Moduleoptparse-applicative-0.18.1.0Haskell98

Options.Applicative.Common

Contents

Option parsers
Program descriptions
Running parsers
Low-level utilities

Synopsis

data Parser
value liftOpt
value showOption
data ParserInfo
data ParserPrefs
value runParserInfo
value runParserFully
value runParserStep
value runParser
value evalParser
value mapParser
value treeMapParser
value optionNames

Packageoptparse-applicative-0.18.1.0
Exports13
LanguageHaskell98
LicenceBSD-3-Clause
SourceTypes.hs

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.

datadata Parser a

Source#

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

Instances3Functor, Applicative, Alternative

Functor ParserDefined in optparse-applicative-0.18.1.0 · Options.Applicative.Types
Applicative ParserDefined in optparse-applicative-0.18.1.0 · Options.Applicative.Types
Alternative ParserDefined in optparse-applicative-0.18.1.0 · Options.Applicative.Types

valueliftOpt :: Option a -> Parser a

Source#

Create a parser composed of a single option.

valueshowOption :: OptName -> String

Program descriptions

datadata ParserInfo a

Source#

A full description for a runnable Parser for a program.

Constructors

ParserInfo
- infoParser :: Parser a
  the option parser for the program
- infoFullDesc :: Bool
  whether the help text should contain full documentation
- infoProgDesc :: Chunk Doc
  brief parser description
- infoHeader :: Chunk Doc
  header of the full parser description
- infoFooter :: Chunk Doc
  footer of the full parser description
- infoFailureCode :: Int
  exit code for a parser failure
- infoPolicy :: ArgPolicy
  allow regular options and flags to occur after arguments (default: InterspersePolicy)

Instances1Functor

Functor ParserInfoDefined in optparse-applicative-0.18.1.0 · Options.Applicative.Types

datadata ParserPrefs

Source#

Global preferences for a top-level Parser.

Constructors

ParserPrefs
- 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)
- prefHelpShowGlobal :: Bool
  when displaying subparsers' usage help, show parent options under a "global options" section (default: False)
- prefTabulateFill :: Int
  Indentation width for tables

Instances2Eq, Show

Eq ParserPrefsDefined in optparse-applicative-0.18.1.0 · Options.Applicative.Types
Show ParserPrefsDefined in optparse-applicative-0.18.1.0 · Options.Applicative.Types

Running parsers

valuerunParserInfo :: MonadP m => ParserInfo a -> Args -> m a

valuerunParserFully :: MonadP m => ArgPolicy -> Parser a -> Args -> m a

valuerunParserStep

:: MonadP m
=> ArgPolicy
-> Parser a
-> String
-> Args
-> m (Maybe (Parser a), Args)

valuerunParser

:: 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.

valueevalParser :: 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

valuemapParser

:: forall x. ArgumentReachability -> 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.

valuetreeMapParser

:: forall x. ArgumentReachability -> Option x -> b
-> Parser a
-> OptTree b

Source#

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

valueoptionNames :: OptReader a -> [OptName]