunctionCast) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error) {
value, err := f.Expr.Eval(ctx, args)
if err != nil {
return nil, err
}
// Casting nil to any type returns null
if value == nil {
return nil, nil
}
return types.Cast(value, f.Tp), nil
}
func (e *Evaluator) funcCast(v *ast.FuncCastExpr) bool {
value := v.Expr.GetValue()
// Casting nil to any type returns null
if value == nil {
v.SetValue(nil)
return true
}
var err error
value, err = types.Cast(value, v.Tp)
if err != nil {
e.err = errors.Trace(err)
return false
}
v.SetValue(value)
return true
}