Language.Nix.Path

Documentation

data Path

Paths are non-empty lists of identifiers in Nix.

>>> path # [ident # "yo"]
Path [Identifier "yo"]

Any attempt to construct the empty path throws an error:

>>> :set -XScopedTypeVariables
>>> either (\(_::SomeException) -> "empty paths are illegal") show <$> Excpt.try (evaluate (path # []))
"empty paths are illegal"

Paths can be pretty-printed and parsed with the Text class:

>>> parse "Path" "foo.\"foo.bar\".bar" :: Path
Path [Identifier "foo",Identifier "foo.bar",Identifier "bar"]
>>> pPrint (parse "Path" "foo.\"foo\".\"bar\".bar" :: Path)
foo.foo.bar.bar

\p -> Just (p :: Path) == parseM "Path" (prettyShow p)

Paths are instances of strings and can be implicitly converted:

>>> :set -XOverloadedStrings
>>> pPrint $ ("yo.bar" :: Path)
yo.bar
>>> pPrint $ ("  yo  .  bar" :: Path)
yo.bar

Freaky quoted identifiers are fine throughout:

>>> pPrint $ path # ["yo","b\"ar"]
yo."b\"ar"
>>> pPrint ("\"5ident\"" :: Path)
"5ident"
>>> pPrint $ path # ["5ident","foo.bar","foo\nbar"]
"5ident"."foo.bar"."foo\nbar"

Instances

Eq Path

Defined in Language.Nix.Path

Methods

(==) :: Path -> Path -> Bool

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

Ord Path

Defined in Language.Nix.Path

Methods

compare :: Path -> Path -> Ordering

(<) :: Path -> Path -> Bool

(<=) :: Path -> Path -> Bool

(>) :: Path -> Path -> Bool

(>=) :: Path -> Path -> Bool

max :: Path -> Path -> Path

min :: Path -> Path -> Path

Show Path

Defined in Language.Nix.Path

Methods

showsPrec :: Int -> Path -> ShowS

show :: Path -> String

showList :: [Path] -> ShowS

IsString Path

Defined in Language.Nix.Path

Methods

fromString :: String -> Path

Generic Path

Defined in Language.Nix.Path

Associated Types

type Rep Path :: Type -> Type

Methods

from :: Path -> Rep Path x

to :: Rep Path x -> Path

Arbitrary Path

Defined in Language.Nix.Path

Methods

arbitrary :: Gen Path

shrink :: Path -> [Path]

CoArbitrary Path

Defined in Language.Nix.Path

Methods

coarbitrary :: Path -> Gen b -> Gen b

NFData Path

Defined in Language.Nix.Path

Methods

rnf :: Path -> ()

HasParser Path

Defined in Language.Nix.Path

Methods

parser :: CharParser st input m Path

Pretty Path

Defined in Language.Nix.Path

Methods

pPrintPrec :: PrettyLevel -> Rational -> Path -> Doc

pPrint :: Path -> Doc

pPrintList :: PrettyLevel -> [Path] -> Doc

type Rep Path

Defined in Language.Nix.Path

type Rep Path = D1 (MetaData "Path" "Language.Nix.Path" "language-nix-2.2.0-4V8HiyuJODaH1hiGHTNPvO" True) (C1 (MetaCons "Path" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 [Identifier])))

path :: Iso' Path [Identifier]

Use this isomorphism to construct a path from a list of identifiers, or to access that list for a given path.