Question

我的项目安排如下

github.com/achanda/poke
├── cmd
│   └── poke.go
├── scanner.go
├── txt_scanner.go
└── types.go

文件如下

# cat scanner.go
package poke

type Scanner interface {
    Scan() *ScanResult
}

# cat txt_scanner.go
package poke

type txtScanner struct {
    txt string
}

func newTxtScanner(host string) Scanner {
    return txtScanner{txt}
}

func (tcpcs txtScanner) Scan() *ScanResult {
    // do stuff
    return &result
}

现在我试图在我的主程序包（poke.go）中调用它，就像这样

package main

import "github.com/achanda/poke"

func main() {
    var sr poke.Scanner
    sr = poke.txtScanner{txt}
    sr.Scan()
}

无法使用

运行

# command-line-arguments
./poke.go:111: cannot refer to unexported name poke.txtScanner
./poke.go:111: undefined: portscan.txtScanner

我做错了什么？

Answer 1

您需要访问包外的类型或字段，因此您应该使用首字母大写导出它们：

首先，您应该使用第一个大写字母来定义txtScanner和txt string，否则您也会看到此错误：

.\poke.go:8: implicit assignment of unexported field 'txt' in poke.TxtScanner literal

像这样：

type TxtScanner struct {
    Txt string
}

在此工作示例代码中也会看到newTxtScanner(host string)函数：
poke.go：

package main

import "github.com/achanda/poke"

func main() {
    s := "test"
    var sr poke.Scanner
    sr = poke.TxtScanner{s}
    sr.Scan()
}

txt_scanner.go：

package poke

type TxtScanner struct {
    Txt string
}

func newTxtScanner(host string) Scanner {
    return TxtScanner{host}
}

func (tcpcs TxtScanner) Scan() *ScanResult {
    // do stuff
    result := ScanResult{}
    return &result
}

types.go：

package poke

type ScanResult struct {
}

scanner.go：

package poke

type Scanner interface {
    Scan() *ScanResult
}

在Go中实现一个接口

1 个答案: