Path

The Path module provides utility functions for manipulating file system paths as strings: joining segments, splitting them apart, normalizing, checking existence and converting between absolute and relative forms.

Path is a static class — it is never instantiated. All members are accessed directly on Path.

All methods of Path are static. It cannot be instantiated.

Path();   // error: cannot take instance of static class

Path is purely string-based: it does not read the file system except for the isFileExist and isDirExist helpers. All other methods work on the textual form of the path and follow the conventions of the underlying operating system (e.g. \ on Windows, / on Unix).

Reference

Static methods

Method	Signature	Return Type	Description
join	join(base : string, ...parts : string)	string	Joins one or more path segments into a single path string. Requires at least one argument.
isFileExist	isFileExist(path : string)	bool	Returns true if path exists on disk and refers to a regular file, otherwise false.
isDirExist	isDirExist(path : string)	bool	Returns true if path exists on disk and refers to a directory, otherwise false.
isAbsolute	isAbsolute(path : string)	bool	Returns true if path is an absolute path according to the current OS.
getFileName	getFileName(path : string)	string or null	Returns the last segment of path (file or directory name). Returns null if the path has no name component.
getParent	getParent(path : string)	string or null	Returns the parent path of path, or null if it has no parent.
getRoot	getRoot(path : string)	string or null	Returns the root component of path (e.g. C:\ on Windows, / on Unix), or null if the path has no root.
getNameCount	getNameCount(path : string)	int	Returns the number of name elements in path (the root is not counted).
subPath	subPath(path : string, start : int, end : int)	string	Returns a relative path consisting of the name elements in the range [start, end). Indices are zero-based.
getExtension	getExtension(path : string)	string or null	Returns the file extension of the last segment, including the leading dot (e.g. ".txt"). Returns null if there is no extension.
normalize	normalize(path : string)	string	Returns path with redundant elements (. and ..) removed.
resolve	resolve(base : string, other : string)	string	Resolves other against base. If other is absolute it is returned as-is; otherwise it is appended to base.
relativize	relativize(base : string, target : string)	string	Returns the relative path from base to target. Both paths must be either absolute or both relative.

Errors

The following situations raise a runtime error:

• join is called with no arguments.
• Any string argument is missing or has the wrong type.
• subPath is called with start < 0, end < 0, start >= end, or end > getNameCount(path).
• relativize is called with one absolute and one relative path.

You can handle these with try / catch.

Examples

Joining segments

let p = Path.join("project", "src", "main.ys");
IO.stdout.writeln(p);
// Windows -> project\src\main.ys
// Unix    -> project/src/main.ys

Inspecting a path

let file = Path.join("home", "yagiz", "notes.txt");

IO.stdout.writeln(Path.getFileName(file));   // notes.txt
IO.stdout.writeln(Path.getParent(file));     // home\yagiz
IO.stdout.writeln(Path.getExtension(file));  // .txt
IO.stdout.writeln(__str(Path.getNameCount(file)));  // 3

Absolute vs relative

IO.stdout.writeln(Path.isAbsolute("C:\\Users\\me"));  // true
IO.stdout.writeln(Path.isAbsolute("src/main.ys"));    // false

IO.stdout.writeln(Path.getRoot("C:\\Users\\me"));     // C:\
IO.stdout.writeln(Path.getRoot("src/main.ys"));       // null

Existence checks

if Path.isFileExist("config.json") then do
    IO.stdout.writeln("Config found.");
end

if !Path.isDirExist("logs") then do
    IO.stdout.writeln("Logs directory is missing.");
end

Normalize, resolve, relativize

IO.stdout.writeln(Path.normalize("a/b/../c/./d"));
// -> a\c\d  (or a/c/d on Unix)

IO.stdout.writeln(Path.resolve("project/src", "main.ys"));
// -> project\src\main.ys

IO.stdout.writeln(Path.resolve("project/src", "/etc/hosts"));
// -> /etc/hosts   (absolute "other" replaces base)

IO.stdout.writeln(Path.relativize("project/src", "project/src/main.ys"));
// -> main.ys

Slicing path segments

let p = "project/src/ysharp/util/Path.java";

IO.stdout.writeln(Path.subPath(p, 0, 2));   // project\src
IO.stdout.writeln(Path.subPath(p, 2, 4));   // ysharp\util