func (e *Evaluator) funcCall(v *ast.FuncCallExpr) bool { f, ok := Funcs[v.FnName.L] if !ok { e.err = ErrInvalidOperation.Gen("unknown function %s", v.FnName.O) return false } if len(v.Args) < f.MinArgs || (f.MaxArgs != -1 && len(v.Args) > f.MaxArgs) { e.err = ErrInvalidOperation.Gen("number of function arguments must in [%d, %d].", f.MinArgs, f.MaxArgs) return false } a := make([]types.Datum, len(v.Args)) for i, arg := range v.Args { a[i] = *arg.GetDatum() } val, err := f.F(a, e.ctx) if err != nil { e.err = errors.Trace(err) return false } v.SetDatum(val) return true }