optparse-applicative-0.14.0.0: 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 # 

Methods

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

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

Applicative Parser Source # 

Methods

pure :: a -> Parser a #

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

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

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

Alternative Parser Source # 

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.

Program descriptions

data ParserInfo a Source #

A full description for a runnable Parser for a program.

Constructors

ParserInfo 

Fields

Instances

Functor ParserInfo Source # 

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

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.