terraform/vendor/github.com/mitchellh/cli/command.go

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package cli
import (
"github.com/posener/complete"
)
const (
// RunResultHelp is a value that can be returned from Run to signal
// to the CLI to render the help output.
RunResultHelp = -18511
)
// A command is a runnable sub-command of a CLI.
type Command interface {
// Help should return long-form help text that includes the command-line
// usage, a brief few sentences explaining the function of the command,
// and the complete list of flags the command accepts.
Help() string
// Run should run the actual command with the given CLI instance and
// command-line arguments. It should return the exit status when it is
// finished.
//
// There are a handful of special exit codes this can return documented
// above that change behavior.
Run(args []string) int
// Synopsis should return a one-line, short synopsis of the command.
// This should be less than 50 characters ideally.
Synopsis() string
}
// CommandAutocomplete is an extension of Command that enables fine-grained
// autocompletion. Subcommand autocompletion will work even if this interface
// is not implemented. By implementing this interface, more advanced
// autocompletion is enabled.
type CommandAutocomplete interface {
// AutocompleteArgs returns the argument predictor for this command.
// If argument completion is not supported, this should return
// complete.PredictNothing.
AutocompleteArgs() complete.Predictor
// AutocompleteFlags returns a mapping of supported flags and autocomplete
// options for this command. The map key for the Flags map should be the
// complete flag such as "-foo" or "--foo".
AutocompleteFlags() complete.Flags
}
// CommandHelpTemplate is an extension of Command that also has a function
// for returning a template for the help rather than the help itself. In
// this scenario, both Help and HelpTemplate should be implemented.
//
// If CommandHelpTemplate isn't implemented, the Help is output as-is.
type CommandHelpTemplate interface {
// HelpTemplate is the template in text/template format to use for
// displaying the Help. The keys available are:
//
// * ".Help" - The help text itself
// * ".Subcommands"
//
HelpTemplate() string
}
// CommandFactory is a type of function that is a factory for commands.
// We need a factory because we may need to setup some state on the
// struct that implements the command itself.
type CommandFactory func() (Command, error)