package main
 
import (
    "fmt"
    "regexp"
    "strconv"
)
 
// Version 表示一個(gè)語(yǔ)義化的版本號(hào)
type Version struct {
    Major int // 主版本號(hào)
    Minor int // 次版本號(hào)
    Patch int // 修訂號(hào)
}
 
// NewVersion 解析版本字符串并返回 Version 結(jié)構(gòu)體
func NewVersion(v string) (*Version, error) {
    // 使用正則表達(dá)式匹配語(yǔ)義化版本號(hào)
    re := regexp.MustCompile(`^(\d+)\.(\d+)\.(\d+)$`)
    matches := re.FindStringSubmatch(v)
    if matches == nil {
        return nil, fmt.Errorf("invalid version format")
    }
    // 將字符串轉(zhuǎn)換為整數(shù)
    major, _ := strconv.Atoi(matches[1])
    minor, _ := strconv.Atoi(matches[2])
    patch, _ := strconv.Atoi(matches[3])
    return &Version{major, minor, patch}, nil
}

// CompareTo 比較兩個(gè)版本號(hào)
// 返回值 -1 表示 v 小于 other
// 返回值 0 表示 v 等于 other
// 返回值 1 表示 v 大于 other
func (v *Version) CompareTo(other *Version) int {
    if v.Major != other.Major {
        return compareInts(v.Major, other.Major)
    }
    if v.Minor != other.Minor {
        return compareInts(v.Minor, other.Minor)
    }
    return compareInts(v.Patch, other.Patch)
}
 
// compareInts 是一個(gè)輔助函數(shù)，用于比較兩個(gè)整數(shù)
func compareInts(a, b int) int {
    if a < b {
        return -1
    } else if a > b {
        return 1
    }
    return 0
}

func main() {
    v1, err := NewVersion("1.2.3")
    if err != nil {
        fmt.Println(err)
        return
    }
    v2, err := NewVersion("1.2.4")
    if err != nil {
        fmt.Println(err)
        return
    }
 
    comparison := v1.CompareTo(v2)
    switch comparison {
    case -1:
        fmt.Printf("%s is less than %s\n", v1, v2)
    case 0:
        fmt.Printf("%s is equal to %s\n", v1, v2)
    case 1:
        fmt.Printf("%s is greater than %s\n", v1, v2)
    }
}
 
// String 方法使得 Version 結(jié)構(gòu)體可以被打印輸出
func (v Version) String() string {
    return fmt.Sprintf("%d.%d.%d", v.Major, v.Minor, v.Patch)
}

package main
 
import (
    "fmt"
    "github.com/hashicorp/go-version"
    "sort"
)
 
func main() {
    // 比較大小
    v1, err := version.NewVersion("1.2")
    if err != nil {
        return
    }
    v2, err := version.NewVersion("1.5+metadata")
    if err != nil {
        return
    }
    if v1.LessThan(v2) {
        fmt.Printf("%s is less than %s \n", v1, v2)
    }
 
    // 判斷范圍
    v3, err := version.NewVersion("1.2")
    if err != nil {
        return
    }
    constraints, err := version.NewConstraint(">= 1.0, < 1.4")
    if constraints.Check(v3) {
        fmt.Printf("%s satisfies constraints %s \n", v1, constraints)
    }
 
    // 排序
    versionsRaw := []string{"1.1", "0.7.1", "1.4-beta", "1.4", "2"}
    versions := make([]*version.Version, len(versionsRaw))
    for i, raw := range versionsRaw {
        v, _ := version.NewVersion(raw)
        versions[i] = v
    }
    // After this, the versions are properly sorted
    sort.Sort(version.Collection(versions))
    fmt.Println(versions)
}