nutcracker

README

nutcracker

a simple shell parsing and execution engine

Features

nutcracker can parse a subset of shell commands as detailed below:

Environment variables

echo $HOME ${ENVVAR:-default value}

Command substitution

echo $(cat file.txt)

String variable interpolation

"$(echo hello) $HOME ${ENVVAR:-default value}"

Documentation

Index

• Constants
• type Cmd
  • func Parse(shellcmd string) (*Cmd, error)
  • func (c Cmd) Exec(env Env) error
• type Env
• type EnvFunc
• type Executor
  • func NewExecutor() Executor
• type Node

Constants

const (
	ErrUnclosedStrI = internalError(iota)
	ErrUnclosedStrL
	ErrUnclosedParen
	ErrUnclosedBrace
	ErrInvalidEscape
	ErrInvalidCloseParen
	ErrInvalidCloseBrace
	ErrInvalidVar
	ErrInvalidArgMode
	ErrInvalidExec
)

Types

type Cmd

type Cmd struct {
	// contains filtered or unexported fields
}

func Parse

func Parse(shellcmd string) (*Cmd, error)

func (Cmd) Exec

func (c Cmd) Exec(env Env) error

type Env

type Env struct {
	Envvar  []string
	Envfunc EnvFunc
	Stdin   io.Reader
	Stdout  io.Writer
	Stderr  io.Writer
	Ex      Executor
}

type EnvFunc

type EnvFunc func(string) string

type Executor

type Executor interface {
	Exec(args []string, env Env) error
}

func NewExecutor

func NewExecutor() Executor

type Node

type Node interface {
	Value(env Env) (string, error)
}