{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE EmptyDataDecls #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
-- | This library auto-generates command-line parsers for data types using
-- Haskell's built-in support for generic programming. The best way to
-- understand how this library works is to walk through a few examples.
--
-- For example, suppose that you want to parse a record with named fields like
-- this:
--
-- > -- Example.hs
-- >
-- > {-# LANGUAGE DeriveGeneric #-}
-- > {-# LANGUAGE OverloadedStrings #-}
-- >
-- > import Options.Generic
-- >
-- > data Example = Example { foo :: Int, bar :: Double }
-- > deriving (Generic, Show)
-- >
-- > instance ParseRecord Example
-- >
-- > main = do
-- > x <- getRecord "Test program"
-- > print (x :: Example)
--
-- Named fields translate to flags which you can provide in any order:
--
-- > $ stack build optparse-generic
-- > $ stack runghc Example.hs -- --bar 2.5 --foo 1
-- > Example {foo = 1, bar = 2.5}
--
-- This also auto-generates @--help@ output:
--
-- > $ stack runghc Example.hs -- --help
-- > Test program
-- >
-- > Usage: Example.hs --foo INT --bar DOUBLE
-- >
-- > Available options:
-- > -h,--help Show this help text
--
-- You can also add help descriptions to each field, like this:
--
-- > {-# LANGUAGE DataKinds #-}
-- > {-# LANGUAGE DeriveGeneric #-}
-- > {-# LANGUAGE OverloadedStrings #-}
-- > {-# LANGUAGE TypeOperators #-}
-- >
-- > import Options.Generic
-- >
-- > data Example = Example
-- > { foo :: Int <?> "Documentation for the foo flag"
-- > , bar :: Double <?> "Documentation for the bar flag"
-- > } deriving (Generic, Show)
-- >
-- > instance ParseRecord Example
-- >
-- > main = do
-- > x <- getRecord "Test program"
-- > print (x :: Example)
--
-- ... which produces the following @--help@ output:
--
-- > $ stack runghc Example.hs -- --help
-- > Test program
-- >
-- > Usage: Example.hs --foo INT --bar DOUBLE
-- >
-- > Available options:
-- > -h,--help Show this help text
-- > --foo INT Documentation for the foo flag
-- > --bar DOUBLE Documentation for the bar flag
--
-- However, any fields you document will be wrapped in the `Helpful`
-- constructor:
--
-- > $ stack runghc Example.hs -- --foo 1 --bar 2.5
-- > Example {foo = Helpful {unHelpful = 1}, bar = Helpful {unHelpful = 2.5}}
--
-- To avoid this, while still being able to document your fields, you may
-- generalize the definition of your record with a parameter 'w', and use
-- 'unwrapRecord'.
--
-- > {-# LANGUAGE DataKinds #-}
-- > {-# LANGUAGE DeriveGeneric #-}
-- > {-# LANGUAGE FlexibleInstances #-} -- One more extension.
-- > {-# LANGUAGE OverloadedStrings #-}
-- > {-# LANGUAGE StandaloneDeriving #-} -- To derive Show
-- > {-# LANGUAGE TypeOperators #-}
-- >
-- > import Options.Generic
-- >
-- > data Example w = Example
-- > { foo :: w ::: Int <?> "Documentation for the foo flag"
-- > , bar :: w ::: Double <?> "Documentation for the bar flag"
-- > } deriving (Generic)
-- >
-- > instance ParseRecord (Example Wrapped)
-- > deriving instance Show (Example Unwrapped)
-- >
-- > main = do
-- > x <- unwrapRecord "Test program"
-- > print (x :: Example Unwrapped)
--
-- @Example Unwrapped@ is equivalent to a record type with simple fields:
--
-- > $ stack runghc Example.hs -- --foo 1 --bar 2.5
-- > Example {foo = 1, bar = 2.5}
--
-- You can also add default values to each `Read`able field, like this:
--
-- > {-# LANGUAGE DataKinds #-}
-- > {-# LANGUAGE DeriveGeneric #-}
-- > {-# LANGUAGE OverloadedStrings #-}
-- > {-# LANGUAGE TypeOperators #-}
-- >
-- > import Options.Generic
-- >
-- > data Example = Example
-- > { foo :: Int <!> "1"
-- > , bar :: String <!> "hello"
-- > } deriving (Generic, Show)
-- >
-- > instance ParseRecord Example
-- >
-- > main = do
-- > x <- getRecord "Test program"
-- > print (x :: Example)
--
-- Default values will work alongside help descriptions and unwrapping.
--
-- For the following examples I encourage you to test what @--help@ output they
-- generate.
--
-- This library will also do the right thing if the fields have no labels:
--
-- > data Example = Example Int Double deriving (Generic, Show)
--
-- Fields without labels translate into positional command-line arguments:
--
-- > $ stack runghc Example.hs -- 1 2.5
-- > Example 1 2.5
--
-- Certain types of fields are given special treatment, such as in this
-- example:
--
-- > data Example = Example
-- > { switch :: Bool
-- > , list :: [Int]
-- > , optional :: Maybe Int
-- > , first :: First Int
-- > , last :: Last Int
-- > , sum :: Sum Int
-- > , product :: Product Int
-- > } deriving (Generic, Show)
--
-- This gives the following behavior:
--
-- > $ stack runghc Example.hs --
-- > --switch
-- > --optional 1
-- > --list 1 --list 2
-- > --first 1 --first 2
-- > --last 1 --last 2
-- > --sum 1 --sum 2
-- > --product 1 --product 2
-- > Example {switch = True, list = [1,2], optional = Just 1, first = First
-- > {getFirst = Just 1}, last = Last {getLast = Just 2}, sum = Sum {getSum =
-- > 3}, product = Product {getProduct = 2}}
-- >
-- > $ stack runghc Example.hs
-- > Example {switch = False, list = [], optional = Nothing, first = First
-- > {getFirst = Nothing}, second = Last {getLast = Nothing}, sum = Sum {getSum
-- > = 0}, product = Product {getProduct = 1}}
--
-- If a datatype has multiple constructors:
--
-- > data Example
-- > = Create { name :: Text, duration :: Maybe Int }
-- > | Kill { name :: Text }
-- > deriving (Generic, Show)
--
-- ... then they will translate into subcommands named after each constructor:
--
-- > $ stack runghc Example.hs -- create --name foo --duration=60
-- > Create {name = "foo", duration = Just 60}
-- > $ stack runghc Example.hs -- kill --name foo
-- > Kill {name = "foo"}
--
-- This library also provides out-of-the-box support for many existing types,
-- like tuples and `Either`.
--
-- > {-# LANGUAGE DeriveGeneric #-}
-- > {-# LANGUAGE OverloadedStrings #-}
-- >
-- > import Options.Generic
-- >
-- > main = do
-- > x <- getRecord "Test program"
-- > print (x :: Either Double Int)
--
-- > $ stack runghc Example.hs -- left 1.0
-- > Left 1.0
-- > $ stack runghc Example.hs -- right 2
-- > Right 2
--
-- > main = do
-- > x <- getRecord "Test program"
-- > print (x :: (Double, Int))
--
-- > $ stack runghc Example.hs -- 1.0 2
-- > (1.0,2)
--
-- ... and you can also just parse a single value:
--
-- > main = do
-- > x <- getRecord "Test program"
-- > print (x :: Int)
--
-- > $ stack runghc Example.hs -- 2
-- > 2
--
-- However, there are some types that this library cannot generate sensible
-- command-line parsers for, such as:
--
-- * recursive types:
--
-- > data Example = Example { foo :: Example }
--
-- * records whose fields are other records
--
-- > data Outer = Outer { foo :: Inner } deriving (Show, Generic)
-- > data Inner = Inner { bar :: Int } deriving (Show, Generic)
--
-- * record fields with nested `Maybe`s or nested lists
--
-- > data Example = Example { foo :: Maybe (Maybe Int) }
-- > data Example = Example { foo :: [[Int]] }
--
-- If you try to auto-generate a parser for these types you will get an error at
-- compile time that will look something like this:
--
-- > No instance for (ParseFields TheTypeOfYourField)
-- > arising from a use of ‘Options.Generic.$gdmparseRecord’
-- > In the expression: Options.Generic.$gdmparseRecord
-- > In an equation for ‘parseRecord’:
-- > parseRecord = Options.Generic.$gdmparseRecord
-- > In the instance declaration for ‘ParseRecord TheTypeOfYourRecord’
--
-- You can customize the library's default behavior using the
-- `parseRecordWithModifiers` utility, like this:
--
-- > {-# LANGUAGE DeriveGeneric #-}
-- > {-# LANGUAGE OverloadedStrings #-}
-- >
-- > import Options.Generic
-- >
-- > data Example = Example { foo :: Int, bar :: Double }
-- > deriving (Generic, Show)
-- >
-- > modifiers :: Modifiers
-- > modifiers = defaultModifiers
-- > { shortNameModifier = firstLetter
-- > }
-- >
-- > instance ParseRecord Example where
-- > parseRecord = parseRecordWithModifiers modifiers
-- >
-- > main = do
-- > x <- getRecord "Test program"
-- > print (x :: Example)
module Options.Generic (
-- * Parsers
getRecord
, getRecordWith
, getWithHelp
, getRecordPure
, getRecordPureWith
, unwrapRecord
, unwrapWithHelp
, unwrapRecordPure
, ParseRecord(..)
, ParseFields(..)
, ParseField(..)
, Only(..)
, getOnly
, Modifiers(..)
, parseRecordWithModifiers
, defaultModifiers
, lispCaseModifiers
, firstLetter
, GenericParseRecord(..)
-- * Help
, type (<?>)(..)
, type (<!>)(..)
, type (:::)
, Wrapped
, Unwrapped
, Unwrappable
-- * Re-exports
, Generic
, Text
, All(..)
, Any(..)
, First(..)
, Last(..)
, Sum(..)
, Product(..)
) where
import Control.Applicative
import Control.Monad.IO.Class (MonadIO(..))
import Data.Char (isUpper, toLower, toUpper)
import Data.Int (Int8, Int16, Int32, Int64)
import Data.Monoid
import Data.List.NonEmpty (NonEmpty((:|)))
import Data.Proxy
import Data.Text (Text)
import Data.Tuple.Only (Only(..))
import Data.Typeable (Typeable)
import Data.Void (Void)
import Data.Word (Word8, Word16, Word32, Word64)
import Data.Foldable (foldMap)
import Filesystem.Path (FilePath)
import GHC.Generics
import Prelude hiding (FilePath)
import Options.Applicative (Parser, ReadM)
import qualified Data.Text
import qualified Data.Text.Encoding
import qualified Data.Text.Lazy
import qualified Data.Text.Lazy.Encoding
import qualified Data.Time.Calendar
import qualified Data.Time.Format
import qualified Data.Typeable
import qualified Data.ByteString
import qualified Data.ByteString.Lazy
import qualified Filesystem.Path.CurrentOS as Filesystem
import qualified Options.Applicative as Options
import qualified Options.Applicative.Types as Options
import qualified Text.Read
#if MIN_VERSION_base(4,7,0)
import GHC.TypeLits
#else
import Data.Singletons.TypeLits
#endif
#if MIN_VERSION_base(4,8,0)
import Numeric.Natural (Natural)
#endif
auto :: Read a => ReadM a
auto = do
s <- Options.readerAsk
case Text.Read.readMaybe s of
Just x -> return x
Nothing -> Options.readerAbort Options.ShowHelpText
{-| A class for all record fields that can be parsed from exactly one option or
argument on the command line
`parseField` has a default implementation for any type that implements
`Read` and `Typeable`. You can derive `Read` for many types and you can
derive `Typeable` for any type if you enable the @DeriveDataTypeable@
language extension
-}
class ParseField a where
parseField
:: Maybe Text
-- ^ Help message
-> Maybe Text
-- ^ Field label
-> Maybe Char
-- ^ Short name
-> Maybe String
-- ^ Default value
-> Parser a
default parseField
:: Read a
=> Maybe Text
-- ^ Help message
-> Maybe Text
-- ^ Field label
-> Maybe Char
-- ^ Short name
-> Maybe String
-- ^ Default value
-> Parser a
parseField h m c d = do
let proxy = Proxy :: Proxy a
case m of
Nothing -> do
let fs = Options.metavar (metavar proxy)
<> foldMap (Options.help . Data.Text.unpack) h
Options.argument readField fs
Just name -> do
let fs = Options.metavar (metavar proxy)
<> Options.long (Data.Text.unpack name)
<> foldMap (Options.help . Data.Text.unpack) h
<> foldMap Options.short c
<> foldMap Options.value (d >>= Text.Read.readMaybe)
Options.option readField fs
{-| The only reason for this method is to provide a special case for
handling `String`s. All other instances should just fall back on the
default implementation for `parseListOfField`
-}
parseListOfField
:: Maybe Text
-- ^ Help message
-> Maybe Text
-- ^ Field label
-> Maybe Char
-- ^ Short name
-> Maybe String
-- ^ Default value
-> Parser [a]
parseListOfField h m c d = many (parseField h m c d)
readField :: ReadM a
default readField :: Read a => ReadM a
readField = auto
metavar :: proxy a -> String
default metavar :: Typeable a => proxy a -> String
metavar _ = map toUpper (show (Data.Typeable.typeOf (undefined :: a)))
instance ParseField Bool
instance ParseField Double
instance ParseField Float
instance ParseField Integer
instance ParseField Ordering
instance ParseField ()
instance ParseField Void
readIntegralBounded :: forall a. (Integral a, Bounded a, Typeable a) => ReadM a
readIntegralBounded =
auto >>= f
where
f i | i < lower = fail msg
| i > upper = fail msg
| otherwise = pure $ fromInteger i
lower = toInteger (minBound :: a)
upper = toInteger (maxBound :: a)
msg = map toUpper (show (Data.Typeable.typeOf (undefined :: a))) <>
" must be within the range [" <>
show lower <> " .. " <> show upper <> "]"
instance ParseField Int where readField = readIntegralBounded
instance ParseField Int8 where readField = readIntegralBounded
instance ParseField Int16 where readField = readIntegralBounded
instance ParseField Int32 where readField = readIntegralBounded
instance ParseField Int64 where readField = readIntegralBounded
instance ParseField Word8 where readField = readIntegralBounded
instance ParseField Word16 where readField = readIntegralBounded
instance ParseField Word32 where readField = readIntegralBounded
instance ParseField Word64 where readField = readIntegralBounded
#if MIN_VERSION_base(4,8,0)
instance ParseField Natural where
readField =
auto >>= f
where
f i | i < 0 = fail msg
| otherwise = pure $ fromInteger i
msg = "NATURAL cannot be negative"
#endif
instance ParseField String where
parseField = parseHelpfulString "STRING"
instance ParseField Char where
metavar _ = "CHAR"
readField = do
s <- Options.readerAsk
case s of
[ch] -> return ch
_ -> Options.readerAbort Options.ShowHelpText
parseListOfField = parseHelpfulString "STRING"
instance ParseField Any where
metavar _ = "ANY"
parseField h m c d = Any <$> parseField h m c d
instance ParseField All where
metavar _ = "ALL"
parseField h m c d = All <$> parseField h m c d
parseHelpfulString
:: String -> Maybe Text -> Maybe Text -> Maybe Char -> Maybe String -> Parser String
parseHelpfulString metavar h m c d =
case m of
Nothing -> do
let fs = Options.metavar metavar
<> foldMap (Options.help . Data.Text.unpack) h
Options.argument Options.str fs
Just name -> do
let fs = Options.metavar metavar
<> Options.long (Data.Text.unpack name)
<> foldMap (Options.help . Data.Text.unpack) h
<> foldMap Options.short c
<> foldMap Options.value d
Options.option Options.str fs
instance ParseField Data.Text.Text where
parseField h m c d = Data.Text.pack <$> parseHelpfulString "TEXT" h m c d
instance ParseField Data.ByteString.ByteString where
parseField h m c d = fmap Data.Text.Encoding.encodeUtf8 (parseField h m c d)
instance ParseField Data.Text.Lazy.Text where
parseField h m c d = Data.Text.Lazy.pack <$> parseHelpfulString "TEXT" h m c d
instance ParseField Data.ByteString.Lazy.ByteString where
parseField h m c d = fmap Data.Text.Lazy.Encoding.encodeUtf8 (parseField h m c d)
instance ParseField FilePath where
parseField h m c d = Filesystem.decodeString <$> parseHelpfulString "FILEPATH" h m c d
readField = Options.str
instance ParseField Data.Time.Calendar.Day where
metavar _ = "YYYY-MM-DD"
readField = Options.eitherReader
$ runReadS . Data.Time.Format.readSTime
False
Data.Time.Format.defaultTimeLocale
"%F"
where
runReadS [(day, "")] = Right day
runReadS _ = Left "expected YYYY-MM-DD"
{-| A class for all types that can be parsed from zero or more arguments/options
on the command line
`parseFields` has a default implementation for any type that implements
`ParseField`
-}
class ParseRecord a => ParseFields a where
parseFields
:: Maybe Text
-- ^ Help message
-> Maybe Text
-- ^ Field label
-> Maybe Char
-- ^ Short name
-> Maybe String
-- ^ Default value
-> Parser a
default parseFields
:: ParseField a => Maybe Text -> Maybe Text -> Maybe Char -> Maybe String -> Parser a
parseFields = parseField
instance ParseFields Char
instance ParseFields Double
instance ParseFields Float
instance ParseFields Int
instance ParseFields Int8
instance ParseFields Int16
instance ParseFields Int32
instance ParseFields Int64
instance ParseFields Integer
instance ParseFields Ordering
instance ParseFields Void
instance ParseFields Word8
instance ParseFields Word16
instance ParseFields Word32
instance ParseFields Word64
instance ParseFields Data.ByteString.ByteString
instance ParseFields Data.ByteString.Lazy.ByteString
instance ParseFields Data.Text.Text
instance ParseFields Data.Text.Lazy.Text
instance ParseFields FilePath
instance ParseFields Data.Time.Calendar.Day
#if MIN_VERSION_base(4,8,0)
instance ParseFields Natural
#endif
instance ParseFields Bool where
parseFields h m c d =
case m of
Nothing -> do
let fs = Options.metavar "BOOL"
<> foldMap (Options.help . Data.Text.unpack) h
Options.argument auto fs
Just name -> case d >>= Text.Read.readMaybe of
Nothing -> Options.switch $
Options.long (Data.Text.unpack name)
<> foldMap (Options.help . Data.Text.unpack) h
<> foldMap Options.short c
Just d0 -> Options.flag d0 (not d0) $
Options.long (Data.Text.unpack name)
<> foldMap (Options.help . Data.Text.unpack) h
<> foldMap Options.short c
instance ParseFields () where
parseFields _ _ _ _ = pure ()
instance ParseFields Any where
parseFields h m c d = (fmap mconcat . many . fmap Any) (parseField h m c d)
instance ParseFields All where
parseFields h m c d = (fmap mconcat . many . fmap All) (parseField h m c d)
instance ParseField a => ParseFields (Maybe a) where
parseFields h m c d = optional (parseField h m c d)
instance ParseField a => ParseFields (First a) where
parseFields h m c d = (fmap mconcat . many . fmap (First . Just)) (parseField h m c d)
instance ParseField a => ParseFields (Last a) where
parseFields h m c d = (fmap mconcat . many . fmap (Last . Just)) (parseField h m c d)
instance (Num a, ParseField a) => ParseFields (Sum a) where
parseFields h m c d = (fmap mconcat . many . fmap Sum) (parseField h m c d)
instance (Num a, ParseField a) => ParseFields (Product a) where
parseFields h m c d = (fmap mconcat . many . fmap Product) (parseField h m c d)
instance ParseField a => ParseFields [a] where
parseFields = parseListOfField
instance ParseField a => ParseFields (NonEmpty a) where
parseFields h m c d = (:|) <$> parseField h m c d <*> parseListOfField h m c d
{-| Use this to annotate a field with a type-level string (i.e. a `Symbol`)
representing the help description for that field:
> data Example = Example
> { foo :: Int <?> "Documentation for the foo flag"
> , bar :: Double <?> "Documentation for the bar flag"
> } deriving (Generic, Show)
-}
newtype (<?>) (field :: *) (help :: Symbol) = Helpful { unHelpful :: field } deriving (Generic, Show)
instance (ParseField a, KnownSymbol h) => ParseField (a <?> h) where
parseField _ m c d = Helpful <$>
parseField ((Just . Data.Text.pack .symbolVal) (Proxy :: Proxy h)) m c d
readField = Helpful <$> readField
metavar _ = metavar (Proxy :: Proxy a)
instance (ParseFields a, KnownSymbol h) => ParseFields (a <?> h) where
parseFields _ m c d = Helpful <$>
parseFields ((Just . Data.Text.pack .symbolVal) (Proxy :: Proxy h)) m c d
instance (ParseFields a, KnownSymbol h) => ParseRecord (a <?> h)
{-| Use this to annotate a field with a type-level string (i.e. a `Symbol`)
representing the default value for that field:
> data Example = Example
> { foo :: Int <!> "1"
> , bar :: Double <!> "0.5"
> } deriving (Generic, Show)
-}
newtype (<!>) (field :: *) (value :: Symbol) = DefValue { unDefValue :: field } deriving (Generic, Show)
instance (ParseField a, KnownSymbol d) => ParseField (a <!> d) where
parseField h m c _ = DefValue <$> parseField h m c (Just (symbolVal (Proxy :: Proxy d)))
readField = DefValue <$> readField
metavar _ = metavar (Proxy :: Proxy a)
instance (ParseFields a, KnownSymbol d) => ParseFields (a <!> d) where
parseFields h m c _ = DefValue <$> parseFields h m c (Just (symbolVal (Proxy :: Proxy d)))
instance (ParseFields a, KnownSymbol h) => ParseRecord (a <!> h)
{-| A 1-tuple, used solely to translate `ParseFields` instances into
`ParseRecord` instances
-}
newtype Only_ a = Only_ a deriving (Generic, Show)
{-| This is a convenience function that you can use if you want to create a
`ParseRecord` instance that just defers to the `ParseFields` instance for
the same type:
> instance ParseRecord MyType where
> parseRecord = fmap getOnly parseRecord
-}
getOnly :: Only a -> a
getOnly (Only x) = x
{-| A class for types that can be parsed from the command line
This class has a default implementation for any type that implements
`Generic` and you can derive `Generic` for many types by enabling the
@DeriveGeneric@ language extension
You can also use `getOnly` to create a `ParseRecord` instance from a
`ParseFields` instance:
> instance ParseRecord MyType where
> parseRecord = fmap getOnly parseRecord
-}
class ParseRecord a where
parseRecord :: Parser a
default parseRecord :: (Generic a, GenericParseRecord (Rep a)) => Parser a
parseRecord = fmap GHC.Generics.to (genericParseRecord defaultModifiers)
instance ParseFields a => ParseRecord (Only_ a)
instance ParseFields a => ParseRecord (Only a) where
parseRecord = fmap adapt parseRecord
where
adapt (Only_ x) = Only x
instance ParseRecord Char where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Double where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Float where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Int where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Int8 where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Int16 where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Int32 where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Int64 where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Ordering
instance ParseRecord Void
instance ParseRecord Word8 where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Word16 where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Word32 where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Word64 where
parseRecord = fmap getOnly parseRecord
instance ParseRecord ()
#if MIN_VERSION_base(4,8,0)
instance ParseRecord Natural where
parseRecord = fmap getOnly parseRecord
#endif
instance ParseRecord Bool where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Integer where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Data.Text.Text where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Data.Text.Lazy.Text where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Any where
parseRecord = fmap getOnly parseRecord
instance ParseRecord All where
parseRecord = fmap getOnly parseRecord
instance ParseRecord FilePath where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Data.ByteString.ByteString where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Data.ByteString.Lazy.ByteString where
parseRecord = fmap getOnly parseRecord
instance ParseRecord Data.Time.Calendar.Day where
parseRecord = fmap getOnly parseRecord
instance ParseField a => ParseRecord (Maybe a) where
parseRecord = fmap getOnly parseRecord
instance ParseField a => ParseRecord (First a) where
parseRecord = fmap getOnly parseRecord
instance ParseField a => ParseRecord (Last a) where
parseRecord = fmap getOnly parseRecord
instance (Num a, ParseField a) => ParseRecord (Sum a) where
parseRecord = fmap getOnly parseRecord
instance (Num a, ParseField a) => ParseRecord (Product a) where
parseRecord = fmap getOnly parseRecord
instance ParseField a => ParseRecord [a] where
parseRecord = fmap getOnly parseRecord
instance ParseField a => ParseRecord (NonEmpty a) where
parseRecord = fmap getOnly parseRecord
instance (ParseFields a, ParseFields b) => ParseRecord (a, b)
instance (ParseFields a, ParseFields b, ParseFields c) => ParseRecord (a, b, c)
instance (ParseFields a, ParseFields b, ParseFields c, ParseFields d) => ParseRecord (a, b, c, d)
instance (ParseFields a, ParseFields b, ParseFields c, ParseFields d, ParseFields e) => ParseRecord (a, b, c, d, e)
instance (ParseFields a, ParseFields b, ParseFields c, ParseFields d, ParseFields e, ParseFields f) => ParseRecord (a, b, c, d, e, f)
instance (ParseFields a, ParseFields b, ParseFields c, ParseFields d, ParseFields e, ParseFields f, ParseFields g) => ParseRecord (a, b, c, d, e, f, g)
instance (ParseFields a, ParseFields b) => ParseRecord (Either a b)
{-| Options for customizing derived `ParseRecord` implementations for `Generic`
types
You can either create the `Modifiers` record directly:
> modifiers :: Modifiers
> modifiers = Modifiers
> { fieldNameModifier = ...
> , constructorNameModifier = ...
> , shortNameModifier = ...
> }
... or you can tweak the `defaultModifiers`:
> modifiers :: Modifiers
> modifiers = defaultModifiers { fieldNameModifier = ... }
... or you can use/tweak a predefined `Modifier`, like `lispCaseModifiers`
The `parseRecordWithModifiers` function uses this `Modifiers` record when
generating a `Generic` implementation of `ParseRecord`
-}
data Modifiers = Modifiers
{ fieldNameModifier :: String -> String
-- ^ Transform the name of derived fields (Default: @id@)
, constructorNameModifier :: String -> String
-- ^ Transform the name of derived constructors (Default: @map toLower@)
, shortNameModifier :: String -> Maybe Char
-- ^ Derives an optional short name from the field name (Default: @\\_ -> Nothing@)
}
{-| These are the default modifiers used if you derive a `Generic`
implementation. You can customize this and pass the result to
`parseRecordWithModifiers` if you would like to modify the derived
implementation:
> myModifiers :: Modifiers
> myModifiers = defaultModifiers { constructorNameModifier = id }
>
> instance ParseRecord MyType where
> parseRecord = parseRecordWithModifiers myModifiers
-}
defaultModifiers :: Modifiers
defaultModifiers = Modifiers
{ fieldNameModifier = id
, constructorNameModifier = map toLower
, shortNameModifier = \_ -> Nothing
}
-- | Convert field and constructor names from @CamelCase@ to @lisp-case@.
--
-- Leading underscores are dropped, allowing one to use option names
-- which are Haskell keywords or otherwise conflicting identifiers.
--
-- > BuildCommand -> build-command
-- > someFlag -> --some-flag
-- > _type -> --type
-- > _splitAt -> --split-at
lispCaseModifiers :: Modifiers
lispCaseModifiers = Modifiers lispCase lispCase (\_ -> Nothing)
where
lispCase = dropWhile (== '-') . (>>= lower) . dropWhile (== '_')
lower c | isUpper c = ['-', toLower c]
| otherwise = [c]
{-| Use this for the `shortNameModifier` field of the `Modifiers` record if
you want to use the first letter of each option as the short name
-}
firstLetter :: String -> Maybe Char
firstLetter (c:_) = Just c
firstLetter _ = Nothing
class GenericParseRecord f where
genericParseRecord :: Modifiers -> Parser (f p)
instance GenericParseRecord U1 where
genericParseRecord _ = pure U1
-- See: [NOTE - Sums]
instance GenericParseRecord f => GenericParseRecord (M1 C c f) where
genericParseRecord = fmap M1 . genericParseRecord
-- See: [NOTE - Sums]
instance (GenericParseRecord (f :+: g), GenericParseRecord (h :+: i)) => GenericParseRecord ((f :+: g) :+: (h :+: i)) where
genericParseRecord mods = do
fmap L1 (genericParseRecord mods) <|> fmap R1 (genericParseRecord mods)
-- See: [NOTE - Sums]
instance (Constructor c, GenericParseRecord f, GenericParseRecord (g :+: h)) => GenericParseRecord (M1 C c f :+: (g :+: h)) where
genericParseRecord mods@Modifiers{..} = do
let m :: M1 i c f a
m = undefined
let name = constructorNameModifier (conName m)
let info = Options.info (Options.helper <*> (genericParseRecord mods)) mempty
let subparserFields =
Options.command name info
<> Options.metavar name
let parser = Options.subparser subparserFields
fmap (L1 . M1) parser <|> fmap R1 (genericParseRecord mods)
-- See: [NOTE - Sums]
instance (Constructor c, GenericParseRecord (f :+: g), GenericParseRecord h) => GenericParseRecord ((f :+: g) :+: M1 C c h) where
genericParseRecord mods@Modifiers{..} = do
let m :: M1 i c h a
m = undefined
let name = constructorNameModifier (conName m)
let info = Options.info (Options.helper <*> (genericParseRecord mods)) mempty
let subparserFields =
Options.command name info
<> Options.metavar name
let parser = Options.subparser subparserFields
fmap L1 (genericParseRecord mods) <|> fmap (R1 . M1) parser
-- See: [NOTE - Sums]
instance (Constructor c1, Constructor c2, GenericParseRecord f1, GenericParseRecord f2) => GenericParseRecord (M1 C c1 f1 :+: M1 C c2 f2) where
genericParseRecord mods@Modifiers{..} = do
let m1 :: M1 i c1 f a
m1 = undefined
let m2 :: M1 i c2 g a
m2 = undefined
let name1 = constructorNameModifier (conName m1)
let name2 = constructorNameModifier (conName m2)
let info1 = Options.info (Options.helper <*> (genericParseRecord mods)) mempty
let info2 = Options.info (Options.helper <*> (genericParseRecord mods)) mempty
let subparserFields1 =
Options.command name1 info1
<> Options.metavar name1
let subparserFields2 =
Options.command name2 info2
<> Options.metavar name2
let parser1 = Options.subparser subparserFields1
let parser2 = Options.subparser subparserFields2
fmap (L1 . M1) parser1 <|> fmap (R1 . M1) parser2
instance (GenericParseRecord f, GenericParseRecord g) => GenericParseRecord (f :*: g) where
genericParseRecord mods = liftA2 (:*:) (genericParseRecord mods) (genericParseRecord mods)
instance GenericParseRecord V1 where
genericParseRecord _ = empty
instance (Selector s, ParseFields a) => GenericParseRecord (M1 S s (K1 i a)) where
genericParseRecord Modifiers{..} = do
let m :: M1 i s f a
m = undefined
let label = case selName m of
"" -> Nothing
name -> Just (Data.Text.pack (fieldNameModifier name))
let shortName = shortNameModifier (selName m)
fmap (M1 . K1) (parseFields Nothing label shortName Nothing)
{- [NOTE - Sums]
You might wonder why the `GenericParseRecord` instances for `(:+:)` are so
complicated. A much simpler approach would be something like this:
> instance (GenericParseRecord f, GenericParseRecord g) => GenericParseRecord (f :+: g) where
> genericParseRecord = fmap L1 genericParseRecord <|> fmap R1 genericParseRecord
>
> instance (Constructor c, GenericParseRecord f) => GenericParseRecord (M1 C c f) where
> genericParseRecord = do
> let m :: M1 i c f a
> m = undefined
>
> let name = map toLower (conName m)
>
> let info = Options.info genericParseRecord mempty
>
> let subparserFields =
> Options.command n info
> <> Options.metavar n
>
> fmap M1 (Options.subparser subparserFields)
The reason for the extra complication is so that datatypes with just one
constructor don't have subcommands. That way, if a user defines a data
type like:
> data Example = Example { foo :: Double } deriving (Generic)
>
> instance ParseRecord Example
.. then the command line will only read in the @--foo@ flag and won't
expect a gratuitous @example@ subcommand:
> ./example --foo 2
However, if a user defines a data type with two constructors then the
subcommand support will kick in.
Some other alternatives that I considered and rejected:
* Alternative #1: Constructors prefixed with something like @Command_@ are
turned into sub-commands named after the constructor with the prefix
stripped. If the prefix is not present then they don't get a subcommand.
I rejected this approach for several reasons:
* It's ugly
* It's error-prone (consider the case: @data T = C1 Int | C2 Int@, which
would never successfully parse @C2@). Subcommands should be mandatory
for types with multiple constructors
* It doesn't work "out-of-the-box" for most types in the Haskell
ecosystem which were not written with this library in mind
* Alternative #2: Any constructor named some reserved name (like @Only@)
would not generate a sub-command.
I rejected this approach for a couple of reasons:
* Too surprising. The user would never know or guess about this
behavior without reading the documentation.
* Doesn't work "out-of-the-box" for single-constructor types in the
Haskell ecosystem (like `(a, b)`, for example)
-}
instance GenericParseRecord f => GenericParseRecord (M1 D c f) where
genericParseRecord mods = fmap M1 (Options.helper <*> genericParseRecord mods)
{-| Use `parseRecordWithModifiers` when you want to tweak the behavior of a
derived `ParseRecord` implementation, like this:
> myModifiers :: Modifiers
> myModifiers = defaultModifiers { constructorNameModifier = id }
>
> instance ParseRecord MyType where
> parseRecord = parseRecordWithModifiers myModifiers
This will still require that you derive `Generic` for your type to automate
most of the implementation, but the `Modifiers` that you pass will change
how the implementation generates the command line interface
-}
parseRecordWithModifiers
:: (Generic a, GenericParseRecord (Rep a)) => Modifiers -> Parser a
parseRecordWithModifiers mods = fmap GHC.Generics.to (genericParseRecord mods)
-- | Marshal any value that implements `ParseRecord` from the command line
--
-- If you need to modify the top-level 'ParserInfo' or 'ParserPrefs'
-- use the 'getRecordWith' function.
getRecord
:: (MonadIO io, ParseRecord a)
=> Text
-- ^ Program description
-> io a
getRecord desc = getRecordWith header mempty
where
header = Options.header (Data.Text.unpack desc)
-- | Marshal any value that implements `ParseRecord` from the command line
--
-- This is the lower-level sibling of 'getRecord and lets you modify
-- the 'ParserInfo' and 'ParserPrefs' records.
getRecordWith
:: (MonadIO io, ParseRecord a)
=> Options.InfoMod a
-- ^ 'ParserInfo' modifiers
-> Options.PrefsMod
-- ^ 'ParserPrefs' modifiers
-> io a
getRecordWith infoMods prefsMods = liftIO (Options.customExecParser prefs info)
where
prefs = Options.prefs (defaultParserPrefs <> prefsMods)
info = Options.info parseRecord infoMods
-- | Marshal any value that implements `ParseRecord` from the commmand line
-- alongside an io action that prints the help message.
getWithHelp
:: (MonadIO io, ParseRecord a)
=> Text
-- ^ Program description
-> io (a, io ())
-- ^ (options, io action to print help message)
getWithHelp desc = do
a <- getRecordWith header mempty
return (a, help)
where
header = Options.header (Data.Text.unpack desc)
info = Options.info parseRecord header
help = liftIO (showHelpText (Options.prefs defaultParserPrefs) info)
{-| Pure version of `getRecord`
If you need to modify the parser's 'ParserInfo' or 'ParserPrefs', use
`getRecordPureWith`.
>>> :set -XOverloadedStrings
>>> getRecordPure ["1"] :: Maybe Int
Just 1
>>> getRecordPure ["1", "2"] :: Maybe [Int]
Just [1,2]
>>> getRecordPure ["Foo"] :: Maybe Int
Nothing
-}
getRecordPure
:: ParseRecord a
=> [Text]
-- ^ Command-line arguments
-> Maybe a
getRecordPure args = getRecordPureWith args mempty mempty
{-| Pure version of `getRecordWith`
Like `getRecordWith`, this is a sibling of 'getRecordPure and
exposes the monoidal modifier structures for 'ParserInfo' and
'ParserPrefs' to you.
>>> :set -XOverloadedStrings
>>> getRecordPureWith ["1"] mempty mempty :: Maybe Int
Just 1
>>> getRecordPureWith ["1", "2"] mempty mempty :: Maybe [Int]
Just [1,2]
>>> getRecordPureWith ["Foo"] mempty mempty :: Maybe Int
Nothing
-}
getRecordPureWith
:: ParseRecord a
=> [Text]
-- ^ Command-line arguments
-> Options.InfoMod a
-- ^ 'ParserInfo' modifiers
-> Options.PrefsMod
-- ^ 'ParserPrefs' modifiers
-> Maybe a
getRecordPureWith args infoMod prefsMod = do
let header = Options.header ""
let info = Options.info parseRecord (header <> infoMod)
let prefs = Options.prefs (defaultParserPrefs <> prefsMod)
let args' = map Data.Text.unpack args
Options.getParseResult (Options.execParserPure prefs info args')
-- | @optparse-generic@'s flavor of options.
defaultParserPrefs :: Options.PrefsMod
defaultParserPrefs = Options.multiSuffix "..."
-- | A type family to extract fields wrapped using '(<?>)'
type family (:::) wrap wrapped
type instance Wrapped ::: wrapped = wrapped
type instance Unwrapped ::: wrapped = Unwrap wrapped
type family Unwrap ty where
Unwrap (ty <?> helper) = Unwrap ty
Unwrap (ty <!> defVal) = Unwrap ty
Unwrap ty = ty
infixr 0 :::
-- | Flag to keep fields wrapped
data Wrapped
-- | Flag to unwrap fields annotated using '(<?>)'
data Unwrapped
-- | Constraint for types whose fields can be unwrapped
type Unwrappable f = (Generic (f Wrapped), Generic (f Unwrapped), GenericUnwrappable (Rep (f Wrapped)) (Rep (f Unwrapped)))
class GenericUnwrappable f f' where
genericUnwrap :: f p -> f' p
instance GenericUnwrappable U1 U1 where
genericUnwrap = id
instance GenericUnwrappable f f' => GenericUnwrappable (M1 i c f) (M1 i c f') where
genericUnwrap = M1 . genericUnwrap . unM1
instance (GenericUnwrappable f f', GenericUnwrappable g g') => GenericUnwrappable (f :+: g) (f' :+: g') where
genericUnwrap (L1 f) = L1 (genericUnwrap f)
genericUnwrap (R1 g) = R1 (genericUnwrap g)
instance (GenericUnwrappable f f', GenericUnwrappable g g') => GenericUnwrappable (f :*: g) (f' :*: g') where
genericUnwrap (f :*: g) = genericUnwrap f :*: genericUnwrap g
instance GenericUnwrappable (K1 i c) (K1 i c) where
genericUnwrap = id
instance GenericUnwrappable (K1 i field) (K1 i c)
=> GenericUnwrappable (K1 i (field <?> helper)) (K1 i c) where
genericUnwrap (K1 c) = (genericUnwrap :: K1 i field p -> K1 i c p) (K1 (unHelpful c))
instance GenericUnwrappable (K1 i field) (K1 i c)
=> GenericUnwrappable (K1 i (field <!> defVal)) (K1 i c) where
genericUnwrap (K1 c) = (genericUnwrap :: K1 i field p -> K1 i c p) (K1 (unDefValue c))
-- | Unwrap the fields of a constructor
unwrap :: forall f . Unwrappable f => f Wrapped -> f Unwrapped
unwrap = to . genericUnwrap . from
-- | Marshal any value that implements 'ParseRecord' from the command line
-- and unwrap its fields
unwrapRecord
:: (Functor io, MonadIO io, ParseRecord (f Wrapped), Unwrappable f)
=> Text
-> io (f Unwrapped)
unwrapRecord = fmap unwrap . getRecord
-- | Pure version of `unwrapRecord`
unwrapRecordPure
:: (ParseRecord (f Wrapped), Unwrappable f)
=> [Text]
-- ^ Command-line arguments
-> Maybe (f Unwrapped)
unwrapRecordPure = fmap unwrap . getRecordPure
showHelpText :: Options.ParserPrefs -> Options.ParserInfo a -> IO ()
showHelpText pprefs pinfo =
Options.handleParseResult . Options.Failure $
Options.parserFailure pprefs pinfo Options.ShowHelpText mempty
-- | Marshal any value that implements 'ParseRecord' from the command line
-- and unwrap its fields alongside an io action to print the help message
unwrapWithHelp
:: (MonadIO io, ParseRecord (f Wrapped), Unwrappable f)
=> Text
-- ^ Program description
-> io (f Unwrapped, io ())
-- ^ (options, io action to print help message)
unwrapWithHelp desc = do
(opts, help) <- getWithHelp desc
return (unwrap opts, help)