Safe Haskell	Safe-Inferred
Language	Haskell2010

ConfigParser

Description

Applicative config parser.

This parses config files in the style of optparse-applicative. It supports automatic generation of a default config both as datatype and in printed form.

Example:

data Config = Config
  { test :: Text
  , foobar :: Int
  }

confParser :: ConfParser Config
confParser = Config
         <$> option "test" "default value" "Help for test"
         <*> option "foobar" 42 "Help for foobar"

This parses a config file like the following:

# This is a comment
test = "something"
foobar = 23

Synopsis

type OptParser a = Ap Option a
parseConfig :: FilePath -> Text -> OptParser a -> Either CustomParseError a
parseConfigFile :: FilePath -> OptParser a -> IO (Either CustomParseError a)
option :: OptionArgument a => Text -> a -> Text -> OptParser a
customOption :: Text -> a -> Text -> Text -> Text -> OParser a -> OptParser a
parserDefault :: OptParser a -> a
parserExample :: OptParser a -> Text
data ConfParseError
type OParser = Parsec ConfParseError Text
data Option a
class OptionArgument a

Documentation

type OptParser a = Ap Option a Source #

The main parser type. Use option and the Applicative instance to create those.

parseConfig Source #

Arguments

:: FilePath	File path to use in error messages
-> Text	The input test
-> OptParser a	The parser to use
-> Either CustomParseError a

Parse a config file from a Text.

parseConfigFile Source #

Arguments

:: FilePath	Path to the file
-> OptParser a	The parser to use
-> IO (Either CustomParseError a)

Parse a config file from an actual file in the filesystem.

option Source #

Arguments

:: OptionArgument a
=> Text	The option name
-> a	The default value
-> Text	A help string for the option. Will be used by `parserExample` to create helpful comments.
-> OptParser a

OptParser that parses one option.

Can be combined with the Applicative instance for OptParser. See the module documentation for an example.

customOption Source #

Arguments

:: Text	The option name
-> a	The default Value
-> Text	A textual representation of the default value
-> Text	A help string for the option
-> Text	A description of the expected type such sas "string" or "integer"
-> OParser a	Parser for the option
-> OptParser a

parserDefault :: OptParser a -> a Source #

Returns the default value of a given parser.

This default value is computed from the default arguments of the option constructor. For the parser from the module description, the default value would be:

Config { test = "default value"
       , foobar :: 42
       }

parserExample :: OptParser a -> Text Source #

Generate the default config file.

This returns a valid config file, filled with the default values of every option and using the help string of these options as comments.

data ConfParseError Source #

Errors that can occur during parsing. Use the Show instance for printing.

Instances

Instances details

Eq ConfParseError Source #
Instance details Defined in ConfigParser Methods (==) :: ConfParseError -> ConfParseError -> Bool # (/=) :: ConfParseError -> ConfParseError -> Bool #
Ord ConfParseError Source #
Instance details Defined in ConfigParser Methods compare :: ConfParseError -> ConfParseError -> Ordering # (<) :: ConfParseError -> ConfParseError -> Bool # (<=) :: ConfParseError -> ConfParseError -> Bool # (>) :: ConfParseError -> ConfParseError -> Bool # (>=) :: ConfParseError -> ConfParseError -> Bool # max :: ConfParseError -> ConfParseError -> ConfParseError # min :: ConfParseError -> ConfParseError -> ConfParseError #
Show ConfParseError Source #
Instance details Defined in ConfigParser Methods showsPrec :: Int -> ConfParseError -> ShowS # show :: ConfParseError -> String # showList :: [ConfParseError] -> ShowS #
ShowErrorComponent ConfParseError Source #
Instance details Defined in ConfigParser Methods showErrorComponent :: ConfParseError -> String # errorComponentLen :: ConfParseError -> Int #

type OParser = Parsec ConfParseError Text Source #

data Option a Source #

An option in the config file. Use option as a smart constructor.

Instances

Instances details

Functor Option Source #
Instance details Defined in ConfigParser Methods fmap :: (a -> b) -> Option a -> Option b # (<$) :: a -> Option b -> Option a #

class OptionArgument a Source #

Class for supported option types.

At the moment, orphan instances are not supported

Minimal complete definition

mkParser, printArgument

Instances

Instances details

OptionArgument Int Source #
Instance details Defined in ConfigParser Methods mkParser :: (Text, OParser Int) printArgument :: Int -> Text
OptionArgument Integer Source #
Instance details Defined in ConfigParser Methods mkParser :: (Text, OParser Integer) printArgument :: Integer -> Text
OptionArgument String Source #
Instance details Defined in ConfigParser Methods mkParser :: (Text, OParser String) printArgument :: String -> Text
OptionArgument Text Source #
Instance details Defined in ConfigParser Methods mkParser :: (Text, OParser Text) printArgument :: Text -> Text