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Merge pull request #357 from kevin-cantwell/parse-usage-placeholders

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Parses usage placeholders via back quotes. Resolves #333
This commit is contained in:
Jesse Szwedko 2016-04-25 19:45:59 -07:00
commit 7528b17cc6
3 changed files with 77 additions and 24 deletions
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21
README.md
View File

@ -195,6 +195,27 @@ app.Action = func(c *cli.Context) {
See full list of flags at http://godoc.org/github.com/codegangsta/cli
#### Placeholder Values
Sometimes it's useful to specify a flag's value within the usage string itself. Such placeholders are
indicated with back quotes.
For example this:
```go
cli.StringFlag{
Name: "config, c",
Usage: "Load configuration from `FILE`",
}
```
Will result in help output like:
```
--config FILE, -c FILE Load configuration from FILE
```
Note that only the first placeholder is used. Subsequent back-quoted words will be left as-is.
#### Alternate Names
You can set alternate (or short) names for flags by providing a comma-delimited list for the `Name`. e.g.

52
flag.go
View File

@ -74,7 +74,8 @@ type GenericFlag struct {
// help text to the user (uses the String() method of the generic flag to show
// the value)
func (f GenericFlag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s %v\t%v", prefixedNames(f.Name), f.FormatValueHelp(), f.Usage))
placeholder, usage := unquoteUsage(f.Usage)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s %v\t%v", prefixedNames(f.Name, placeholder), f.FormatValueHelp(), usage))
}
func (f GenericFlag) FormatValueHelp() string {
@ -143,7 +144,8 @@ type StringSliceFlag struct {
func (f StringSliceFlag) String() string {
firstName := strings.Trim(strings.Split(f.Name, ",")[0], " ")
pref := prefixFor(firstName)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s [%v]\t%v", prefixedNames(f.Name), pref+firstName+" option "+pref+firstName+" option", f.Usage))
placeholder, usage := unquoteUsage(f.Usage)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s [%v]\t%v", prefixedNames(f.Name, placeholder), pref+firstName+" option "+pref+firstName+" option", usage))
}
// Apply populates the flag given the flag set and environment
@ -212,7 +214,8 @@ type IntSliceFlag struct {
func (f IntSliceFlag) String() string {
firstName := strings.Trim(strings.Split(f.Name, ",")[0], " ")
pref := prefixFor(firstName)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s [%v]\t%v", prefixedNames(f.Name), pref+firstName+" option "+pref+firstName+" option", f.Usage))
placeholder, usage := unquoteUsage(f.Usage)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s [%v]\t%v", prefixedNames(f.Name, placeholder), pref+firstName+" option "+pref+firstName+" option", usage))
}
// Apply populates the flag given the flag set and environment
@ -257,7 +260,8 @@ type BoolFlag struct {
// String returns a readable representation of this value (for usage defaults)
func (f BoolFlag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s\t%v", prefixedNames(f.Name), f.Usage))
placeholder, usage := unquoteUsage(f.Usage)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s\t%v", prefixedNames(f.Name, placeholder), usage))
}
// Apply populates the flag given the flag set and environment
@ -300,7 +304,8 @@ type BoolTFlag struct {
// String returns a readable representation of this value (for usage defaults)
func (f BoolTFlag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s\t%v", prefixedNames(f.Name), f.Usage))
placeholder, usage := unquoteUsage(f.Usage)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s\t%v", prefixedNames(f.Name, placeholder), usage))
}
// Apply populates the flag given the flag set and environment
@ -343,7 +348,8 @@ type StringFlag struct {
// String returns the usage
func (f StringFlag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s %v\t%v", prefixedNames(f.Name), f.FormatValueHelp(), f.Usage))
placeholder, usage := unquoteUsage(f.Usage)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s %v\t%v", prefixedNames(f.Name, placeholder), f.FormatValueHelp(), usage))
}
func (f StringFlag) FormatValueHelp() string {
@ -391,7 +397,8 @@ type IntFlag struct {
// String returns the usage
func (f IntFlag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s \"%v\"\t%v", prefixedNames(f.Name), f.Value, f.Usage))
placeholder, usage := unquoteUsage(f.Usage)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s \"%v\"\t%v", prefixedNames(f.Name, placeholder), f.Value, usage))
}
// Apply populates the flag given the flag set and environment
@ -434,7 +441,8 @@ type DurationFlag struct {
// String returns a readable representation of this value (for usage defaults)
func (f DurationFlag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s \"%v\"\t%v", prefixedNames(f.Name), f.Value, f.Usage))
placeholder, usage := unquoteUsage(f.Usage)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s \"%v\"\t%v", prefixedNames(f.Name, placeholder), f.Value, usage))
}
// Apply populates the flag given the flag set and environment
@ -477,7 +485,8 @@ type Float64Flag struct {
// String returns the usage
func (f Float64Flag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s \"%v\"\t%v", prefixedNames(f.Name), f.Value, f.Usage))
placeholder, usage := unquoteUsage(f.Usage)
return withEnvHint(f.EnvVar, fmt.Sprintf("%s \"%v\"\t%v", prefixedNames(f.Name, placeholder), f.Value, usage))
}
// Apply populates the flag given the flag set and environment
@ -517,16 +526,37 @@ func prefixFor(name string) (prefix string) {
return
}
func prefixedNames(fullName string) (prefixed string) {
// Returns the placeholder, if any, and the unquoted usage string.
func unquoteUsage(usage string) (string, string) {
for i := 0; i < len(usage); i++ {
if usage[i] == '`' {
for j := i + 1; j < len(usage); j++ {
if usage[j] == '`' {
name := usage[i+1 : j]
usage = usage[:i] + name + usage[j+1:]
return name, usage
}
}
break
}
}
return "", usage
}
func prefixedNames(fullName, placeholder string) string {
var prefixed string
parts := strings.Split(fullName, ",")
for i, name := range parts {
name = strings.Trim(name, " ")
prefixed += prefixFor(name) + name
if placeholder != "" {
prefixed += " " + placeholder
}
if i < len(parts)-1 {
prefixed += ", "
}
}
return
return prefixed
}
func withEnvHint(envVar, str string) string {

14
flag_test.go
View File

@ -4,9 +4,9 @@ import (
"fmt"
"os"
"reflect"
"runtime"
"strings"
"testing"
"runtime"
)
var boolFlagTests = []struct {
@ -31,19 +31,21 @@ func TestBoolFlagHelpOutput(t *testing.T) {
var stringFlagTests = []struct {
name string
usage string
value string
expected string
}{
{"help", "", "--help \t"},
{"h", "", "-h \t"},
{"h", "", "-h \t"},
{"test", "Something", "--test \"Something\"\t"},
{"help", "", "", "--help \t"},
{"h", "", "", "-h \t"},
{"h", "", "", "-h \t"},
{"test", "", "Something", "--test \"Something\"\t"},
{"config,c", "Load configuration from `FILE`", "", "--config FILE, -c FILE \tLoad configuration from FILE"},
}
func TestStringFlagHelpOutput(t *testing.T) {
for _, test := range stringFlagTests {
flag := StringFlag{Name: test.name, Value: test.value}
flag := StringFlag{Name: test.name, Usage: test.usage, Value: test.value}
output := flag.String()
if output != test.expected {