Distribution.Simple.Command

Cabal-1.6.0.3: A framework for packaging Haskell software

Portability	portable
Maintainer	cabal-devel@haskell.org

Contents

Command interface

Constructing commands
Associating actions with 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)

commandDefaultFlags :: flags

commandOptions :: ShowOrParseArgs -> [OptionField flags]

}

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

data ShowOrParseArgs

= ShowArgs

| ParseArgs

makeCommand :: String -> String -> Maybe (String -> String) -> flags -> (ShowOrParseArgs -> [OptionField flags]) -> CommandUI flags

data Command action

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

noExtraFlags :: [String] -> IO ()

data CommandParse flags

= CommandHelp (String -> String)

| CommandList [String]

| CommandErrors [String]

| CommandReadyToGo flags

commandsRun :: CommandUI a -> [Command action] -> [String] -> CommandParse (a, 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

viewAsFieldDescr :: OptionField a -> FieldDescr a

data OptDescr a

= ReqArg Description OptFlags ArgPlaceHolder (ReadE (a -> a)) (a -> [String])

| OptArg Description OptFlags ArgPlaceHolder (ReadE (a -> a)) (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 -> 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

noArg :: (Eq b, Monoid 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

Constructors

CommandUI

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	The useage line summary for this command
commandDescription :: Maybe (String -> String)	Additional explanation of the command to use in help texts.
commandDefaultFlags :: flags	Initial / empty flags
commandOptions :: ShowOrParseArgs -> [OptionField flags]	All the Option fields for this command

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

Show flags in the standard long option command line format

Constructing commands

data ShowOrParseArgs

Constructors

ShowArgs
ParseArgs

makeCommand

::
=> String	name
-> String	short description
-> Maybe (String -> String)	long description
-> flags	initial/empty flags
-> ShowOrParseArgs -> [OptionField flags]	options
-> CommandUI flags
Make a Command from standard GetOpt options.

Associating actions with commands

data Command action

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

noExtraFlags :: [String] -> IO ()

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

Running commands

data CommandParse flags

Constructors

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

Instances

Functor CommandParse

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

Option Fields

data OptionField a

We usually have a datatype 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 datatype.

Constructors

OptionField

optionName :: Name
optionDescr :: [OptDescr a]

type Name = String

Constructing Option Fields

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

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

multiOption

::
=> 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

viewAsFieldDescr :: OptionField a -> FieldDescr a

to view as a FieldDescr, we sort the list of interfaces (Req > Bool > Choice > Opt) and consider only the first one.

Option Descriptions

data OptDescr a

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)) (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]

Short command line option strings

type LFlags = [String]

Long command line option strings

type OptFlags = (SFlags, LFlags)

type ArgPlaceHolder = String

OptDescr smart constructors

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

Create a string-valued command line interface.

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

(String -> a) variant of reqArg

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

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

(String -> a) variant of optArg

noArg :: (Eq b, Monoid 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

create a Choice option

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

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.

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