interpreter/coster.go

// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package interpreter

import "math"

// Coster calculates the heuristic cost incurred during evaluation.
type Coster interface {
	Cost() (min, max int64)
}

// estimateCost returns the heuristic cost interval for the program.
func estimateCost(i interface{}) (min, max int64) {
	c, ok := i.(Coster)
	if !ok {
		return 0, math.MaxInt64
	}
	return c.Cost()
}