| Safe Haskell | Safe |
|---|---|
| Language | Haskell98 |
Options.Applicative.Builder
- subparser :: Mod CommandFields a -> Parser a
- strArgument :: Mod ArgumentFields String -> Parser String
- argument :: ReadM a -> Mod ArgumentFields a -> Parser a
- flag :: a -> a -> Mod FlagFields a -> Parser a
- flag' :: a -> Mod FlagFields a -> Parser a
- switch :: Mod FlagFields Bool -> Parser Bool
- abortOption :: ParseError -> Mod OptionFields (a -> a) -> Parser (a -> a)
- infoOption :: String -> Mod OptionFields (a -> a) -> Parser (a -> a)
- strOption :: Mod OptionFields String -> Parser String
- option :: ReadM a -> Mod OptionFields a -> Parser a
- nullOption :: ReadM a -> Mod OptionFields a -> Parser a
- short :: HasName f => Char -> Mod f a
- long :: HasName f => String -> Mod f a
- help :: String -> Mod f a
- helpDoc :: Maybe Doc -> Mod f a
- value :: HasValue f => a -> Mod f a
- showDefaultWith :: (a -> String) -> Mod f a
- showDefault :: Show a => Mod f a
- metavar :: HasMetavar f => String -> Mod f a
- eitherReader :: (String -> Either String a) -> ReadM a
- noArgError :: ParseError -> Mod OptionFields a
- data ParseError
- hidden :: Mod f a
- internal :: Mod f a
- command :: String -> ParserInfo a -> Mod CommandFields a
- completeWith :: HasCompleter f => [String] -> Mod f a
- action :: HasCompleter f => String -> Mod f a
- completer :: HasCompleter f => Completer -> Mod f a
- idm :: Monoid m => m
- (<>) :: Monoid m => m -> m -> m
- mappend :: Monoid a => a -> a -> a
- auto :: Read a => ReadM a
- str :: ReadM String
- disabled :: ReadM a
- readerAbort :: ParseError -> ReadM a
- readerError :: String -> ReadM a
- data InfoMod a
- fullDesc :: InfoMod a
- briefDesc :: InfoMod a
- header :: String -> InfoMod a
- headerDoc :: Maybe Doc -> InfoMod a
- footer :: String -> InfoMod a
- footerDoc :: Maybe Doc -> InfoMod a
- progDesc :: String -> InfoMod a
- progDescDoc :: Maybe Doc -> InfoMod a
- failureCode :: Int -> InfoMod a
- noIntersperse :: InfoMod a
- info :: Parser a -> InfoMod a -> ParserInfo a
- data PrefsMod
- multiSuffix :: String -> PrefsMod
- disambiguate :: PrefsMod
- showHelpOnError :: PrefsMod
- noBacktrack :: PrefsMod
- columns :: Int -> PrefsMod
- prefs :: PrefsMod -> ParserPrefs
- defaultPrefs :: ParserPrefs
- data Mod f a
- data ReadM a
- data OptionFields a
- data FlagFields a
- data ArgumentFields a
- data CommandFields a
Parser builders
This module contains utility functions and combinators to create parsers for individual options.
Each parser builder takes an option modifier. A modifier can be created by
composing the basic modifiers provided by this module using the Monoid
operations mempty and mappend, or their aliases idm and <>.
For example:
out = strOption
( long "output"
<> short 'o'
<> metavar "FILENAME" )creates a parser for an option called "output".
subparser :: Mod CommandFields a -> Parser a
Builder for a command parser. The command modifier can be used to
specify individual commands.
strArgument :: Mod ArgumentFields String -> Parser String
Builder for a String argument.
argument :: ReadM a -> Mod ArgumentFields a -> Parser a
Builder for an argument parser.
Arguments
| :: a | default value |
| -> a | active value |
| -> Mod FlagFields a | option modifier |
| -> Parser a |
Builder for a flag parser.
A flag that switches from a "default value" to an "active value" when
encountered. For a simple boolean value, use switch instead.
Arguments
| :: a | active value |
| -> Mod FlagFields a | option modifier |
| -> Parser a |
Builder for a flag parser without a default value.
Same as flag, but with no default value. In particular, this flag will
never parse successfully by itself.
It still makes sense to use it as part of a composite parser. For example
length <$> many (flag' () (short 't'))
is a parser that counts the number of "-t" arguments on the command line.
abortOption :: ParseError -> Mod OptionFields (a -> a) -> Parser (a -> a)
An option that always fails.
When this option is encountered, the option parser immediately aborts with
the given parse error. If you simply want to output a message, use
infoOption instead.
infoOption :: String -> Mod OptionFields (a -> a) -> Parser (a -> a)
An option that always fails and displays a message.
strOption :: Mod OptionFields String -> Parser String
Builder for an option taking a String argument.
option :: ReadM a -> Mod OptionFields a -> Parser a
Builder for an option using the given reader.
nullOption :: ReadM a -> Mod OptionFields a -> Parser a
Modifiers
value :: HasValue f => a -> Mod f a
Specify a default value for an option.
Note: Because this modifier means the parser will never fail,
do not use it with combinators such as some or many, as
these combinators continue until a failure occurs.
Careless use will thus result in a hang.
showDefaultWith :: (a -> String) -> Mod f a
Specify a function to show the default value for an option.
showDefault :: Show a => Mod f a
Show the default value for this option using its Show instance.
metavar :: HasMetavar f => String -> Mod f a
Specify a metavariable for the argument.
Metavariables have no effect on the actual parser, and only serve to specify the symbolic name for an argument to be displayed in the help text.
eitherReader :: (String -> Either String a) -> ReadM a
Convert a function in the Either monad to a reader.
noArgError :: ParseError -> Mod OptionFields a
Specify the error to display when no argument is provided to this option.
data ParseError
Constructors
| ErrorMsg String | |
| InfoMsg String | |
| ShowHelpText | |
| UnknownError | |
| MissingError (OptTree (Chunk Doc)) |
Instances
command :: String -> ParserInfo a -> Mod CommandFields a
Add a command to a subparser option.
completeWith :: HasCompleter f => [String] -> Mod f a
Add a list of possible completion values.
action :: HasCompleter f => String -> Mod f a
Add a bash completion action. Common actions include file and
directory. See
http://www.gnu.org/software/bash/manual/html_node/Programmable-Completion-Builtins.html#Programmable-Completion-Builtins
for a complete list.
completer :: HasCompleter f => Completer -> Mod f a
Add a completer to an argument.
A completer is a function String -> IO String which, given a partial argument, returns all possible completions for that argument.
Readers
A collection of basic Option readers.
readerAbort :: ParseError -> ReadM a
Abort option reader by exiting with a ParseError.
readerError :: String -> ReadM a
Abort option reader by exiting with an error message.
Builder for ParserInfo
progDescDoc :: Maybe Doc -> InfoMod a
Specify a short program description as a Doc
value.
failureCode :: Int -> InfoMod a
Specify an exit code if a parse error occurs.
noIntersperse :: InfoMod a
Disable parsing of regular options after arguments
info :: Parser a -> InfoMod a -> ParserInfo a
Create a ParserInfo given a Parser and a modifier.
Builder for ParserPrefs
multiSuffix :: String -> PrefsMod
prefs :: PrefsMod -> ParserPrefs
Default preferences.
Types
data Mod f a
An option modifier.
Option modifiers are values that represent a modification of the properties of an option.
The type parameter a is the return type of the option, while f is a
record containing its properties (e.g. OptionFields for regular options,
FlagFields for flags, etc...).
An option modifier consists of 3 elements:
- A field modifier, of the form
f a -> f a. These are essentially (compositions of) setters for some of the properties supported byf. - An optional default value and function to display it.
- A property modifier, of the form
OptProperties -> OptProperties. This is just like the field modifier, but for properties applicable to any option.
Modifiers are instances of Monoid, and can be composed as such.
You rarely need to deal with modifiers directly, as most of the times it is
sufficient to pass them to builders (such as strOption or flag) to
create options (see Builder).
data OptionFields a
data FlagFields a
Instances
data ArgumentFields a
data CommandFields a
Instances