optparse-applicative-0.15.1.0: Utilities and combinators for parsing command line options

Safe HaskellSafe
LanguageHaskell98

Options.Applicative.Common

Contents

Synopsis

Option parsers

A Parser is composed of a list of options. Several kinds of options are supported:

  • Flags: simple no-argument options. When a flag is encountered on the command line, its value is returned.
  • Options: options with an argument. An option can define a reader, which converts its argument from String to the desired value, or throws a parse error if the argument does not validate correctly.
  • Arguments: positional arguments, validated in the same way as option arguments.
  • Commands. A command defines a completely independent sub-parser. When a command is encountered, the whole command line is passed to the corresponding parser.

data Parser a Source #

A Parser a is an option parser returning a value of type a.

Instances
Functor Parser Source # 
Instance details

Defined in Options.Applicative.Types

Methods

fmap :: (a -> b) -> Parser a -> Parser b

(<$) :: a -> Parser b -> Parser a

Applicative Parser Source # 
Instance details

Defined in Options.Applicative.Types

Methods

pure :: a -> Parser a

(<*>) :: Parser (a -> b) -> Parser a -> Parser b

liftA2 :: (a -> b -> c) -> Parser a -> Parser b -> Parser c

(*>) :: Parser a -> Parser b -> Parser b

(<*) :: Parser a -> Parser b -> Parser a

Alternative Parser Source # 
Instance details

Defined in Options.Applicative.Types

Methods

empty :: Parser a

(<|>) :: Parser a -> Parser a -> Parser a

some :: Parser a -> Parser [a]

many :: Parser a -> Parser [a]

liftOpt :: Option a -> Parser a Source #

Create a parser composed of a single option.

showOption :: OptName -> String Source #

Program descriptions

data ParserInfo a Source #

A full description for a runnable Parser for a program.

Constructors

ParserInfo 

Fields

Instances
Functor ParserInfo Source # 
Instance details

Defined in Options.Applicative.Types

Methods

fmap :: (a -> b) -> ParserInfo a -> ParserInfo b

(<$) :: a -> ParserInfo b -> ParserInfo a

data ParserPrefs Source #

Global preferences for a top-level Parser.

Constructors

ParserPrefs 

Fields

  • prefMultiSuffix :: String

    metavar suffix for multiple options

  • prefDisambiguate :: Bool

    automatically disambiguate abbreviations (default: False)

  • prefShowHelpOnError :: Bool

    always show help text on parse errors (default: False)

  • prefShowHelpOnEmpty :: Bool

    show the help text for a command or subcommand if it fails with no input (default: False)

  • prefBacktrack :: Backtracking

    backtrack to parent parser when a subcommand fails (default: Backtrack)

  • prefColumns :: Int

    number of columns in the terminal, used to format the help page (default: 80)

  • prefHelpLongEquals :: Bool

    when displaying long names in usage and help, use an '=' sign for long names, rather than a single space (default: False)

Instances
Eq ParserPrefs Source # 
Instance details

Defined in Options.Applicative.Types

Methods

(==) :: ParserPrefs -> ParserPrefs -> Bool

(/=) :: ParserPrefs -> ParserPrefs -> Bool

Show ParserPrefs Source # 
Instance details

Defined in Options.Applicative.Types

Methods

showsPrec :: Int -> ParserPrefs -> ShowS

show :: ParserPrefs -> String

showList :: [ParserPrefs] -> ShowS

Running parsers

runParser :: MonadP m => ArgPolicy -> IsCmdStart -> Parser a -> Args -> m (a, Args) Source #

Apply a Parser to a command line, and return a result and leftover arguments. This function returns an error if any parsing error occurs, or if any options are missing and don't have a default value.

evalParser :: Parser a -> Maybe a Source #

The default value of a Parser. This function returns an error if any of the options don't have a default value.

Low-level utilities

mapParser :: (forall x. OptHelpInfo -> Option x -> b) -> Parser a -> [b] Source #

Map a polymorphic function over all the options of a parser, and collect the results in a list.

treeMapParser :: (forall x. OptHelpInfo -> Option x -> b) -> Parser a -> OptTree b Source #

Like mapParser, but collect the results in a tree structure.