struct Path

Overview

A Path represents a filesystem path and allows path-handling operations such as querying its components as well as semantic manipulations.

A path is hierarchical and composed of a sequence of directory and file name elements separated by a special separator or delimiter. A root component, that identifies a file system hierarchy, may also be present. The name element that is farthest from the root of the directory hierarchy is the name of a file or directory. The other name elements are directory names. A Path can represent a root, a root and a sequence of names, or simply one or more name elements. A Path is considered to be an empty path if it consists solely of one name element that is empty or equal to ".". Accessing a file using an empty path is equivalent to accessing the default directory of the process.

Examples

Path["foo/bar/baz.cr"].parent    # => Path["foo/bar"]
Path["foo/bar/baz.cr"].basename  # => "baz.cr"
Path["./foo/../bar"].normalize   # => Path["bar"]
Path["~/bin"].expand(home: true) # => Path["/home/crystal/bin"]

For now, its methods are purely lexical, there is no direct filesystem access.

Path handling comes in different kinds depending on operating system:

# On POSIX system:
Path.new("foo", "bar", "baz.cr") == Path.posix("foo/bar/baz.cr")
# On Windows system:
Path.new("foo", "bar", "baz.cr") == Path.windows("foo\\bar\\baz.cr")

The main differences between Windows and POSIX paths:

Path.posix("/foo/./bar").normalize   # => Path.posix("/foo/bar")
Path.windows("/foo/./bar").normalize # => Path.windows("\\foo\\bar")

Path.posix("/foo").absolute?   # => true
Path.windows("/foo").absolute? # => false

Path.posix("foo") == Path.posix("FOO")     # => false
Path.windows("foo") == Path.windows("FOO") # => true

Included Modules

Defined in:

json/to_json.cr
path.cr
yaml/to_yaml.cr

Constant Summary

SEPARATORS = separators(Kind.native)

The file/directory separator characters of the current platform. {'/'} on POSIX, {'\\', '/'} on Windows.

Constructors

Instance Method Summary

Instance methods inherited from module Comparable(Path)

<(other : T) : Bool <, <=(other : T) <=, <=>(other : T) <=>, ==(other : T) ==, >(other : T) : Bool >, >=(other : T) >=, clamp(min, max)
clamp(range : Range) clamp

Instance methods inherited from struct Struct

==(other) : Bool ==, hash(hasher) hash, inspect(io : IO) : Nil inspect, pretty_print(pp) : Nil pretty_print, to_s(io : IO) : Nil to_s

Instance methods inherited from struct Value

==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==, dup dup

Instance methods inherited from class Object

! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash, in?(collection : Object) : Bool
in?(*values : Object) : Bool in?, inspect(io : IO) : Nil
inspect : String inspect, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil!(message)
not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String to_json, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil to_pretty_json, to_s(io : IO) : Nil
to_s : String to_s, to_yaml(io : IO) : Nil
to_yaml : String to_yaml, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

Class methods inherited from class Object

from_json(string_or_io, root : String)
from_json(string_or_io) from_json, from_yaml(string_or_io : String | IO) from_yaml

Constructor Detail

def self.[](parts : Enumerable) : Path #

Creates a new Path of native kind.

When compiling for a windows target, this is equal to Path.windows(), otherwise Path.posix is used.


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def self.[](name : String | Path, *parts) : Path #

Creates a new Path of native kind.

When compiling for a windows target, this is equal to Path.windows(), otherwise Path.posix is used.


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def self.home : Path #

Returns the path of the home directory of the current user.


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def self.new(ctx : YAML::ParseContext, node : YAML::Nodes::Node) #

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def self.new(name : String = "") : Path #

Creates a new Path of native kind.

When compiling for a windows target, this is equal to Path.windows(), otherwise Path.posix is used.


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def self.new(path : Path) : Path #

Creates a new Path of native kind.

When compiling for a windows target, this is equal to Path.windows(), otherwise Path.posix is used.


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def self.new(parts : Enumerable) : Path #

Creates a new Path of native kind.

When compiling for a windows target, this is equal to Path.windows(), otherwise Path.posix is used.


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def self.new(pull : JSON::PullParser) #

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def self.new(name : String | Path, *parts : String | Path) : Path #

Creates a new Path of native kind.

When compiling for a windows target, this is equal to Path.windows(), otherwise Path.posix is used.


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def self.posix(name : String = "") : Path #

Creates a new Path of POSIX kind.


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def self.posix(path : Path) : Path #

Creates a new Path of POSIX kind.


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def self.posix(parts : Enumerable) : Path #

Creates a new Path of POSIX kind.


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def self.posix(name : String | Path, *parts : String | Path) : Path #

Creates a new Path of POSIX kind.


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def self.windows(name : String = "") : Path #

Creates a new Path of Windows kind.


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def self.windows(path : Path) : Path #

Creates a new Path of Windows kind.


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def self.windows(parts : Enumerable) : Path #

Creates a new Path of Windows kind.


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def self.windows(name : String | Path, *parts : String | Path) : Path #

Creates a new Path of Windows kind.


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Instance Method Detail

def /(part : Path | String) : Path #

Appends the given part to this path and returns the joined path.

Path["foo"] / "bar" / "baz"     # => Path["foo/bar/baz"]
Path["foo/"] / Path["/bar/baz"] # => Path["foo/bar/baz"]

See #join(part) for details.


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def <=>(other : Path) #

Compares this path to other.

The comparison is performed strictly lexically: foo and ./foo are not treated as equal. Nor are paths of different kind. To compare paths semantically, they need to be normalized and converted to the same kind.

Path["foo"] <=> Path["foo"]               # => 0
Path["foo"] <=> Path["./foo"]             # => 1
Path["foo"] <=> Path["foo/"]              # => -1
Path.posix("foo") <=> Path.windows("foo") # => -1

Comparison is case-sensitive for POSIX paths and case-insensitive for Windows paths.

Path.posix("foo") <=> Path.posix("FOO")     # => 1
Path.windows("foo") <=> Path.windows("FOO") # => 0

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def ==(other : self) #

Returns true if this path is considered equivalent to other.

The comparison is performed strictly lexically: foo and ./foo are not treated as equal. Nor are paths of different kind. To compare paths semantically, they need to be normalized and converted to the same kind.

Path["foo"] == Path["foo"]               # => true
Path["foo"] == Path["./foo"]             # => false
Path["foo"] == Path["foo/"]              # => false
Path.posix("foo") == Path.windows("foo") # => false

Comparison is case-sensitive for POSIX paths and case-insensitive for Windows paths.

Path.posix("foo") == Path.posix("FOO")     # => false
Path.windows("foo") == Path.windows("FOO") # => true

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def absolute? : Bool #

Returns true if this path is absolute.

A POSIX path is absolute if it begins with a forward slash (#/). A Windows path is absolute if it begins with a drive letter and root (C:\) or with a UNC share (\\server\share\).


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def anchor : Path | Nil #

Returns the concatenation of #drive and #root.

Path["/etc/"].anchor                           # => Path["/"]
Path.windows("C:Program Files").anchor         # => Path.windows("C:")
Path.windows("C:\\Program Files").anchor       # => Path.windows("C:\\")
Path.windows("\\\\host\\share\\folder").anchor # => Path.windows("\\\\host\\share\\")

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def basename(suffix : String | Nil = nil) : String #

Returns the last component of this path.

If suffix is given, it is stripped from the end.

In case the last component is the empty string (i.e. the path has a trailing separator), the second to last component is returned. For a path that only consists of an anchor, or an empty path, the base name is equivalent to the full path.

Path["/foo/bar/file.cr"].basename # => "file.cr"
Path["/foo/bar/"].basename        # => "bar"
Path["/foo/bar/."].basename       # => "."
Path["/"].basename                # => "/"
Path[""].basename                 # => ""

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def dirname : String #

Returns all components of this path except the last one.

Path["/foo/bar/file.cr"].dirname # => "/foo/bar"

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def drive : Path | Nil #

Returns a path representing the drive component or nil if this path does not contain a drive.

See #anchor for the combination of drive and #root.

Path.windows("C:\\Program Files").drive       # => Path.windows("C:")
Path.windows("\\\\host\\share\\folder").drive # => Path.windows("\\\\host\\share")

NOTE Drives are only available for Windows paths. It can either be a drive letter (C:) or a UNC share (\\host\share).


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def drive_and_root : Tuple(String | Nil, String | Nil) #

Returns a tuple of #drive and #root as strings.


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def each_parent(&block : Path -> ) #

Yields each parent of this path beginning with the topmost parent.

Path["foo/bar/file.cr"].each_parent { |parent| puts parent }
# Path["."]
# Path["foo"]
# Path["foo/bar"]

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def each_part(& : String -> ) #

Yields each component of this path as a String.

Path.new("foo/bar/").each_part # yields: "foo", "bar"

See #parts for more examples.


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def each_part : Iterator(String) #

Returns an iterator over all components of this path.

parts = Path.new("foo/bar/").each_part
parts.next # => "foo"
parts.next # => "bar"
parts.next # => Iterator::Stop::INSTANCE

See #parts for more examples.


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def ends_with_separator? : Bool #

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def expand(base : Path | String = Dir.current, *, home : Path | String | Bool = false, expand_base = true) : Path #

Converts this path to an absolute path. Relative paths are referenced from the current working directory of the process (Dir.current) unless base is given, in which case it will be used as the reference path.

Path["foo"].expand                 # => Path["/current/path/foo"]
Path["~/foo"].expand(home: "/bar") # => Path["/bar/foo"]
Path["baz"].expand("/foo/bar")     # => Path["/foo/bar/baz"]

home specifies the home directory which ~ will expand to. "~" is expanded to the value passed to home. If it is false (default), home is not expanded. If true, it is expanded to the user's home directory (Path.home).

If expand_base is true, base itself will be expanded in Dir.current if it is not an absolute path. This guarantees the method returns an absolute path (assuming that Dir.current is absolute).


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def extension : String #

Returns the extension of this path, or an empty string if it has no extension.

Path["foo.cr"].extension     # => ".cr"
Path["foo"].extension        # => ""
Path["foo.tar.gz"].extension # => ".gz"

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def hash(hasher) #
Description copied from struct Struct

See Object#hash(hasher)


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def inspect(io : IO) #

Inspects this path to io.


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def join(parts : Enumerable) : Path #

Appends the given parts to this path and returns the joined path.

Path["foo"].join("bar", "baz")           # => Path["foo/bar/baz"]
Path["foo/"].join(Path["/bar/", "/baz"]) # => Path["foo/bar/baz"]
Path["/foo/"].join("/bar/", "/baz/")     # => Path["/foo/bar/baz/"]

Non-matching paths are implicitly converted to this path's kind.

Path.posix("foo/bar").join(Path.windows("baz\\baq")) # => Path.posix("foo/bar/baz/baq")
Path.windows("foo\\bar").join(Path.posix("baz/baq")) # => Path.windows("foo\\bar\\baz/baq")

See #join(part) for details.


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def join(part) : Path #

Appends the given part to this path and returns the joined path.

Path["foo"].join("bar")     # => Path["foo/bar"]
Path["foo/"].join("/bar")   # => Path["foo/bar"]
Path["/foo/"].join("/bar/") # => Path["/foo/bar/"]

Joining an empty string ("") appends a trailing path separator. In case the path already ends with a trailing separator, no additional separator is added.

Path["a/b"].join("")   # => Path["a/b/"]
Path["a/b/"].join("")  # => Path["a/b/"]
Path["a/b/"].join("c") # => Path["a/b/c"]

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def join(*parts) : Path #

Appends the given parts to this path and returns the joined path.

Path["foo"].join("bar", "baz")       # => Path["foo/bar/baz"]
Path["foo/"].join("/bar/", "/baz")   # => Path["foo/bar/baz"]
Path["/foo/"].join("/bar/", "/baz/") # => Path["/foo/bar/baz/"]

See #join(part) for details.


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def native? : Bool #

Returns true if this is a native path for the target platform.


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def normalize(*, remove_final_separator : Bool = true) : Path #

Removes redundant elements from this path and returns the shortest equivalent path by purely lexical processing. It applies the following rules iteratively until no further processing can be done:

  1. Replace multiple slashes with a single slash.
  2. Eliminate each . path name element (the current directory).
  3. Eliminate each .. path name element (the parent directory) preceded by a non-.. element along with the latter.
  4. Eliminate .. elements that begin a rooted path: that is, replace "/.." by "/" at the beginning of a path.

If the path turns to be empty, the current directory (".") is returned.

The returned path ends in a slash only if it is the root ("/", \, or C:\).

See also Rob Pike: Lexical File Names in Plan 9 or Getting Dot-Dot Right


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def parent : Path #

Returns the parent path of this path.

If the path is empty, it returns ".". If the path is rooted and in the top-most hierarchy, the root path is returned.

Path["foo/bar/file.cr"].parent # => Path["foo/bar"]
Path["foo"].parent             # => Path["."]
Path["/foo"].parent            # => Path["/"]
Path["/"].parent               # => Path["/"]
Path[""].parent                # => Path["."]
Path["foo/bar/."].parent       # => Path["foo/bar"]

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def parents : Array(Path) #

Returns all parent paths of this path beginning with the topmost path.

Path["foo/bar/file.cr"].parents # => [Path["."], Path["foo"], Path["foo/bar"]]

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def parts : Array(String) #

Returns the components of this path as an Array(String).

Path.new("foo/bar/").parts                   # => ["foo", "bar"]
Path.new("/Users/foo/bar.cr").parts          # => ["/", "Users", "foo", "bar.cr"]
Path.windows("C:\\Users\\foo\\bar.cr").parts # => ["C:\\", "Users", "foo", "bar.cr"]
Path.posix("C:\\Users\\foo\\bar.cr").parts   # => ["C:\\Users\\foo\\bar.cr"]

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def posix? : Bool #

Returns true if this is a POSIX path.


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def relative_to(base : Path | String) : Path #

Same as #relative_to but returns self if self can't be expressed as relative path to base.


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def relative_to?(base : Path) : Path | Nil #

Returns a relative path that is lexically equivalent to self when joined to base with an intervening separator.

The returned path is in normalized form.

That means with normalized paths base.join(target.relative_to(base)) is equivalent to target.

Returns nil if self cannot be expressed as relative to base or if knowing the current working directory would be necessary to resolve it. The latter can be avoided by expanding the paths first.


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def relative_to?(base : String) : Path | Nil #

Returns a relative path that is lexically equivalent to self when joined to base with an intervening separator.

The returned path is in normalized form.

That means with normalized paths base.join(target.relative_to(base)) is equivalent to target.

Returns nil if self cannot be expressed as relative to base or if knowing the current working directory would be necessary to resolve it. The latter can be avoided by expanding the paths first.


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def root : Path | Nil #

Returns the root path component of this path or nil if it is not rooted.

See #anchor for the combination of #drive and root.

Path["/etc/"].root                           # => Path["/"]
Path.windows("C:Program Files").root         # => nil
Path.windows("C:\\Program Files").root       # => Path.windows("\\")
Path.windows("\\\\host\\share\\folder").root # => Path.windows("\\")

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def sibling(name : Path | String) : Path #

Resolves path name in this path's parent directory.

Raises Path::Error if #parent is nil.


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def stem : String #

Returns the last component of this path without the extension.

This is equivalent to self.basename(self.extension).

Path["file.cr"].stem     # => "file"
Path["file.tar.gz"].stem # => "file.tar"
Path["foo/file.cr"].stem # => "file"

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def to_json(json : JSON::Builder) : Nil #

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def to_json_object_key : String #

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def to_kind(kind, *, mappings : Bool = true) : Path #

Converts this path to the given kind.

See #to_windows and #to_posix for details.

  • #to_native converts to the native path semantics.

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def to_native : Path #

Converts this path to a native path.

  • #to_kind performs a configurable conversion.

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def to_posix(*, mappings : Bool = true) : Path #

Converts this path to a POSIX path.

It returns a new instance with Kind::POSIX and all occurrences of Windows' backslash file separators (\\) replaced by forward slash (#/). If #posix? is true, this is a no-op.

Path.windows("foo/bar\\baz").to_posix # => Path.posix("foo/bar/baz")
Path.posix("foo/bar\\baz").to_posix   # => Path.posix("foo/bar\\baz")

When mappings is true (default), replacements for forbidden characters in Windows paths are substituted by the original characters when converting to a POSIX path. Originals are calculated by subtracting 0xF000 from the replacement codepoint. For example, the U+F05C becomes U+005C, the backslash character.

Path.windows("foo\uF05Cbar").to_posix(mappings: true)  # => Path.posix("foo\\bar")
Path.windows("foo\uF05Cbar").to_posix(mappings: false) # => Path.posix("foo\uF05Cbar")

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def to_s(io : IO) #

Appends the string representation of this path to io.


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def to_s : String #

Returns the string representation of this path.


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def to_uri : URI #

Returns a new URI with file scheme from this path.

A URI can only be created with an absolute path. Raises Path::Error if this path is not absolute.


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def to_windows(*, mappings : Bool = true) : Path #

Converts this path to a Windows path.

This creates a new instance with the same string representation but with Kind::WINDOWS. If #windows? is true, this is a no-op.

Path.posix("foo/bar").to_windows   # => Path.windows("foo/bar")
Path.windows("foo/bar").to_windows # => Path.windows("foo/bar")

When mappings is true (default), forbidden characters in Windows paths are substituted by replacement characters when converting from a POSIX path. Replacements are calculated by adding 0xF000 to their codepoint. For example, the backslash character U+005C becomes U+F05C.

Path.posix("foo\\bar").to_windows(mappings: true)  # => Path.windows("foo\uF05Cbar")
Path.posix("foo\\bar").to_windows(mappings: false) # => Path.windows("foo\\bar")
  • #to_posix performs the inverse conversion.
  • #to_kind performs a configurable conversion.

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def to_yaml(yaml : YAML::Nodes::Builder) : Nil #

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def windows? : Bool #

Returns true if this is a Windows path.


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