Gerald Kaszuba
48 lines
1.5 KiB
Markdown
48 lines
1.5 KiB
Markdown
# Kong is a command-line parser for Go [](https://circleci.com/gh/alecthomas/kong)
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It parses a command-line into a struct. eg.
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```go
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package main
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import "github.com/alecthomas/kong"
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var CLI struct {
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Rm struct {
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Force bool `kong:"help='Force removal.'"`
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Recursive bool `kong:"help='Recursively remove files.'"`
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Paths []string `kong:"help='Paths to remove.',type='path'"`
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} `kong:"help='Remove files.'"`
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Ls struct {
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Paths []string `kong:"help='Paths to list.',type='path'"`
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} `kong:"help='List paths.'"`
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}
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func main() {
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kong.Parse(&CLI)
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}
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```
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## Decoders
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Command-line arguments are mapped to Go values via the Decoder interface:
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```go
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// A Decoder knows how to decode text into a Go value.
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type Decoder interface {
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// Decode scan into target.
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//
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// "ctx" contains context about the value being decoded that may be useful
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// to some decoders.
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Decode(ctx *DecoderContext, scan *Scanner, target reflect.Value) error
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}
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```
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All builtin Go types (as well as a bunch of useful stdlib types like `time.Time`) have decoders registered by default. Decoders for custom types can be added using `kong.RegisterDecoder(decoder)`. Decoders are mapped from fields in three ways:
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1. By registering a `kong.NamedDecoder` and using the key `type='<name>'`.
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2. By registering a `kong.KindDecoder` with a `reflect.Kind`.
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3. By registering a `kong.TypeDecoder` with a `reflect.Type`.
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