lens-5.2.3: Lenses, Folds and Traversals

Copyright | (C) 2012-16 Edward Kmett
License | BSD-style (see the file LICENSE)
Maintainer | Edward Kmett <ekmett@gmail.com>
Stability | experimental
Portability | Rank2Types
Safe Haskell | Safe-Inferred
Language | Haskell2010

System.FilePath.Lens

Contents

- Operators
- Lenses

Description

Synopsis

- (</>~) :: ASetter s t FilePath FilePath -> FilePath -> s -> t
- (<</>~) :: LensLike ((,) FilePath) s a FilePath FilePath -> FilePath -> s -> (FilePath, a)
- (<<</>~) :: Optical' (->) q ((,) FilePath) s FilePath -> FilePath -> q s (FilePath, s)
- (<.>~) :: ASetter s a FilePath FilePath -> String -> s -> a
- (<<.>~) :: LensLike ((,) FilePath) s a FilePath FilePath -> String -> s -> (FilePath, a)
- (<<<.>~) :: Optical' (->) q ((,) FilePath) s FilePath -> String -> q s (FilePath, s)
- (</>=) :: MonadState s m => ASetter' s FilePath -> FilePath -> m ()
- (<</>=) :: MonadState s m => LensLike' ((,) FilePath) s FilePath -> FilePath -> m FilePath
- (<<</>=) :: MonadState s m => LensLike' ((,) FilePath) s FilePath -> FilePath -> m FilePath
- (<.>=) :: MonadState s m => ASetter' s FilePath -> String -> m ()
- (<<.>=) :: MonadState s m => LensLike' ((,) FilePath) s FilePath -> String -> m FilePath
- (<<<.>=) :: MonadState s m => LensLike' ((,) FilePath) s FilePath -> String -> m FilePath
- basename :: Lens' FilePath FilePath
- directory :: Lens' FilePath FilePath
- extension :: Lens' FilePath FilePath
- filename :: Lens' FilePath FilePath

# Operators

(</>~) :: ASetter s t FilePath FilePath -> FilePath -> s -> t infixr 4 #

Modify the path by adding another path.

    >>> (both </>~ "bin" $ ("hello","world")) == ("hello" </> "bin", "world" </> "bin")
    True

    (</>~) :: Setter s a FilePath FilePath -> FilePath -> s -> a
    (</>~) :: Iso s a FilePath FilePath -> FilePath -> s -> a
    (</>~) :: Lens s a FilePath FilePath -> FilePath -> s -> a
    (</>~) :: Traversal s a FilePath FilePath -> FilePath -> s -> a

(<</>~) :: LensLike ((,) FilePath) s a FilePath FilePath -> FilePath -> s -> (FilePath, a) infixr 4 #

Add a path onto the end of the target of a `Lens` and return the result

When you do not need the result of the operation, (`</>~`) is more flexible.

(<<</>~) :: Optical' (->) q ((,) FilePath) s FilePath -> FilePath -> q s (FilePath, s) infixr 4 #

Add a path onto the end of the target of a `Lens` and return the original value.

When you do not need the original value, (`</>~`) is more flexible.

(<.>~) :: ASetter s a FilePath FilePath -> String -> s -> a infixr 4 #

Modify the path by adding an extension.

    >>> both <.>~ "txt" $ ("hello","world")
    ("hello.txt","world.txt")

    (<.>~) :: Setter s a FilePath FilePath -> String -> s -> a
    (<.>~) :: Iso s a FilePath FilePath -> String -> s -> a
    (<.>~) :: Lens s a FilePath FilePath -> String -> s -> a
    (<.>~) :: Traversal s a FilePath FilePath -> String -> s -> a

(<<.>~) :: LensLike ((,) FilePath) s a FilePath FilePath -> String -> s -> (FilePath, a) infixr 4 #

Add an extension onto the end of the target of a `Lens` and return the result

    >>> _1 <<.>~ "txt" $ ("hello","world")
    ("hello.txt",("hello.txt","world"))

When you do not need the result of the operation, (`<.>~`) is more flexible.

(<<<.>~) :: Optical' (->) q ((,) FilePath) s FilePath -> String -> q s (FilePath, s) infixr 4 #

Add an extension onto the end of the target of a `Lens` but return the old value

    >>> _1 <<<.>~ "txt" $ ("hello","world")
    ("hello",("hello.txt","world"))

When you do not need the old value, (`<.>~`) is more flexible.

(</>=) :: MonadState s m => ASetter' s FilePath -> FilePath -> m () infix 4 #

Modify the target(s) of a `Lens'`, `Iso'`, `Setter'` or `Traversal'` by adding a path.

    >>> execState (both </>= "bin") ("hello","world") == ("hello" </> "bin", "world" </> "bin")
    True

    (</>=) :: MonadState s m => Setter' s FilePath -> FilePath -> m ()
    (</>=) :: MonadState s m => Iso' s FilePath -> FilePath -> m ()
    (</>=) :: MonadState s m => Lens' s FilePath -> FilePath -> m ()
    (</>=) :: MonadState s m => Traversal' s FilePath -> FilePath -> m ()

(<</>=) :: MonadState s m => LensLike' ((,) FilePath) s FilePath -> FilePath -> m FilePath infix 4 #

Add a path onto the end of the target of a `Lens` into your monad's state and return the result.

When you do not need the result of the operation, (`</>=`) is more flexible.

(<<</>=) :: MonadState s m => LensLike' ((,) FilePath) s FilePath -> FilePath -> m FilePath infix 4 #

Add a path onto the end of a target of a `Lens` into your monad's state and return the old value.

When you do not need the result of the operation, (`</>=`) is more flexible.

(<.>=) :: MonadState s m => ASetter' s FilePath -> String -> m () infix 4 #

Modify the target(s) of a `Lens'`, `Iso'`, `Setter'` or `Traversal'` by adding an extension.

    >>> execState (both <.>= "txt") ("hello","world")
    ("hello.txt","world.txt")

    (<.>=) :: MonadState s m => Setter' s FilePath -> String -> m ()
    (<.>=) :: MonadState s m => Iso' s FilePath -> String -> m ()
    (<.>=) :: MonadState s m => Lens' s FilePath -> String -> m ()
    (<.>=) :: MonadState s m => Traversal' s FilePath -> String -> m ()

(<<.>=) :: MonadState s m => LensLike' ((,) FilePath) s FilePath -> String -> m FilePath infix 4 #

Add an extension onto the end of the target of a `Lens` into your monad's state and return the result.

    >>> evalState (_1 <<.>= "txt") ("hello","world")
    "hello.txt"

When you do not need the result of the operation, (`<.>=`) is more flexible.

(<<<.>=) :: MonadState s m => LensLike' ((,) FilePath) s FilePath -> String -> m FilePath infix 4 #

Add an extension onto the end of the target of a `Lens` into your monad's state and return the old value.

    >>> runState (_1 <<<.>= "txt") ("hello","world")
    ("hello",("hello.txt","world"))

When you do not need the old value, (`<.>=`) is more flexible.

# Lenses

basename :: Lens' FilePath FilePath #

A `Lens` for reading and writing to the basename

Note: This is not a legal `Lens` unless the outer `FilePath` has both a directory and filename component and the generated basenames are not null and contain no directory separators.

    >>> (basename .~ "filename" $ "path" </> "name.png") == "path" </> "filename.png"
    True

directory :: Lens' FilePath FilePath #

A `Lens` for reading and writing to the directory

Note: this is not a legal `Lens` unless the outer `FilePath` already has a directory component, and generated directories are not null.

    >>> (("long" </> "path" </> "name.txt") ^. directory) == "long" </> "path"
    True

extension :: Lens' FilePath FilePath #

A `Lens` for reading and writing to the extension

Note: This is not a legal `Lens`, unless you are careful to ensure that generated extension `FilePath` components are either null or start with `extSeparator` and do not contain any internal `extSeparator`s.

    >>> (extension .~ ".png" $ "path" </> "name.txt") == "path" </> "name.png"
    True

filename :: Lens' FilePath FilePath #

A `Lens` for reading and writing to the full filename

Note: This is not a legal `Lens`, unless you are careful to ensure that generated filename `FilePath` components are not null and do not contain any elements of `pathSeparators`s.

    >>> (filename .~ "name.txt" $ "path" </> "name.png") == "path" </> "name.txt"
    True