Project Organization and Style

Package Names

Go package names are short, lowercase identifiers that make selectors read naturally.

package naming Good package names avoid stutter and casing surprises at call sites.

Package Names

packageName
package_names.go
Replay: real traced execution (multi-file project)
package main

import "fmt"

func isLowerIdentifier(name string) bool {
	if name == "" {
		return false
	}
	for _, ch := range name {
		if ch < 'a' || ch > 'z' {
			return false
		}
	}
	return true
}

func main() {
	var packageName = "cache"
	lowercase := isLowerIdentifier(packageName)
	selector := packageName + ".Store"
	style := "review"
	if lowercase {
		style = "ok"
	}

	fmt.Println("package=", packageName)
	fmt.Println("selector=", selector)
	fmt.Println("lowercase=", lowercase)
	fmt.Println("style=", style)
}

package main

import "fmt"

func isLowerIdentifier(name string) bool {
	if name == "" {
		return false
	}
	for _, ch := range name {
		if ch < 'a' || ch > 'z' {
			return false
		}
	}
	return true
}

func main() {
	var packageName = "CacheStore"
	lowercase := isLowerIdentifier(packageName)
	selector := packageName + ".Store"
	style := "review"
	if lowercase {
		style = "ok"
	}

	fmt.Println("package=", packageName)
	fmt.Println("selector=", selector)
	fmt.Println("lowercase=", lowercase)
	fmt.Println("style=", style)
}

package main

import "fmt"

func isLowerIdentifier(name string) bool {
	if name == "" {
		return false
	}
	for _, ch := range name {
		if ch < 'a' || ch > 'z' {
			return false
		}
	}
	return true
}

func main() {
	var packageName = "cacheutil"
	lowercase := isLowerIdentifier(packageName)
	selector := packageName + ".Store"
	style := "review"
	if lowercase {
		style = "ok"
	}

	fmt.Println("package=", packageName)
	fmt.Println("selector=", selector)
	fmt.Println("lowercase=", lowercase)
	fmt.Println("style=", style)
}

  1. packageName ← "cache"

    17func main() {18  var packageName→ "cache" = "cache" //@packageName="CacheStore", "cacheutil"19  lowercase := isLowerIdentifier(packageName"cache")20  selector := packageName + ".Store"

  2. func isLowerIdentifier(name string) bool

    5func isLowerIdentifier(name"cache" string) bool {6  if name == "" {

  3. for _, ch := range name

    pass 1 of 5
    8}9for _, ch99 := range name"cache" {10  if ch < 'a' || ch > 'z' {
    All 5 passes — pass 1 is the card above
    passch
    199
    297
    399
    4104
    5101

  4. return true

    13  }14  return true15}

  5. lowercase ← true, selector ← "cache.Store", style ← "review"

    18var packageName = "cache" //@packageName="CacheStore", "cacheutil"19lowercase→ true := isLowerIdentifier(packageName"cache")20selector→ "cache.Store" := packageName"cache" + ".Store"21style→ "review" := "review"22if lowercase {

  6. style ← "ok"

    21style := "review"22if lowercasetrue {23  style→ "ok" = "ok"24}

  7. fmt.Println("package=", packageName)

    26  fmt.Println("package=", packageName"cache")27  fmt.Println("selector=", selector"cache.Store")28  fmt.Println("lowercase=", lowercasetrue)29  fmt.Println("style=", style"ok")30}
    outputpackage= cache
selector= cache.Store
lowercase= true
style= ok

  1. packageName ← "CacheStore"

    17func main() {18  var packageName→ "CacheStore" = "CacheStore"19  lowercase := isLowerIdentifier(packageName"CacheStore")20  selector := packageName + ".Store"

  2. func isLowerIdentifier(name string) bool

    5func isLowerIdentifier(name"CacheStore" string) bool {6  if name == "" {

  3. for _, ch := range name

    8}9for _, ch67 := range name"CacheStore" {10  if ch < 'a' || ch > 'z' {

  4. if ch < 'a' || ch > 'z'

    9for _, ch := range name {10  if ch67 < 'a' || ch > 'z' {11    return false12  }

  5. lowercase ← false, selector ← "CacheStore.Store", style ← "review"

    18  var packageName = "CacheStore"19  lowercase→ false := isLowerIdentifier(packageName"CacheStore")20  selector→ "CacheStore.Store" := packageName"CacheStore" + ".Store"21  style→ "review" := "review"22  if lowercase {23    style = "ok"24  }2526  fmt.Println("package=", packageName"CacheStore")27  fmt.Println("selector=", selector"CacheStore.Store")28  fmt.Println("lowercase=", lowercasefalse)29  fmt.Println("style=", style"review")30}
    outputpackage= CacheStore
selector= CacheStore.Store
lowercase= false
style= review

  1. packageName ← "cacheutil"

    17func main() {18  var packageName→ "cacheutil" = "cacheutil"19  lowercase := isLowerIdentifier(packageName"cacheutil")20  selector := packageName + ".Store"

  2. func isLowerIdentifier(name string) bool

    5func isLowerIdentifier(name"cacheutil" string) bool {6  if name == "" {

  3. for _, ch := range name

    pass 1 of 9
    8}9for _, ch99 := range name"cacheutil" {10  if ch < 'a' || ch > 'z' {
    All 9 passes — pass 1 is the card above
    passch
    199
    297
    399
    4104
    5101
    6117
    7116
    8105
    9108

  4. return true

    13  }14  return true15}

  5. lowercase ← true, selector ← "cacheutil.Store", style ← "review"

    18var packageName = "cacheutil"19lowercase→ true := isLowerIdentifier(packageName"cacheutil")20selector→ "cacheutil.Store" := packageName"cacheutil" + ".Store"21style→ "review" := "review"22if lowercase {

  6. style ← "ok"

    21style := "review"22if lowercasetrue {23  style→ "ok" = "ok"24}

  7. fmt.Println("package=", packageName)

    26  fmt.Println("package=", packageName"cacheutil")27  fmt.Println("selector=", selector"cacheutil.Store")28  fmt.Println("lowercase=", lowercasetrue)29  fmt.Println("style=", style"ok")30}
    outputpackage= cacheutil
selector= cacheutil.Store
lowercase= true
style= ok