BatPathGen.PathType
All implementations of Path
functionality have this module type.
Type of strings used. In case of Path
.OfRope it is Rope
.t and in Path
.OfString module it is string
.
module OperatorLift : sig ... end
Convenience operator for lifting primitive strings to ustring
type.
type t = ustring list
A type for storing paths. It is reversed list of names. In case of absolute path, the last element of the list is empty string (Windows: empty or letter-colon; details below). Empty list represents empty relative path.
Examples: ["a";"b";"c"]
is c/b/a (relative path); ["d";"e";""]
stays for /e/d (absolute path).
All examples here and below are given for ustring
=string
case for clarity. To have the code working with other string types, one should prepend the !!
operator (OperatorLift.(!!)
) to all string literals.
There are two infix operators provided to allow to write expressions in natural order. For example, to build a path using PathType.Operators.(/:)
one can write:
base_dir/:"bar"
instead of "bar"::base_dir
However it may be sometimes inevitable to write components in reverse, for example:
let whose_readme = function "README"::app::"doc"::"share"::_ -> Some app | _ -> None
Windows: Windows absolute paths start with "\\" or with drive letter. Use following representation:
Path.root/:"."/:"pipe" = ["pipe";".";""]
for "\\.\pipe"["C:"]/:"foo" = ["foo";"C:"]
for "C:\foo"In principle the first type of paths has broader range of allowed characters, but this implementation applies more strict rules to both (default_validator
).
val is_relative : t -> bool
val is_absolute : t -> bool
val root : t
Root of the filesystem ([""]
). It is minimal absolute path. Below it is called 'empty'. However it yields "/" or "\\" when converted to a string.
Windows: This path (root and nothing more) is meaningless, but for simplicity it is considered valid here. To create absolute path starting with drive letter, construct the list explicitly (as in ["C:"]/:"foo"
). A path consisting of drive letter only is also called 'empty' here.
Alternative name for Operators.(/:)
Alternative name for Operators.(//@)
module Operators : sig ... end
Infix operators for path construction. They are in separate module, so one can open Path.Operators
to use them.
module Infix : sig ... end
As other Operators modules in batteries are named "Infix" we provide Infix as well. This is a mere copy of Operators.
Consumes single dots where possible, e.g.:
normalize ([".."]/:"foo"/:"."/:"bar"/:"sub1"/:".."/:"sub2") = [".."]/:"foo"/:"bar"/:"sub1"/:".."/:"sub2"
When a directory structure contains links, it can be not pefectly pure tree. Then meaing of the ".." symbol depends on the real nature of parent of what is denoted by the name that preceded the ".." symbol. This symbol cannot be resolved for a graph traversal case when dealing with abstract paths only.
Windows: If single dot is next to root, it is preserved.
Consumes single dots and applies double dots where possible, e.g.:
normalize ([".."]/:"foo"/:"."/:"bar"/:"sub1"/:".."/:"sub2") = [".."]/:"foo"/:"bar"/:"sub2"
This normalization is useful when dealing with paths that describe locations in a tree and the ".." symbol always points to the only parent of what precedes this symbol.
Windows: If single dot is next to root, it is preserved.
belongs base sub
is true
when sub
descends from base
, i.e. base
is a prefix of sub
. If base
=sub
the function returns true
. It is otherwise false
. Both arguments must be absolute paths or both relative.
If both arguments have a root portion with drive letter and these letters are different, belongs base sub
returns false.
relative_to_any base sub
returns relative path rel
such that normalize (base/:rel) = normalize sub
, i.e. common base is stripped and ".." are added if necessary. Both arguments must be absolute paths or both relative.
This function normalizes base
and sub
before calculation of the relative path.
Windows: If base
and sub
are absolute, they must have the same root element: have the same drive letter or both starting with root
(i.e. ""
is the last element of the list). Exceptionally it is possible to get an absolute path as a result if drive letter is in sub
but not as a root element (e .g. base = root/:"bar"
and sub = root/:bar//@(["C:"]/:"foo"
).
relative_to_parent parent sub
returns relative path rel
such that (normalize parent)/:rel = normalize sub
. It is checked if sub
is really a descendant of parent
. Both arguments must be absolute paths or both relative.
This function normalizes base
and sub
before calculation of the relative path.
Windows: Exceptionally it is possible to get an absolute path as a result if drive letter is in sub
but not as a root element (e .g. base = root/:"bar"
and sub = root/:bar//@(["C:"]/:"foo")
).
Raised by PathType.of_string
, PathType.append
and PathType.Operators.(/:)
when used validator finds illegal character.
type validator = ustring -> bool
Validators should check if all characters of given string can be used in a name (path component). Return true if the name is valid. Return false if illegal character is found.
If a name should be rejected for some other reason, user defined validator may raise an exception.
Forward slash and code zero are considered invalid.
Windows: Invalid characters are *?:\/<> and all with code <32. Exception: the function PathType.of_string
doesn't use validator against drive letter with colon.
Convert to the chosen ustring
type. Empty relative path is converted to "." (single dot).
Windows: backslash is used as a separator and double backslash for root. If the path is only a drive letter (empty absolute path) trailing backslash is added (e.g. to_string ["C:"] = "C:\"
).
val to_string : t -> string
Convert to type primitive string with UTF-8 content. The string is built in the same way as by to_ustring
function.
Parse path in a given string. Any number of consecutive separators collapse ("a//b" becomes "a/b"). Path.default_validator
is applied to each resulting name.
Windows: both slashes '\' and '/' are accepted as separators. Paths of the 'semi-relative' form "C:foo\bar" are not recognized. For example "C:" string is parsed as ["C:"]
which has different meaning (see to_string
).
These functions do not accept empty paths, i.e. []
, [""]
or ["C:"]
.
Returns name of the object the pathname points to, i.e. name (foo/:bar) = bar
map_name fu path
returns path
with the name replaced by fu (
PathType.name
path)
.
Example: map_name (fun nn -> nn ^ ".backup") (["foo"]/:"bar") = ["foo"]/:"bar.backup"
PathType.default_validator
is applied to new name.
Returns extension of the name of the object the pathname points to. Examples:
ext ["aa.bb"] = Some "bb"
ext ["aa."] = Some ""
ext ["aa"] = None
ext [".hidden"] = Some "hidden"
(!)
Extension begins where the rightmost dot in the name is found. If the name ends with a dot, the extension is empty and Some ""
is returned. If there is no extension (no dot) the function returns None
.
@example "Count unfinished music downloads (files ending with '.ogg.part')."
let count_music_parts download_dir =
let files = Directory.files download_dir in
let check file =
match Path.ext file with
| Some "part" -> ((Path.ext (Path.name_core file)) = "ogg")
| _ -> false
in
let music_parts = List.filter check files in
List.length music_parts
map_ext fu path
returns path
but with the name with extension given by fu (
PathType.ext
path)
. If fu
returns Some _
, the original extension may be replaced (when Some ext
is passed to fu
) or new added (when fu
gets None
). In case fu
returns None
, the extension is removed (if exists).
@example "A name for file being encoded in a new format."
let pngname file = map_ext (function Some _ | None -> Some "png") file
let new_bar = pngname (["foo"]/:"bar.jpeg") (* = ["foo"]/:"bar.png" *)
PathType.default_validator
is applied to the resulting name.
The replacement string returned by the mapping function fu
can contain dots. Consequently, this string doesn't need to be an extension as defined by the ext
function. Consider for example:
let before = foo/:"bar.mli"
let replacement = "mli.off"
let ext_before = Path.ext before (* = Some "mli" *)
let after = Path.map_ext (fun _ -> Some replacement) before (* = foo/:"bar.mli.off" *)
let ext_after = Path.ext after (* = Some "off" *)
Note the difference between replacement
and ext_after
! (map_ext fu)
is idempotent only if fu
always returns Some _
. Otherwise it can remove the extension, possibly exposing part of the name that becomes the new extension.
Windows: If fu
returns Some ""
(to make a name with trailing period) map_ext
returns a path that shouldn't be passed to the operating system (it is invalid).
Returns part of the name to the left of rightmost dot. Returns empty string if the name starts with a dot.
@example "Label for a piece of GUI in which a file is edited."
let tab_label modified file =
let text = (if modified then "*" else "") ^ (Path.name_core file) in
GMisc.label ~text ()
A path
can be represented by the following triple: (Path.parent path, Path.name_core path, Path.ext path)
val split : t -> components
Dissect the path to its components (parent path, core part of name and possibly an extension).
Resulting name_core
string can be empty. For example, Path.split (Path.root/:"home"/:"user"/:".bashrc")
equals (Path.root/:"home"/:"user", "", Some "bashrc")
.
val join : components -> t
Create a path from given components.
val map : (components -> components) -> t -> t
Map a path through a function that operates on separate components.
Return drive letter of the given absolute path.
Windows: drive_letter abs
returns None
if abs
is simple absolute path (i.e. begins with a separator), otherwise the root element of abs
consists of a letter ch
with a colon - in this case Some ch
is returned.
Other systems: Returns None
on all absolute paths.
@example "(Windows only) Are the locations on the same partition?"
let can_move_quickly ~path_from ~path_to =
(drive_letter path_from) = (drive_letter path_to)