ConfigParser

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

Documentation

type OptParser a = Ap Option a

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

parseConfig

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

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

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

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

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

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

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

Instances

Eq ConfParseError

Methods

(==) :: ConfParseError -> ConfParseError -> Bool

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

Ord ConfParseError

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

Methods

showsPrec :: Int -> ConfParseError -> ShowS

show :: ConfParseError -> String

showList :: [ConfParseError] -> ShowS

ShowErrorComponent ConfParseError

Methods

showErrorComponent :: ConfParseError -> String

type OParser = Parsec (CustomError ConfParseError) Text

data Option a

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

Instances

Functor Option

Methods

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

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

class OptionArgument a

Class for supported option types.

At the moment, orphan instances are not supported

Minimal complete definition

mkParser, printArgument

Instances

OptionArgument Int

Methods

mkParser :: (Text, OParser Int)

printArgument :: Int -> Text

OptionArgument Integer

Methods

mkParser :: (Text, OParser Integer)

printArgument :: Integer -> Text

OptionArgument String

Methods

mkParser :: (Text, OParser String)

printArgument :: String -> Text

OptionArgument Text

Methods

mkParser :: (Text, OParser Text)

printArgument :: Text -> Text