cliche

README

cliche: Simple CLIs for Go

//go:generate TODO(christian)
type Hello struct {
    Name string
}

func (h *Hello) Run(ctx context.Context, out io.Writer) error {
    fmt.Fprintf(out, "Hello, %v!", h.Name)
}

After running go generate and go build, there is now a hello command:

$ hello -name=World
Hello, World!
...

//go:generate TODO(christian)
type Hello struct {
    Name string `cli:"arg"`
}

func (h *Hello) Run(ctx context.Context, out io.Writer) error {
    fmt.Fprintf(out, "Hello, %v!", h.Name)
}

$ hello World
Hello, World!
...

//go:generate TODO(christian)
type Hello struct {
    Name string `cli:"default:World"`
}

func (h *Hello) Run(ctx context.Context, out io.Writer) error {
    fmt.Fprintf(out, "Hello, %v!", h.Name)
}

$ hello World
Hello, World!
...

//go:generate TODO(christian)
type Hello struct {
    Name string `cli:"flag;default:World"`
}

func (h *Hello) Run(ctx context.Context, out io.Writer) error {
    fmt.Fprintf(out, "Hello, %v!", h.Name)
}

$ hello World
Hello, World!
...

Documentation

Overview

Package cliche provides types and functions for declaratively creating CLIs in Go.

Index

• type CommandInputMetadata
• type CommandMetadata
  • func FromFile(typeName, file string) *CommandMetadata
  • func (meta *CommandMetadata) Compile(n ast.Node) bool
• type IO
• type Tag

Types

type CommandInputMetadata

type CommandInputMetadata struct {
	FieldName string
	Tag       Tag
	Doc       string
	Type      string
}

CommandInputMetadata contains details about how a Command's inputs should be mapped to the struct members of the implementing type.

type CommandMetadata

type CommandMetadata struct {
	// Name of the command to be generated. This defaults to the name of the
	// package, unless overridden.
	Name string

	// Package name from which the  Command is sourced.
	Package string

	// Type name of the  Command implementation.
	Type string

	// Help output for the  Command. This will be displayed along with usage
	// information on the command line. By default, sourced from doc comment for
	// the package in which the wrapped Command will live.
	Help string

	// Description of the command. Should be short and human readable. By
	// default, sourced from the doc comment on the wrapped  Command type.
	Description string

	// Inputs describe the handling of struct fields on the wrapped Command
	// implementation as inputs on the command line. The inputs are derived from
	// struct tags, when set.
	Inputs []CommandInputMetadata
	// contains filtered or unexported fields
}

CommandMetadata compiles details about how the Command type should be wrapped from the AST describing it. This type is used to execute a Go template, to generate the resulting Go source file.

func FromFile

func FromFile(typeName, file string) *CommandMetadata

FromFile attempts to find a type typeName and generate command metadata from file, returning nil on failure.

func (*CommandMetadata) Compile

func (meta *CommandMetadata) Compile(n ast.Node) bool

Compile the AST of a Go file into command metadata. Designed to be used as an argument to ast.Inspect.

type IO

type IO struct {
	In  io.Reader
	Out io.Writer
	Err io.Writer
}

IO wraps the I/O targets for a facile command.

type Tag

type Tag string