Pathy.Path

data Path (a :: RelOrAbs) (b :: DirOrFile)

A type that describes a Path. All flavors of paths are described by this type, whether they are absolute or relative paths and whether they refer to files or directories.

• The type parameter a describes whether the path is Rel or Abs.
• The type parameter b describes whether the path is File or Dir.

To ensure type safety, there is no way for users to create a value of this type directly. Instead, helpers should be used, such as rootDir, currentDir, file, dir, (</>), and parsePath.

This ADT allows invalid paths (e.g. paths inside files), but there is no possible way for such paths to be constructed by user-land code.

Instances

• Eq (Path a b)
• Ord (Path a b)
• (IsRelOrAbs a, IsDirOrFile b) => Show (Path a b)

type AnyPath a = Either (Path a Dir) (Path a File)

A type describing a file or directory path.

type RelPath = AnyPath Rel

A type describing a relative file or directory path.

type AbsPath = AnyPath Abs

A type describing an absolute file or directory path.

type RelDir = Path Rel Dir

A type describing a directory whose location is given relative to some other, unspecified directory (referred to as the "current directory").

type AbsDir = Path Abs Dir

A type describing a directory whose location is absolutely specified.

type AnyDir = Either AbsDir RelDir

A type describing a absolute or relative directory path.

type RelFile = Path Rel File

A type describing a file whose location is given relative to some other, unspecified directory (referred to as the "current directory").

type AbsFile = Path Abs File

A type describing a file whose location is absolutely specified.

type AnyFile = Either AbsFile RelFile

A type describing a absolute or relative file path.

rootDir :: Path Abs Dir

The root directory, which can be used to define absolutely-located resources.

currentDir :: Path Rel Dir

The "current directory", which can be used to define relatively-located resources.

dir :: forall s. IsName s => SProxy s -> Path Rel Dir

Creates a path which points to a relative directory of the specified name.

Instead of accepting a runtime value, this function accepts a type-level string via a proxy, to ensure the constructed name is not empty.

dir' :: Name Dir -> Path Rel Dir

Creates a path which points to a relative directory of the specified name.

file :: forall s. IsName s => SProxy s -> Path Rel File

Creates a path which points to a relative file of the specified name.

Instead of accepting a runtime value, this function accepts a type-level string via a proxy, to ensure the constructed name is not empty.

file' :: Name File -> Path Rel File

Creates a path which points to a relative file of the specified name.

in' :: forall a. Name a -> Path Rel a

Creates a path which points to a relative directory or file of the specified name. In most cases dir' or file' should be used instead, but it's still there in case the segment type is going to be determined based on some type variable.

p == maybe p (\(Tuple r n) -> r </> in' n) (peel p)

parentOf :: forall a. IsRelOrAbs a => Path a Dir -> Path a Dir

Creates a path that points to the parent directory of the specified path.

Calling parentOf on rootDir will return rootDir.

extendPath :: forall b a. Path a Dir -> Name b -> Path a b

Extends a path with a file or directory under the current path.

appendPath :: forall b a. IsRelOrAbs a => Path a Dir -> Path Rel b -> Path a b

Given a directory path, appends a relative path to extend the original path.

Operator alias for Pathy.Path.appendPath (left-associative / precedence 6)

parentAppend :: forall b a. IsRelOrAbs a => Path a Dir -> Path Rel b -> Path a b

Ascends into the parent of the specified directory, then descends into the specified path.

rootDir </> dir "foo" <..> dir "bar" = rootDir </> dir "bar"

Operator alias for Pathy.Path.parentAppend (left-associative / precedence 6)

foldPath :: forall r b a. r -> (Path Rel Dir -> r) -> (Path a Dir -> Name b -> r) -> Path a b -> r

A fold over Paths. Since Path has private constructors, this allows for functions to be written over its constructors, similar to a total pattern match.

• The first argument is the value to return for the currentDir/rootDir at the base of the path.
• The second argument is a function for handling a step into the parent directory of the path it receives (eliminates parentOf).
• The third argument is a function representing a file or directory within the directory of the path it receives (eliminates extendPath).

peel :: forall b a. Path a b -> Maybe (Tuple (Path a Dir) (Name b))

Peels off the last directory and the terminal file or directory name from the path. Returns Nothing if the path is rootDir / currentDir or a relative path that is ascending (../)

peelFile :: forall a. Path a File -> Tuple (Path a Dir) (Name File)

Peels off the last director and terminal file from a path. Unlike the general peel function this is guaranteed to return a result, as File paths are known to have a name.

name :: forall b a. IsRelOrAbs a => IsDirOrFile b => Path a b -> Maybe (Name b)

Retrieves the name of the terminal segment in a path. Returns Nothing if the path is rootDir / currentDir or some parentOf p.

fileName :: forall a. Path a File -> Name File

Retrieves the name of a file path. Unlike the general name function, this is guaranteed to return a result, as File paths are known to have a name.

rename :: forall b a. (Name b -> Name b) -> Path a b -> Path a b

Attempts to rename the terminal segment of a path. If the path is rootDir / currentDir or a relative path that is ascending (../) this will have no effect.

renameTraverse :: forall b a f. Applicative f => (Name b -> f (Name b)) -> Path a b -> f (Path a b)

Attempts to rename the terminal segment of a path using a function that returns the result in some Applicative. If the path is rootDir / currentDir or a relative path that is ascending (../) this will have no effect.

setExtension :: forall b a. Path a b -> String -> Path a b

Sets the extension on the terminal segment of a path. If the path is rootDir / currentDir or a relative path that is ascending (../) this will have no effect.

file "image" <.> "png"

See splitName and alterExtension fore more examples.

Operator alias for Pathy.Path.setExtension (left-associative / precedence 6)

relativeTo :: forall b. Path Abs b -> Path Abs Dir -> Path Rel b

Makes a path relative to a reference path. This function is best explaned using this property:

a == r </> a `relativeTo` r

refine :: forall b a. IsDirOrFile b => (Name File -> Name File) -> (Name Dir -> Name Dir) -> Path a b -> Path a b

Refines path segments but does not change anything else.