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116 lines
3.8 KiB
Markdown
116 lines
3.8 KiB
Markdown
docopt-go
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=========
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[](https://travis-ci.org/docopt/docopt.go)
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[](https://coveralls.io/github/docopt/docopt.go)
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[](https://godoc.org/github.com/docopt/docopt.go)
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An implementation of [docopt](http://docopt.org/) in the [Go](http://golang.org/) programming language.
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**docopt** helps you create *beautiful* command-line interfaces easily:
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```go
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package main
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import (
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"fmt"
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"github.com/docopt/docopt-go"
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)
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func main() {
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usage := `Naval Fate.
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Usage:
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naval_fate ship new <name>...
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naval_fate ship <name> move <x> <y> [--speed=<kn>]
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naval_fate ship shoot <x> <y>
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naval_fate mine (set|remove) <x> <y> [--moored|--drifting]
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naval_fate -h | --help
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naval_fate --version
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Options:
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-h --help Show this screen.
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--version Show version.
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--speed=<kn> Speed in knots [default: 10].
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--moored Moored (anchored) mine.
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--drifting Drifting mine.`
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arguments, _ := docopt.ParseDoc(usage)
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fmt.Println(arguments)
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}
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```
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**docopt** parses command-line arguments based on a help message. Don't write parser code: a good help message already has all the necessary information in it.
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## Installation
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⚠ Use the alias "docopt-go". To use docopt in your Go code:
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```go
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import "github.com/docopt/docopt-go"
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```
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To install docopt in your `$GOPATH`:
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```console
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$ go get github.com/docopt/docopt-go
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```
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## API
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Given a conventional command-line help message, docopt processes the arguments. See https://github.com/docopt/docopt#help-message-format for a description of the help message format.
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This package exposes three different APIs, depending on the level of control required. The first, simplest way to parse your docopt usage is to just call:
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```go
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docopt.ParseDoc(usage)
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```
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This will use `os.Args[1:]` as the argv slice, and use the default parser options. If you want to provide your own version string and args, then use:
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```go
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docopt.ParseArgs(usage, argv, "1.2.3")
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```
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If the last parameter (version) is a non-empty string, it will be printed when `--version` is given in the argv slice. Finally, we can instantiate our own `docopt.Parser` which gives us control over how things like help messages are printed and whether to exit after displaying usage messages, etc.
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```go
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parser := &docopt.Parser{
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HelpHandler: docopt.PrintHelpOnly,
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OptionsFirst: true,
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}
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opts, err := parser.ParseArgs(usage, argv, "")
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```
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In particular, setting your own custom `HelpHandler` function makes unit testing your own docs with example command line invocations much more enjoyable.
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All three of these return a map of option names to the values parsed from argv, and an error or nil. You can get the values using the helpers, or just treat it as a regular map:
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```go
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flag, _ := opts.Bool("--flag")
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secs, _ := opts.Int("<seconds>")
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```
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Additionally, you can `Bind` these to a struct, assigning option values to the
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exported fields of that struct, all at once.
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```go
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var config struct {
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Command string `docopt:"<cmd>"`
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Tries int `docopt:"-n"`
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Force bool // Gets the value of --force
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}
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opts.Bind(&config)
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```
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More documentation is available at [godoc.org](https://godoc.org/github.com/docopt/docopt-go).
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## Unit Testing
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Unit testing your own usage docs is recommended, so you can be sure that for a given command line invocation, the expected options are set. An example of how to do this is [in the examples folder](examples/unit_test/unit_test.go).
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## Tests
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All tests from the Python version are implemented and passing at [Travis CI](https://travis-ci.org/docopt/docopt-go). New language-agnostic tests have been added to [test_golang.docopt](test_golang.docopt).
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To run tests for docopt-go, use `go test`.
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