README
¶
import "github.com/mkmueller/option"
Package option is a command line option and argument parser that will populate a given struct, argument slice, or both. Unix-style keys as well as gnu-style long keywords are accepted. Command line keys are automatically generated based on each struct field name and data type. optional help text may be supplied using a tag for each struct field. Additionally, option keys may be customized using the struct field tags.
All other command line arguments that are not defined in your option struct will be interpreted as regular arguments and appended to your argument slice. The number of arguments accepted by the parser may be limited by simply making your argument slice with a maximum cap value. If the user exceeds this cap, an error will be returned. Alternatively, a fixed array may be defined. This will cause the parser to expect an exact number of aguments, or return an error.
Documentation
¶
Overview ¶
Package option is a command line option and argument parser that will populate a given struct, argument slice, or both. Unix-style keys as well as gnu-style long keywords are accepted. Command line keys are automatically generated based on each struct field name and data type. optional help text may be supplied using a tag for each struct field. Additionally, option keys may be customized using the struct field tags.
All other command line arguments that are not defined in your option struct will be interpreted as regular arguments and appended to your argument slice. The number of arguments accepted by the parser may be limited by simply making your argument slice with a maximum cap value. If the user exceeds this cap, an error will be returned. Alternatively, a fixed array may be defined. This will cause the parser to expect an exact number of aguments, or return an error.
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Option ¶
type Option struct {
// contains filtered or unexported fields
}
func New ¶
Create a new option object struct.
Example ¶
The following example shows a simple option definition
package main
import (
"fmt"
"github.com/mkmueller/option"
"log"
"os"
)
func main() {
// Set command line arguments for testing
oldArgs := os.Args
os.Args = []string{"mycommand", "-a", "42", "-b", "-q", "What?", "Towel"}
// Define options
var opt struct {
Answer int
Babel bool
Question string
}
// Define argument slice
var args []string
// Create a new command line object
op, err := option.New(&opt, &args)
if err != nil {
log.Println(err)
return
}
fmt.Printf("%s\n", op.Cmd())
fmt.Printf("%d\n", opt.Answer)
fmt.Printf("%v\n", opt.Babel)
fmt.Printf("%s\n", opt.Question)
fmt.Printf("%v %v\n", len(args), args[0])
os.Args = oldArgs
}
Output: mycommand 42 true What? 1 Towel
func (*Option) Help ¶
func (o *Option) Help()
Print the entire help text for this option configuration.
Example ¶
The following example shows a simple option definition
package main
import (
"github.com/mkmueller/option"
"log"
"os"
)
func main() {
// Set command line arguments for testing
oldArgs := os.Args
os.Args = []string{"mycommand"}
// Define options
var opt struct {
Answer int
Babel bool
Question string
}
// Define argument slice
var args []string
// Create a new command line object
op, err := option.New(&opt, &args)
if err != nil {
log.Println(err)
return
}
// Print help text
op.Help()
os.Args = oldArgs
}
Output: SYNOPSIS mycommand [OPTIONS] [string]... OPTIONS -a int, --answer=int -b, --babel -q string, --question=string
Example (Tags) ¶
Defining struct tags will allow you to add help text or optionally change key names.
package main
import (
"github.com/mkmueller/option"
"log"
"os"
)
func main() {
// Set command line arguments for testing
oldArgs := os.Args
os.Args = []string{"mycommand"}
// Define options with tags with key name changes
var opt struct {
Answer int `I:Supply your answer`
Babel bool `translate:Enable bable fish translator`
Question string `a:ask:question:Ask the ultimate question`
}
// Create a new command line object
op, err := option.New(&opt)
if err != nil {
log.Println(err)
return
}
// Print help text
op.Help()
os.Args = oldArgs
}
Output: SYNOPSIS mycommand [OPTIONS] OPTIONS -I int Supply your answer --translate Enable bable fish translator -a question, --ask=question Ask the ultimate question
func (*Option) HelpString ¶
Return the entire help text for this option configuration as a string.
func (*Option) Section ¶
Add section heading and paragraphs to your help text
Example ¶
Add sections to help text
package main
import (
"github.com/mkmueller/option"
"log"
"os"
)
func main() {
// Set command line arguments for testing
oldArgs := os.Args
os.Args = []string{"mycommand"}
// Define option struct with tags
var opt struct {
Answer int `I:Supply your answer`
Babel bool `translate:Enable bable fish translator`
Question string `a:ask:question:Ask the ultimate question`
}
// Define argument slice
var args []string
// Create a new command line object
op, err := option.New(&opt, &args)
if err != nil {
log.Println(err)
return
}
// Name and description sections will be placed at top of help text
op.Section("NAME", "Hitchhiker Ipsum")
op.Section("DESCRIPTION", "Lorem Ipsum Hitchhiker simply generating "+
"synthesized improbability drive closes world sector satisfaction "+
"secretively reasoning ship launch physicists accident with science.")
// Section with option keyword will be inserted before the option
op.Section("translate:BABLE FISH TRANSLATOR", "Babel Fish patterns exist else "+
"communication decode centers which killed brainwave "+
"kidneys prove logic combining best refused.")
// Normal section will be placed after option list
op.Section("NOTES", "Stolen whim bizarrely speech have evolved small zebra "+
"supplied coincidence Deep Thought chosen history nothing purely "+
"we'll prove.")
// Print help text
op.Help()
os.Args = oldArgs
}
Output: NAME Hitchhiker Ipsum SYNOPSIS mycommand [OPTIONS] [string]... DESCRIPTION Lorem Ipsum Hitchhiker simply generating synthesized improbability drive closes world sector satisfaction secretively reasoning ship launch physicists accident with science. OPTIONS -I int Supply your answer BABLE FISH TRANSLATOR Babel Fish patterns exist else communication decode centers which killed brainwave kidneys prove logic combining best refused. --translate Enable bable fish translator -a question, --ask=question Ask the ultimate question NOTES Stolen whim bizarrely speech have evolved small zebra supplied coincidence Deep Thought chosen history nothing purely we'll prove.
Source Files