feat(stdlib): add pathlib module bindings (#276)

* feat(stdlib): add pathlib module bindings with 36 tests

Adds F# bindings for Python's pathlib.Path class:
- Path construction (single string and multi-segment)
- Properties: name, stem, suffix, suffixes, parent, parents, parts, root, anchor, drive
- Path arithmetic: / operator (string and Path), joinpath
- Pure transformations: with_name, with_stem, with_suffix, as_posix, as_uri
- I/O predicates: exists, is_file, is_dir, is_symlink, is_mount, is_absolute
- I/O operations: resolve, relative_to, read_text, read_bytes, write_text, write_bytes
- Directory operations: mkdir, mkdir_p, rmdir, iterdir, glob, rglob
- File operations: unlink, rename, replace, expanduser
- Static factories: Path.cwd, Path.home
- is_relative_to (3.9+)

Includes 36 tests covering construction, properties, path arithmetic,
transformations, predicates, file round-trips, and directory operations.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* fix(pathlib): make Path constructor emit positional args

Fable emits primary-ctor parameters as Python kwargs, but
pathlib.Path.__init__ does not accept `path=` as a keyword, breaking
27 tests with `TypeError: PurePath.__init__() got an unexpected
keyword argument 'path'`. Switch to a no-arg primary ctor and declare
the string and varargs ctors via [<Emit>] so emission stays
positional. Also relax suffixes/parents/parts to `seq<_>` to match the
underlying tuple/list/_PathParents return types, and wrap the byte
fixture in builtins.bytes so write_bytes receives a real bytes object
instead of a fable.UInt8Array.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* style: restore indentation on Pathlib.fs/TestPathlib.fs lines

Lost during the merge conflict resolution.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Dag Brattli <dag@brattli.net>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: 4 people

src/Fable.Python.fsproj

@@ -28,6 +28,7 @@
     <Compile Include="stdlib/Itertools.fs" />
     <Compile Include="stdlib/Datetime.fs" />
     <Compile Include="stdlib/Functools.fs" />
+    <Compile Include="stdlib/Pathlib.fs" />
     <Compile Include="stdlib/Regex.fs" />
     <Compile Include="stdlib/Queue.fs" />
     <Compile Include="stdlib/String.fs" />

src/stdlib/Pathlib.fs

@@ -0,0 +1,269 @@
+/// Type bindings for Python pathlib module: https://docs.python.org/3/library/pathlib.html
+module Fable.Python.Pathlib
+
+open System
+open Fable.Core
+
+// fsharplint:disable MemberNames
+
+/// Represents a filesystem path on the current OS (POSIX or Windows).
+/// Paths are immutable; operations return new Path instances.
+///
+/// `Path()` represents the current directory (`.`). For multi-segment construction
+/// use the `/` operator (`Path "a" / "b" / "c"`) or `joinpath`.
+/// See https://docs.python.org/3/library/pathlib.html#pathlib.Path
+[<Import("Path", "pathlib")>]
+type Path() =
+    /// Construct a Path from a single string segment.
+    [<Emit("Path($0)")>]
+    new(path: string) = Path()
+
+    /// Construct a Path by joining multiple path segments.
+    /// Equivalent to ``Path(parts[0]) / parts[1] / …``.
+    [<Emit("Path($0...)")>]
+    new([<ParamArray>] paths: string[]) = Path()
+
+    // -------------------------------------------------------------------------
+    // Properties
+    // -------------------------------------------------------------------------
+
+    /// The final path component (file or directory name).
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.name
+    member _.name: string = nativeOnly
+
+    /// The final path component without its last suffix (file extension).
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.stem
+    member _.stem: string = nativeOnly
+
+    /// The last file extension of the final component (e.g. ".py"), or "" if none.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.suffix
+    member _.suffix: string = nativeOnly
+
+    /// All file extensions of the final component (e.g. [".tar"; ".gz"]).
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.suffixes
+    member _.suffixes: string seq = nativeOnly
+
+    /// The logical parent of the path (directory containing this path).
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.parent
+    member _.parent: Path = nativeOnly
+
+    /// Immutable sequence of the logical ancestors of the path.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.parents
+    member _.parents: Path seq = nativeOnly
+
+    /// The path's components as a tuple of strings.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.parts
+    member _.parts: string seq = nativeOnly
+
+    /// The root component of the path (e.g. "/" on POSIX), or "".
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.root
+    member _.root: string = nativeOnly
+
+    /// The concatenation of drive and root (e.g. "/" or "C:\\"), or "".
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.anchor
+    member _.anchor: string = nativeOnly
+
+    /// The drive letter or name (relevant on Windows), or "".
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.drive
+    member _.drive: string = nativeOnly
+
+    // -------------------------------------------------------------------------
+    // Path arithmetic
+    // -------------------------------------------------------------------------
+
+    /// Return a new Path by appending a child string segment.
+    /// This mirrors Python's ``path / "child"`` operator.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.__truediv__
+    [<Emit("$0 / $1")>]
+    static member (/) (left: Path, right: string) : Path = nativeOnly
+
+    /// Return a new Path by appending another Path.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.__truediv__
+    [<Emit("$0 / $1")>]
+    static member (/) (left: Path, right: Path) : Path = nativeOnly
+
+    /// Join one or more path segments to this path and return the result.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.joinpath
+    [<Emit("$0.joinpath($1...)")>]
+    member _.joinpath([<ParamArray>] parts: string[]) : Path = nativeOnly
+
+    // -------------------------------------------------------------------------
+    // Tests (pure — no I/O)
+    // -------------------------------------------------------------------------
+
+    /// Return True if the path is absolute (has both a root and, if applicable, a drive).
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.is_absolute
+    member _.is_absolute() : bool = nativeOnly
+
+    /// Return True if this path is relative to other (3.9+).
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.is_relative_to
+    member _.is_relative_to(other: Path) : bool = nativeOnly
+
+    /// Return True if this path is relative to the string path other (3.9+).
+    [<Emit("$0.is_relative_to($1)")>]
+    member _.is_relative_to(other: string) : bool = nativeOnly
+
+    // -------------------------------------------------------------------------
+    // Transformations (pure — no I/O)
+    // -------------------------------------------------------------------------
+
+    /// Return a new path with the name component replaced.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.with_name
+    member _.with_name(name: string) : Path = nativeOnly
+
+    /// Return a new path with the stem component replaced (3.9+).
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.with_stem
+    member _.with_stem(stem: string) : Path = nativeOnly
+
+    /// Return a new path with the suffix component replaced.
+    /// Pass "" to remove the suffix.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.with_suffix
+    member _.with_suffix(suffix: string) : Path = nativeOnly
+
+    /// Return a string representation of the path.
+    /// Equivalent to Python's ``str(path)``.
+    [<Emit("str($0)")>]
+    member _.str() : string = nativeOnly
+
+    /// Return the path as a POSIX string (forward slashes).
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.as_posix
+    member _.as_posix() : string = nativeOnly
+
+    /// Return the path as a URI (file:// scheme). Only absolute paths are supported.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.as_uri
+    member _.as_uri() : string = nativeOnly
+
+    // -------------------------------------------------------------------------
+    // I/O queries
+    // -------------------------------------------------------------------------
+
+    /// Return True if the path points to an existing filesystem entry.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.exists
+    member _.exists() : bool = nativeOnly
+
+    /// Return True if the path points to a regular file (follows symlinks).
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.is_file
+    member _.is_file() : bool = nativeOnly
+
+    /// Return True if the path points to a directory (follows symlinks).
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.is_dir
+    member _.is_dir() : bool = nativeOnly
+
+    /// Return True if the path points to a symbolic link.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.is_symlink
+    member _.is_symlink() : bool = nativeOnly
+
+    /// Return True if the path is a mount point.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.is_mount
+    member _.is_mount() : bool = nativeOnly
+
+    // -------------------------------------------------------------------------
+    // I/O operations
+    // -------------------------------------------------------------------------
+
+    /// Make the path absolute and resolve any symlinks or ``..`` components.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.resolve
+    member _.resolve() : Path = nativeOnly
+
+    /// Make the path relative to other, raising ValueError if impossible.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.relative_to
+    member _.relative_to(other: Path) : Path = nativeOnly
+
+    /// Make the path relative to a string path.
+    [<Emit("$0.relative_to($1)")>]
+    member _.relative_to(other: string) : Path = nativeOnly
+
+    /// Return the decoded contents of the file as a string (UTF-8 by default).
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.read_text
+    member _.read_text() : string = nativeOnly
+
+    /// Return the decoded contents of the file using the given encoding.
+    [<Emit("$0.read_text(encoding=$1)")>]
+    member _.read_text(encoding: string) : string = nativeOnly
+
+    /// Return the binary contents of the file as a bytes object.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.read_bytes
+    member _.read_bytes() : byte[] = nativeOnly
+
+    /// Write a string to the file, returning the number of characters written.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.write_text
+    [<Emit("$0.write_text($1)")>]
+    member _.write_text(data: string) : int = nativeOnly
+
+    /// Write a string to the file with the given encoding.
+    [<Emit("$0.write_text($1, encoding=$2)")>]
+    member _.write_text(data: string, encoding: string) : int = nativeOnly
+
+    /// Write binary data to the file, returning the number of bytes written.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.write_bytes
+    member _.write_bytes(data: byte[]) : int = nativeOnly
+
+    /// Iterate over the directory contents, yielding Path objects.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.iterdir
+    member _.iterdir() : Path seq = nativeOnly
+
+    /// Glob the given relative pattern in the directory, returning matching paths.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.glob
+    member _.glob(pattern: string) : Path seq = nativeOnly
+
+    /// Like glob() but descends into sub-directories recursively.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.rglob
+    member _.rglob(pattern: string) : Path seq = nativeOnly
+
+    /// Create this directory. Raises FileExistsError if it already exists.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.mkdir
+    member _.mkdir() : unit = nativeOnly
+
+    /// Create this directory with options.
+    /// parents=true creates any missing parent directories.
+    /// exist_ok=true suppresses FileExistsError.
+    [<Emit("$0.mkdir(mode=$1, parents=$2, exist_ok=$3)")>]
+    member _.mkdir(mode: int, parents: bool, exist_ok: bool) : unit = nativeOnly
+
+    /// Create this directory and all missing parents (equivalent to ``mkdir -p``).
+    [<Emit("$0.mkdir(parents=True, exist_ok=True)")>]
+    member _.mkdir_p() : unit = nativeOnly
+
+    /// Remove this directory. The directory must be empty.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.rmdir
+    member _.rmdir() : unit = nativeOnly
+
+    /// Remove this file (or symbolic link). Raises FileNotFoundError if missing.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.unlink
+    member _.unlink() : unit = nativeOnly
+
+    /// Remove this file; if missing_ok is true, no error is raised.
+    [<Emit("$0.unlink(missing_ok=$1)")>]
+    member _.unlink(missing_ok: bool) : unit = nativeOnly
+
+    /// Rename the file or directory to target, returning the new Path.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.rename
+    member _.rename(target: Path) : Path = nativeOnly
+
+    /// Rename the file or directory to a string target, returning the new Path.
+    [<Emit("$0.rename($1)")>]
+    member _.rename(target: string) : Path = nativeOnly
+
+    /// Rename to target, overwriting any existing destination.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.replace
+    member _.replace(target: Path) : Path = nativeOnly
+
+    /// Rename to a string target, overwriting any existing destination.
+    [<Emit("$0.replace($1)")>]
+    member _.replace(target: string) : Path = nativeOnly
+
+    /// Expand the ``~`` user home directory shortcut.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.expanduser
+    member _.expanduser() : Path = nativeOnly
+
+    // -------------------------------------------------------------------------
+    // Static factory methods
+    // -------------------------------------------------------------------------
+
+    /// Return a new Path representing the current working directory.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.cwd
+    static member cwd() : Path = nativeOnly
+
+    /// Return a new Path representing the user's home directory.
+    /// See https://docs.python.org/3/library/pathlib.html#pathlib.Path.home
+    static member home() : Path = nativeOnly

test/Fable.Python.Test.fsproj

@@ -34,6 +34,7 @@
     <Compile Include="TestTime.fs" />
     <Compile Include="TestString.fs" />
     <Compile Include="TestDatetime.fs" />
+    <Compile Include="TestPathlib.fs" />
     <Compile Include="TestRegex.fs" />
     <Compile Include="TestPydantic.fs" />
     <Compile Include="TestFastAPI.fs" />