path-0.5.11: Support for well-typed paths

Copyright | © 2015–2016 FP Complete
License | BSD 3 clause
Maintainer | Chris Done <chrisdone@fpcomplete.com>
Stability | experimental
Portability | portable
Safe Haskell | None
Language | Haskell98

Path

Contents

- Types
- Parsing
- Constructors
- Operations
- Conversion

Description

Support for well-typed paths.

Synopsis

- data Path b t
- data Abs
- data Rel
- data File
- data Dir
- parseAbsDir :: MonadThrow m => FilePath -> m (Path Abs Dir)
- parseRelDir :: MonadThrow m => FilePath -> m (Path Rel Dir)
- parseAbsFile :: MonadThrow m => FilePath -> m (Path Abs File)
- parseRelFile :: MonadThrow m => FilePath -> m (Path Rel File)
- data PathParseException
- mkAbsDir :: FilePath -> Q Exp
- mkRelDir :: FilePath -> Q Exp
- mkAbsFile :: FilePath -> Q Exp
- mkRelFile :: FilePath -> Q Exp
- (</>) :: Path b Dir -> Path Rel t -> Path b t
- stripDir :: MonadThrow m => Path b Dir -> Path b t -> m (Path Rel t)
- isParentOf :: Path b Dir -> Path b t -> Bool
- parent :: Path Abs t -> Path Abs Dir
- filename :: Path b File -> Path Rel File
- dirname :: Path b Dir -> Path Rel Dir
- fileExtension :: Path b File -> String
- setFileExtension :: MonadThrow m => String -> Path b File -> m (Path b File)
- toFilePath :: Path b t -> FilePath
- fromAbsDir :: Path Abs Dir -> FilePath
- fromRelDir :: Path Rel Dir -> FilePath
- fromAbsFile :: Path Abs File -> FilePath
- fromRelFile :: Path Rel File -> FilePath

# Types

data Path b t #

Path of some base and type.

Internally is a string. The string can be of two formats only:

1. File format: `file.txt`, `foo/bar.txt`, `/foo/bar.txt`
2. Directory format: `foo/`, `/foo/bar/`

All directories end in a trailing separator. There are no duplicate path separators `//`, no `..`, no `./`, no `~/`, etc.

Instances

Eq (Path b t) # | String equality. The following property holds:
    show x == show y ≡ x == y
Methods (==) :: Path b t -> Path b t -> Bool # (/=) :: Path b t -> Path b t -> Bool #
Ord (Path b t) # | String ordering. The following property holds:
    show x `compare` show y ≡ x `compare` y
Methods compare :: Path b t -> Path b t -> Ordering # (<) :: Path b t -> Path b t -> Bool # (<=) :: Path b t -> Path b t -> Bool # (>) :: Path b t -> Path b t -> Bool # (>=) :: Path b t -> Path b t -> Bool # max :: Path b t -> Path b t -> Path b t # min :: Path b t -> Path b t -> Path b t #
Show (Path b t) # | Same as `toFilePath`. The following property holds:
    x == y ≡ show x == show y
Methods showsPrec :: Int -> Path b t -> ShowS # show :: Path b t -> String # showList :: [Path b t] -> ShowS #
FromJSON (Path Rel Dir) # |
Methods parseJSON :: Value -> Parser (Path Rel Dir) # parseJSONList :: Value -> Parser [Path Rel Dir] #
FromJSON (Path Rel File) # |
Methods parseJSON :: Value -> Parser (Path Rel File) # parseJSONList :: Value -> Parser [Path Rel File] #
FromJSON (Path Abs Dir) # |
Methods parseJSON :: Value -> Parser (Path Abs Dir) # parseJSONList :: Value -> Parser [Path Abs Dir] #
FromJSON (Path Abs File) # |
Methods parseJSON :: Value -> Parser (Path Abs File) # parseJSONList :: Value -> Parser [Path Abs File] #
ToJSON (Path b t) # |
Methods toJSON :: Path b t -> Value # toEncoding :: Path b t -> Encoding # toJSONList :: [Path b t] -> Value # toEncodingList :: [Path b t] -> Encoding #
NFData (Path b t) # |
Methods rnf :: Path b t -> () #

data Abs #

An absolute path.

Instances

FromJSON (Path Abs Dir) # |
Methods parseJSON :: Value -> Parser (Path Abs Dir) # parseJSONList :: Value -> Parser [Path Abs Dir] #
FromJSON (Path Abs File) # |
Methods parseJSON :: Value -> Parser (Path Abs File) # parseJSONList :: Value -> Parser [Path Abs File] #

data Rel #

A relative path; one without a root. Note that a `.` as well as any path starting with a `..` is not a valid relative path. In other words, a relative path is always strictly under the directory tree to which it is relative.

Instances

FromJSON (Path Rel Dir) # |
Methods parseJSON :: Value -> Parser (Path Rel Dir) # parseJSONList :: Value -> Parser [Path Rel Dir] #
FromJSON (Path Rel File) # |
Methods parseJSON :: Value -> Parser (Path Rel File) # parseJSONList :: Value -> Parser [Path Rel File] #

data File #

A file path.

Instances

FromJSON (Path Rel File) # |
Methods parseJSON :: Value -> Parser (Path Rel File) # parseJSONList :: Value -> Parser [Path Rel File] #
FromJSON (Path Abs File) # |
Methods parseJSON :: Value -> Parser (Path Abs File) # parseJSONList :: Value -> Parser [Path Abs File] #

data Dir #

A directory path.

Instances

FromJSON (Path Rel Dir) # |
Methods parseJSON :: Value -> Parser (Path Rel Dir) # parseJSONList :: Value -> Parser [Path Rel Dir] #
FromJSON (Path Abs Dir) # |
Methods parseJSON :: Value -> Parser (Path Abs Dir) # parseJSONList :: Value -> Parser [Path Abs Dir] #

# Parsing

parseAbsDir :: MonadThrow m => FilePath -> m (Path Abs Dir) #

Convert an absolute `FilePath` to a normalized absolute dir `Path`.

Throws: `PathParseException` when the supplied path:

- is not an absolute path
- contains a `..` anywhere in the path
- is not a valid path (See `isValid`)

parseRelDir :: MonadThrow m => FilePath -> m (Path Rel Dir) #

Convert a relative `FilePath` to a normalized relative dir `Path`.

Throws: `PathParseException` when the supplied path:

- is not a relative path
- is any of `""`, `.` or `..`
- contains `..` anywhere in the path
- is not a valid path (See `isValid`)

parseAbsFile :: MonadThrow m => FilePath -> m (Path Abs File) #

Convert an absolute `FilePath` to a normalized absolute file `Path`.

Throws: `PathParseException` when the supplied path:

- is not an absolute path
- has a trailing path separator
- contains `..` anywhere in the path
- ends in `/.`
- is not a valid path (See `isValid`)

parseRelFile :: MonadThrow m => FilePath -> m (Path Rel File) #

Convert a relative `FilePath` to a normalized relative file `Path`.

Throws: `PathParseException` when the supplied path:

- is not a relative path
- has a trailing path separator
- is `""`, `.` or `..`
- contains `..` anywhere in the path
- is not a valid path (See `isValid`)

data PathParseException #

Exception when parsing a location.

Instances

Show PathParseException # |
Methods showsPrec :: Int -> PathParseException -> ShowS # show :: PathParseException -> String # showList :: [PathParseException] -> ShowS #
Exception PathParseException # |
Methods toException :: PathParseException -> SomeException # fromException :: SomeException -> Maybe PathParseException # displayException :: PathParseException -> String #

# Constructors

mkAbsDir :: FilePath -> Q Exp #

Make a 'Path Abs Dir'.

Remember: due to the nature of absolute paths this (e.g. `/home/foo`) may compile on your platform, but it may not compile on another platform (Windows).

mkRelDir :: FilePath -> Q Exp #

Make a 'Path Rel Dir'.

mkAbsFile :: FilePath -> Q Exp #

Make a 'Path Abs File'.

Remember: due to the nature of absolute paths this (e.g. `/home/foo`) may compile on your platform, but it may not compile on another platform (Windows).

mkRelFile :: FilePath -> Q Exp #

Make a 'Path Rel File'.

# Operations

(</>) :: Path b Dir -> Path Rel t -> Path b t #

Append two paths.

The following cases are valid and the equalities hold:

    $(mkAbsDir x) </> $(mkRelDir y) = $(mkAbsDir (x ++ "/" ++ y))

    $(mkAbsDir x) </> $(mkRelFile y) = $(mkAbsFile (x ++ "/" ++ y))

    $(mkRelDir x) </> $(mkRelDir y) = $(mkRelDir (x ++ "/" ++ y))

    $(mkRelDir x) </> $(mkRelFile y) = $(mkRelFile (x ++ "/" ++ y))

The following are proven not possible to express:

    $(mkAbsFile …) </> x

    $(mkRelFile …) </> x

    x </> $(mkAbsFile …)

    x </> $(mkAbsDir …)

stripDir :: MonadThrow m => Path b Dir -> Path b t -> m (Path Rel t) #

Strip directory from path, making it relative to that directory. Throws `Couldn'tStripPrefixDir` if directory is not a parent of the path.

The following properties hold:

    stripDir x (x </> y) = y

Cases which are proven not possible:

    stripDir (a :: Path Abs …) (b :: Path Rel …)

    stripDir (a :: Path Rel …) (b :: Path Abs …)

In other words the bases must match.

isParentOf :: Path b Dir -> Path b t -> Bool #

Is p a parent of the given location? Implemented in terms of `stripDir`. The bases must match.

The following properties hold:

    not (x isParentOf x)

    x isParentOf (x </> y)

parent :: Path Abs t -> Path Abs Dir #

Take the absolute parent directory from the absolute path.

The following properties hold:

    parent (x </> y) == x

On the root, getting the parent is idempotent:

    parent (parent "/") = "/"

filename :: Path b File -> Path Rel File #

Extract the file part of a path.

The following properties hold:

    filename (p </> a) == filename a

dirname :: Path b Dir -> Path Rel Dir #

Extract the last directory name of a path.

The following properties hold:

    dirname (p </> a) == dirname a

fileExtension :: Path b File -> String #

Get extension from given file path.

Since: 0.5.11

setFileExtension #

Arguments

:: MonadThrow m |
=> String | Extension to set
-> Path b File | Old file name
-> m (Path b File) | New file name with the desired extension

Replace/add extension to given file path. Throws if the resulting filename does not parse.

Since: 0.5.11

# Conversion

toFilePath :: Path b t -> FilePath #

Convert to a `FilePath` type.

All directories have a trailing slash, so if you want no trailing slash, you can use `dropTrailingPathSeparator` from the filepath package.

fromAbsDir :: Path Abs Dir -> FilePath #

Convert absolute path to directory to `FilePath` type.

fromRelDir :: Path Rel Dir -> FilePath #

Convert relative path to directory to `FilePath` type.

fromAbsFile :: Path Abs File -> FilePath #

Convert absolute path to file to `FilePath` type.

fromRelFile :: Path Rel File -> FilePath #

Convert relative path to file to `FilePath` type.