Data.Registry.Options.Parser

Main module for creating option parsers

Documentation

data Parser (s :: Symbol) a

A Parser is responsible for parsing a value of type a for to be used as "s" where s is a Symbol For example "s" can be the name of a field, force in a data type

A Parser generally returns all the original lexemes values minus the option name and value just parsed This is a bit different for positional arguments for example where the whole list of lexemes values is kept

Constructors

Parser

Fields

• parserHelp :: Help
• parseLexed :: Lexemes -> Either Text (a, Lexemes)

Instances

Alternative (Parser s)

Defined in Data.Registry.Options.Parser

Methods

empty :: Parser s a

(<|>) :: Parser s a -> Parser s a -> Parser s a

some :: Parser s a -> Parser s [a]

many :: Parser s a -> Parser s [a]

Applicative (Parser s)

Defined in Data.Registry.Options.Parser

Methods

pure :: a -> Parser s a

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

liftA2 :: (a -> b -> c) -> Parser s a -> Parser s b -> Parser s c

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

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

Functor (Parser s)

Defined in Data.Registry.Options.Parser

Methods

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

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

data Positional

This data type indicates if an argument must be parsed at a specific position This changes the parsing since positional arguments do not consume lexemes

Constructors

Positional

NonPositional

Instances

Show Positional

Defined in Data.Registry.Options.Parser

Methods

showsPrec :: Int -> Positional -> ShowS

show :: Positional -> String

showList :: [Positional] -> ShowS

Eq Positional

Defined in Data.Registry.Options.Parser

Methods

(==) :: Positional -> Positional -> Bool

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

unitParser :: Parser s ()

This parser does not consume anything but always succeeds. It is a unit for the *> operator

addParserHelp :: Help -> Parser s a -> Parser s a

Add some help description to a Parser

setParserHelp :: Help -> Parser s a -> Parser s a

Set some help description on a Parser

getOptionNames :: Parser s a -> [Text]

Retrieve all the option names for this parser by extracting the help and collecting option names for the top level command and the subcommands

type Command = "Command"

The Command type can be used to create parsers which are not given a specific role

coerceParser :: Parser s a -> Parser t a

All parsers can be used to parse a command

parseArgs :: Parser s a -> [Text] -> Either Text a

Command line arguments can be parsed with a specific and either return an error if there is nothing to parse, or if the parse is not successful

parse :: Parser s a -> Text -> Either Text a

Shortcut for parsing some text by splitting it on spaces

parserOf :: forall a b. (ApplyVariadic (Parser Command) a b, Typeable a, Typeable b) => a -> Typed b

Create a Parser a for a given constructor of type a by using the Applicative instance of a Parser

maybeParser :: Parser s a -> Parser s (Maybe a)

Make a Parser for a Maybe type. If the original parser does not succeeds this parser returns Nothing and does not consume anything

listParser :: Parser s a -> Parser s [a]

Make a Parser for a List type. This works by repeatedly applying the original parser to inputs (and appending results) until the parser fails in which case [] is returned

list1Parser :: Parser s a -> Parser s [a]

Make a Parser for a List type where at least one value is expected to be parsed

nonEmptyParser :: Parser s a -> Parser s (NonEmpty a)

Make a Parser for a NonEmpty type (this means that least one value is expected to be parsed)

parseField :: forall s a. (KnownSymbol s, Typeable a, Show a) => FieldConfiguration -> Positional -> Text -> OptionDescriptionUpdates -> DefaultValue s a -> ActiveValue s a -> Decoder a -> Parser s a

Create a Parser for command-line field given: - fieldOptions to derive longshortmetavar names from a field name - a field name. If it is missing, then we can only parse arguments - a field type. We use the type to make a METAVAR - additional OptionDescription to either override the previous values, or to add the field help - an optional default value for the field: the value to use if the field is missing - an optional active value for the field: the value to use if the field is present - a Decoder to read the value as text

parseWith :: forall s a. (KnownSymbol s, Typeable a, Show a) => OptionDescriptionUpdates -> DefaultValue s a -> ActiveValue s a -> Decoder a -> Parser s a

Create a parser for a given field given: - its name(s) - an optional default value for the field: the value to use if the field is missing - an optional active value for the field: the value to use if the field is present - a Decoder to read the value as text

takeOptionValue :: [Text] -> Lexemes -> Maybe (Text, Maybe Text, Lexemes)

Find a value for a given option name return Nothing if the name is not found If the name is found return - Nothing if there is no value - the first value for that name if there is is one and remove the value associated to the flag if there aren't any values left associated to a flag, remove it

takeArgumentValue :: Lexemes -> Maybe (Text, Lexemes)

Take the first argument value available and remove it from the list of lexed arguments

getSymbol :: forall s. KnownSymbol s => Text

Return the textual representation of a symbol (this is a fully qualified string)

showType :: forall a. Typeable a => Text

Return the type of a value as Text