Cabal-3.12.1.0: A framework for packaging Haskell software

Copyright | Duncan Coutts 2007
License | BSD3
Maintainer | cabal-devel@haskell.org
Portability | non-portable (ExistentialQuantification)
Safe Haskell | None
Language | Haskell2010

Distribution.Simple.Command

Contents

- Command interface
  - Constructing commands
  - Associating actions with commands
  - Building lists of commands
  - Running commands
- Option Fields
  - Constructing Option Fields
  - Liftings & Projections
- Option Descriptions
  - OptDescr `smart` constructors

Description

This is to do with command line handling. The Cabal command line is organised into a number of named sub-commands (much like darcs). The `CommandUI` abstraction represents one of these sub-commands, with a name, description, a set of flags. Commands can be associated with actions and run. It handles some common stuff automatically, like the `--help` and command line completion flags. It is designed to allow other tools make derived commands. This feature is used heavily in `cabal-install`.

Synopsis

- data CommandUI flags = CommandUI {
  - commandName :: String
  - commandSynopsis :: String
  - commandUsage :: String -> String
  - commandDescription :: Maybe (String -> String)
  - commandNotes :: Maybe (String -> String)
  - commandDefaultFlags :: flags
  - commandOptions :: ShowOrParseArgs -> [OptionField flags]
  }
- commandShowOptions :: CommandUI flags -> flags -> [String]
- data CommandParse flags
  - = CommandHelp (String -> String)
  - | CommandList [String]
  - | CommandErrors [String]
  - | CommandReadyToGo flags
- commandParseArgs :: CommandUI flags -> Bool -> [String] -> CommandParse (flags -> flags, [String])
- getNormalCommandDescriptions :: [Command action] -> [(String, String)]
- helpCommandUI :: CommandUI ()
- data ShowOrParseArgs
  - = ShowArgs
  - | ParseArgs
- usageDefault :: String -> String -> String
- usageAlternatives :: String -> [String] -> String -> String
- mkCommandUI :: String -> String -> [String] -> flags -> (ShowOrParseArgs -> [OptionField flags]) -> CommandUI flags
- hiddenCommand :: Command action -> Command action
- data Command action
- commandAddAction :: CommandUI flags -> (flags -> [String] -> action) -> Command action
- noExtraFlags :: [String] -> IO ()
- data CommandType
  - = NormalCommand
  - | HiddenCommand
- data CommandSpec action = CommandSpec (CommandUI flags) (CommandUI flags -> Command action) CommandType
- commandFromSpec :: CommandSpec a -> Command a
- commandsRun :: CommandUI a -> [Command action] -> [String] -> IO (CommandParse (a, CommandParse action))
- commandsRunWithFallback :: CommandUI a -> [Command action] -> ([Command action] -> String -> [String] -> IO (CommandParse action)) -> [String] -> IO (CommandParse (a, CommandParse action))
- defaultCommandFallback :: [Command action] -> String -> [String] -> IO (CommandParse action)
- data OptionField a = OptionField {
  - optionName :: Name
  - optionDescr :: [OptDescr a]
  }
- type Name = String
- option :: SFlags -> LFlags -> Description -> get -> set -> MkOptDescr get set a -> OptionField a
- multiOption :: Name -> get -> set -> [get -> set -> OptDescr a] -> OptionField a
- liftOption :: (b -> a) -> (a -> b -> b) -> OptionField a -> OptionField b
- liftOptionL :: ALens' b a -> OptionField a -> OptionField b
- data OptDescr a
  - = ReqArg Description OptFlags ArgPlaceHolder (ReadE (a -> a)) (a -> [String])
  - | OptArg Description OptFlags ArgPlaceHolder (ReadE (a -> a)) (String, a -> a) (a -> [Maybe String])
  - | ChoiceOpt [(Description, OptFlags, a -> a, a -> Bool)]
  - | BoolOpt Description OptFlags OptFlags (Bool -> a -> a) (a -> Maybe Bool)
- type Description = String
- type SFlags = [Char]
- type LFlags = [String]
- type OptFlags = (SFlags, LFlags)
- type ArgPlaceHolder = String
- type MkOptDescr get set a = SFlags -> LFlags -> Description -> get -> set -> OptDescr a
- reqArg :: Monoid b => ArgPlaceHolder -> ReadE b -> (b -> [String]) -> MkOptDescr (a -> b) (b -> a -> a) a
- reqArg' :: Monoid b => ArgPlaceHolder -> (String -> b) -> (b -> [String]) -> MkOptDescr (a -> b) (b -> a -> a) a
- optArg :: Monoid b => ArgPlaceHolder -> ReadE b -> (String, b) -> (b -> [Maybe String]) -> MkOptDescr (a -> b) (b -> a -> a) a
- optArg' :: Monoid b => ArgPlaceHolder -> (Maybe String -> b) -> (b -> [Maybe String]) -> MkOptDescr (a -> b) (b -> a -> a) a
- optArgDef' :: Monoid b => ArgPlaceHolder -> (String, Maybe String -> b) -> (b -> [Maybe String]) -> MkOptDescr (a -> b) (b -> a -> a) a
- noArg :: Eq b => b -> MkOptDescr (a -> b) (b -> a -> a) a
- boolOpt :: (b -> Maybe Bool) -> (Bool -> b) -> SFlags -> SFlags -> MkOptDescr (a -> b) (b -> a -> a) a
- boolOpt' :: (b -> Maybe Bool) -> (Bool -> b) -> OptFlags -> OptFlags -> MkOptDescr (a -> b) (b -> a -> a) a
- choiceOpt :: Eq b => [(b, OptFlags, Description)] -> MkOptDescr (a -> b) (b -> a -> a) a
- choiceOptFromEnum :: (Bounded b, Enum b, Show b, Eq b) => MkOptDescr (a -> b) (b -> a -> a) a

# Command interface

data CommandUI flags Source #

Constructors

CommandUI |

Fields

- commandName :: String

  The name of the command as it would be entered on the command line. For example `"build"`.

- commandSynopsis :: String

  A short, one line description of the command to use in help texts.

- commandUsage :: String -> String

  A function that maps a program name to a usage summary for this command.

- commandDescription :: Maybe (String -> String)

  Additional explanation of the command to use in help texts.

- commandNotes :: Maybe (String -> String)

  Post-Usage notes and examples in help texts

- commandDefaultFlags :: flags

  Initial / empty flags

- commandOptions :: ShowOrParseArgs -> [OptionField flags]

  All the Option fields for this command

commandShowOptions :: CommandUI flags -> flags -> [String] Source #

Show flags in the standard long option command line format

data CommandParse flags Source #

Constructors

CommandHelp (String -> String) |
CommandList [String] |
CommandErrors [String] |
CommandReadyToGo flags |

#### Instances

Instances details

Functor CommandParse Source # |
Instance details Defined in Distribution.Simple.Command Methods fmap :: (a -> b) -> CommandParse a -> CommandParse b # (<$) :: a -> CommandParse b -> CommandParse a #

commandParseArgs Source #

Arguments

:: CommandUI flags |
-> Bool | Is the command a global or subcommand?
-> [String] |
-> CommandParse (flags -> flags, [String]) |

Parse a bunch of command line arguments

getNormalCommandDescriptions :: [Command action] -> [(String, String)] Source #

Helper function for creating globalCommand description

helpCommandUI :: CommandUI () Source #

## Constructing commands

data ShowOrParseArgs Source #

Constructors

ShowArgs |
ParseArgs |

usageDefault :: String -> String -> String Source #

Default "usage" documentation text for commands.

usageAlternatives :: String -> [String] -> String -> String Source #

Create "usage" documentation from a list of parameter configurations.

mkCommandUI Source #

Arguments

:: String | name
-> String | synopsis
-> [String] | usage alternatives
-> flags | initial/empty flags
-> (ShowOrParseArgs -> [OptionField flags]) | options
-> CommandUI flags |

Make a Command from standard `GetOpt` options.

hiddenCommand :: Command action -> Command action Source #

Mark command as hidden. Hidden commands don't show up in the 'progname help' or 'progname --help' output.

## Associating actions with commands

data Command action Source #

commandAddAction :: CommandUI flags -> (flags -> [String] -> action) -> Command action Source #

noExtraFlags :: [String] -> IO () Source #

Utility function, many commands do not accept additional flags. This action fails with a helpful error message if the user supplies any extra.

## Building lists of commands

data CommandType Source #

Constructors

NormalCommand |
HiddenCommand |

data CommandSpec action Source #

wraps a `CommandUI` together with a function that turns it into a `Command`. By hiding the type of flags for the UI allows construction of a list of all UIs at the top level of the program. That list can then be used for generation of manual page as well as for executing the selected command.

Constructors

CommandSpec (CommandUI flags) (CommandUI flags -> Command action) CommandType |

commandFromSpec :: CommandSpec a -> Command a Source #

## Running commands

commandsRun :: CommandUI a -> [Command action] -> [String] -> IO (CommandParse (a, CommandParse action)) Source #

commandsRunWithFallback :: CommandUI a -> [Command action] -> ([Command action] -> String -> [String] -> IO (CommandParse action)) -> [String] -> IO (CommandParse (a, CommandParse action)) Source #

defaultCommandFallback :: [Command action] -> String -> [String] -> IO (CommandParse action) Source #

# Option Fields

data OptionField a Source #

We usually have a data type for storing configuration values, where every field stores a configuration option, and the user sets the value either via command line flags or a configuration file. An individual OptionField models such a field, and we usually build a list of options associated to a configuration data type.

Constructors

OptionField |

Fields

- optionName :: Name
- optionDescr :: [OptDescr a]

type Name = String Source #

## Constructing Option Fields

option :: SFlags -> LFlags -> Description -> get -> set -> MkOptDescr get set a -> OptionField a Source #

Create an option taking a single OptDescr. No explicit Name is given for the Option, the name is the first LFlag given.

Example: ``option` sf lf d get set` * `sf`: Short option name, for example: `['d']`. No hyphen permitted. * `lf`: Long option name, for example: `["debug"]`. No hyphens permitted. * `d`: Description of the option, shown to the user in help messages. * `get`: Get the current value of the flag. * `set`: Set the value of the flag. Gets the current value of the flag as a parameter.

multiOption Source #

Arguments

:: Name |
-> get |
-> set |
-> [get -> set -> OptDescr a] | MkOptDescr constructors partially applied to flags and description.
-> OptionField a |

Create an option taking several OptDescrs. You will have to give the flags and description individually to the OptDescr constructor.

## Liftings & Projections

liftOption :: (b -> a) -> (a -> b -> b) -> OptionField a -> OptionField b Source #

liftOptionL :: ALens' b a -> OptionField a -> OptionField b Source #

Since: Cabal-3.4.0.0

# Option Descriptions

data OptDescr a Source #

An OptionField takes one or more OptDescrs, describing the command line interface for the field.

Constructors

ReqArg Description OptFlags ArgPlaceHolder (ReadE (a -> a)) (a -> [String]) |
OptArg Description OptFlags ArgPlaceHolder (ReadE (a -> a)) (String, a -> a) (a -> [Maybe String]) |
ChoiceOpt [(Description, OptFlags, a -> a, a -> Bool)] |
BoolOpt Description OptFlags OptFlags (Bool -> a -> a) (a -> Maybe Bool) |

type Description = String Source #

type SFlags = [Char] Source #

Short command line option strings

type LFlags = [String] Source #

Long command line option strings

type OptFlags = (SFlags, LFlags) Source #

type ArgPlaceHolder = String Source #

## OptDescr `smart` constructors

type MkOptDescr get set a = SFlags -> LFlags -> Description -> get -> set -> OptDescr a Source #

reqArg :: Monoid b => ArgPlaceHolder -> ReadE b -> (b -> [String]) -> MkOptDescr (a -> b) (b -> a -> a) a Source #

Create a string-valued command line interface. Usually called in the context of `option` or `multiOption`.

Example: ``reqArg` ad mkflag showflag`

- `ad`: Placeholder shown to the user, e.g. `FILES` if files are expected parameters.
- `mkflag`: How to parse the argument into the option.
- `showflag`: If parsing goes wrong, display a useful error message to the user.

reqArg' :: Monoid b => ArgPlaceHolder -> (String -> b) -> (b -> [String]) -> MkOptDescr (a -> b) (b -> a -> a) a Source #

(String -> a) variant of "reqArg"

optArg :: Monoid b => ArgPlaceHolder -> ReadE b -> (String, b) -> (b -> [Maybe String]) -> MkOptDescr (a -> b) (b -> a -> a) a Source #

Create a string-valued command line interface with a default value.

optArg' :: Monoid b => ArgPlaceHolder -> (Maybe String -> b) -> (b -> [Maybe String]) -> MkOptDescr (a -> b) (b -> a -> a) a Source #

(String -> a) variant of "optArg"

optArgDef' :: Monoid b => ArgPlaceHolder -> (String, Maybe String -> b) -> (b -> [Maybe String]) -> MkOptDescr (a -> b) (b -> a -> a) a Source #

noArg :: Eq b => b -> MkOptDescr (a -> b) (b -> a -> a) a Source #

boolOpt :: (b -> Maybe Bool) -> (Bool -> b) -> SFlags -> SFlags -> MkOptDescr (a -> b) (b -> a -> a) a Source #

boolOpt' :: (b -> Maybe Bool) -> (Bool -> b) -> OptFlags -> OptFlags -> MkOptDescr (a -> b) (b -> a -> a) a Source #

choiceOpt :: Eq b => [(b, OptFlags, Description)] -> MkOptDescr (a -> b) (b -> a -> a) a Source #

create a Choice option

choiceOptFromEnum :: (Bounded b, Enum b, Show b, Eq b) => MkOptDescr (a -> b) (b -> a -> a) a Source #

create a Choice option out of an enumeration type. As long flags, the Show output is used. As short flags, the first character which does not conflict with a previous one is used.