Safe Haskell	Safe
Language	Haskell2010

Text.LambdaOptions.Parseable

Description

Class used for parsing command-line options.

Synopsis

class Parseable a where
- parse :: [String] -> (Maybe a, Int)
maybeParse :: (String -> Maybe a) -> [String] -> (Maybe a, Int)
boundedParse :: (String -> BoundedRead a) -> [String] -> (Maybe a, Int)
repeatedParse :: Parseable a => Int -> [String] -> (Maybe [a], Int)
simpleParse :: (String -> Maybe a) -> [String] -> (Maybe a, Int)

Documentation

class Parseable a where Source #

Class describing parseable values. Much like the Read class.

Methods

parse :: [String] -> (Maybe a, Int) Source #

Given a sequence of strings, parse returns Nothing and the number of strings (not characters) consumed if the parse failed. Otherwise, parse returns Just the parsed value and the number of strings consumed.

Element-wise, an entire string must be parsed in the sequence to be considered a successful parse.

Instances

Parseable Char Source #	Parses a single character string.
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe Char, Int) Source #
Parseable Double Source #	Parses an `Double` using its `Read` instance.
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe Double, Int) Source #
Parseable Float Source #	Parses a `Float` using its `Read` instance.
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe Float, Int) Source #
Parseable Int Source #	Parses an `Int` using its `ReadBounded` instance.
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe Int, Int) Source #
Parseable Integer Source #	Parses an `Integer` using its `Read` instance.
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe Integer, Int) Source #
Parseable Word Source #	Parses a `Word` using its `ReadBounded` instance.
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe Word, Int) Source #
Parseable () Source #	Always succeeds and never consumes any input.
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe (), Int) Source #
Parseable SomeSymbol Source #	Opaque identity parser for `SymbolVal`. Ex: > parse [""] == (Just (SomeSymbol (Proxy :: Proxy "")), 1) > parse ["foo"] == (Just (SomeSymbol (Proxy :: Proxy "foo")), 1) > parse [] == (Nothing, 0)
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe SomeSymbol, Int) Source #
Parseable SomeNat Source #	Parses a `SomeNat` by matching its corresponding shown `natVal`. Ex: > parse ["0"] == (Just (Proxy :: SomeNat (Proxy 0)), 1) > parse ["13"] == (Just (Proxy :: SomeNat (Proxy 13)), 1) > parse ["00"] == Nothing > parse ["0xFF"] == Nothing
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe SomeNat, Int) Source #
Parseable String Source #	Identity parser. parse [""] == (Just "", 1) parse ["foo"] == (Just "foo", 1) parse [] == (Nothing, 0)
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe String, Int) Source #
Parseable a => Parseable (Maybe a) Source #	Greedily parses a single argument or no argument. Never fails.
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe (Maybe a), Int) Source #
Parseable a => Parseable (List a) Source #	Greedily parses arguments item-wise. Never fails. Example: `parse (words "5 67 NaN") == (Just (List [5,67]), 2)`
Instance details Defined in Text.LambdaOptions.List Methods parse :: [String] -> (Maybe (List a), Int) Source #
(Parseable a, Parseable b) => Parseable (a, b) Source #	Parses two values sequentially.
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe (a, b), Int) Source #
KnownNat n => Parseable (Proxy n) Source #	Parses a `KnownNat` by matching its corresponding shown `natVal`. Ex: > parse ["0"] == (Just (Proxy :: Proxy 0), 1) > parse ["13"] == (Just (Proxy :: Proxy 13), 1) > parse ["00"] == Nothing > parse ["0xFF"] == Nothing
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe (Proxy n), Int) Source #
KnownSymbol s => Parseable (Proxy s) Source #	Parses the exact string given by `symbolVal`. Ex: > parse [""] == (Just (Proxy :: Proxy ""), 1) > parse ["foo"] == (Just (Proxy :: Proxy "foo"), 1) > parse ["foo"] == (Nothing :: Maybe (Proxy :: "bar"), 0) > parse [] == (Nothing, 0)
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe (Proxy s), Int) Source #
(Parseable a, Parseable b, Parseable c) => Parseable (a, b, c) Source #	Parses three values sequentially.
Instance details Defined in Text.LambdaOptions.Parseable Methods parse :: [String] -> (Maybe (a, b, c), Int) Source #
(ReadBoolWord w, ReadBoolLetter l, ReadBoolNumber n, BoolCasingVal c) => Parseable (Booly w l n c) Source #	Parses a `Booly` using `readBooly`.
Instance details Defined in Text.LambdaOptions.Bool Methods parse :: [String] -> (Maybe (Booly w l n c), Int) Source #

maybeParse :: (String -> Maybe a) -> [String] -> (Maybe a, Int) Source #

Turns a parser of a single string into a parser suitable for a Parseable instance.

Useful for implementing a Parseable for a type with a Read instance by supplying readMaybe to this function.

Note: The string is not tokenized in any way before being passed into the input parser.

boundedParse :: (String -> BoundedRead a) -> [String] -> (Maybe a, Int) Source #

Turns a parser of a single string into a parser suitable for a Parseable instance.

Useful for implementing a Parseable for a type with a ReadBounded instance by supplying readBounded to this function.

Note: The string is not tokenized in any way before being passed into the input parser.

repeatedParse :: Parseable a => Int -> [String] -> (Maybe [a], Int) Source #

Repeatedly applies parse the given number of times, accumulating the results.

Useful for implementing new parsers.

Example:

data Point = Point Float Float Float

instance Parseable Point where
  parse args = case repeatedParse 3 args of
    (Just [x,y,z], n) -> (Just (Point x y z), n)`
    (Nothing, n) -> (Nothing, n)

simpleParse :: (String -> Maybe a) -> [String] -> (Maybe a, Int) Source #

Deprecated: Use maybeParse instead.