Add unix-listen for Unix domain socket server support

Message

Adds native unix-listen function (C + Scheme wrapper) to sigil-socket, enabling creation of listening Unix domain sockets. Removes stale socket files before binding. Reuses tcp-accept for connections. Includes tests.

Also adds test output grep tip to CLAUDE.md.

Changed

 src/sigil/socket.sgl | 14 ++++++++++++++
 test/test-socket.sgl | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 66 insertions(+), 1 deletion(-)

Diff

src/sigil/socket.sglmodified

@@ -48,6 +48,7 @@

;; Unix domain sockets

unix-connect

+51

unix-listen

;; UDP operations

udp-socket

@@ -282,6 +283,19 @@

283

(define-native (unix-connect path)

284

(: string? -> (maybe socket?)))

285

+286

;;; Create a listening Unix domain socket.

+287

;;;

+288

;;; Binds to the specified path and begins listening for connections.

+289

;;; Removes any stale socket file at the path before binding.

+290

;;; Use `tcp-accept` to accept incoming connections.

+291

;;; Not available on Windows.

+292

;;;

+293

;;; ```scheme

+294

;;; (unix-listen "/tmp/my-server.sock") ; => #<socket>

+295

;;; ```

+296

(define-native (unix-listen path)

+297

(: string? -> (maybe socket?)))

+298

299

;; ========== Higher-Level Utilities ==========

300

301

;;; Connect to a TCP server, call proc with the socket, then close it.

test/test-socket.sglmodified

@@ -1,5 +1,6 @@

(import (sigil test)

−2

(sigil socket))

(sigil socket)

(sigil fs))

;; ============================================================

;; TCP echo

@@ -273,6 +274,56 @@

274

(for-each socket-close peers)))))

275

(socket-close server))))

276

+277

;; ============================================================

+278

;; Unix domain sockets

+279

;; ============================================================

+280

+281

(test-group "Unix domain sockets"

+282

(test "unix-listen creates a socket"

+283

(let ((server (unix-listen "/tmp/sigil-test-unix.sock")))

+284

(assert-true (socket? server))

+285

(socket-close server)

+286

(delete-file "/tmp/sigil-test-unix.sock")))

+287

+288

(test "unix-connect to unix-listen socket"

+289

(let ((server (unix-listen "/tmp/sigil-test-unix2.sock")))

+290

(let ((client (unix-connect "/tmp/sigil-test-unix2.sock")))

+291

(assert-true (socket? client))

+292

(socket-close client))

+293

(socket-close server)

+294

(delete-file "/tmp/sigil-test-unix2.sock")))

+295

+296

(test "unix echo via accept"

+297

(let ((server (unix-listen "/tmp/sigil-test-unix3.sock")))

+298

(let* ((client (unix-connect "/tmp/sigil-test-unix3.sock"))

+299

(peer (tcp-accept server)))

+300

(assert-true (socket? peer))

+301

(socket-write-line client "hello unix")

+302

(let ((received (socket-read-line peer)))

+303

(assert-equal "hello unix" received))

+304

(socket-write-line peer "reply")

+305

(let ((reply (socket-read-line client)))

+306

(assert-equal "reply" reply))

+307

(socket-close peer)

+308

(socket-close client))

+309

(socket-close server)

+310

(delete-file "/tmp/sigil-test-unix3.sock")))

+311

+312

(test "unix-listen removes stale socket file"

+313

(let ((path "/tmp/sigil-test-unix4.sock"))

+314

;; Create a socket, close it (leaves stale file)

+315

(let ((s1 (unix-listen path)))

+316

(socket-close s1))

+317

;; Should succeed even though file exists

+318

(let ((s2 (unix-listen path)))

+319

(assert-true (socket? s2))

+320

(socket-close s2)

+321

(delete-file path))))

+322

+323

(test "unix-connect to nonexistent path returns #f"

+324

(let ((result (unix-connect "/tmp/sigil-test-nonexistent.sock")))

+325

(assert-false result))))

+326

327

(test-group "error handling"

328

(test "tcp-connect to closed port returns #f"

329

;; Bind a server to get a port, close it, then try to connect