feat(http): Http.* poll-based HTTP/HTTPS client over a native NSURLConnection backend (#6)

Adds the Http.* namespace and its transport, the HTTP client from #6. The JSON
companion the proposal called for already shipped as Json.* (#44).

- runtime/native/http.ll: the macOS transport — NSURLConnection driven through
  the objc runtime C ABI (no ObjC/C source), run on a detached pthread so the
  frame never blocks; TLS is the system's, on by default. A fixed slot pool holds
  each in-flight request; the worker publishes status/body/response behind an
  atomic done flag (release/acquire). Spliced + Foundation linked only when a
  program uses Http.*.
- runtime/native/http.ludic: the Http.* runtime — get/post/request, the
  open/set/body/send builder, poll/status/ok/text/body_len/header/free, plus a
  pure-Ludic response parser (Http.parse + case-insensitive header lookup) that
  is transport-independent and portable.
- compiler: Http.* dispatch, g_uses_http splice, hs_* transport intrinsics +
  declarations, the conditional Foundation link, and a new \r string/char escape
  the protocol needs.
- docs: a full docs/language/http section (16 pages); check-impl/check-docs green.
- test: examples/library/http.ludic self-asserts the parser offline (Darwin-gated
  build via the canonical path, since it links Foundation).

Verified end to end against real endpoints: HTTPS GET (200 + headers + body) and
POST (body + custom header). HTTP is out-of-band and never feeds the
deterministic sim. Reseeded; suites green (81 + 29).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

selfhost/backend/emit_call.ludic

@@ -231,6 +231,27 @@ function emit_ns_call(ns: pointer, meth: pointer, e: Node) -> Val {
     if (meth == "pitch")      { bare = "audio_pitch";      push(labels, "v") }
     if (meth == "is_playing") { bare = "audio_is_playing"; push(labels, "id") }
   }
+  # Http.* (#6) — a poll-based HTTP/HTTPS client (runtime/native/http.ludic +
+  # http.ll). Out-of-band, never part of the deterministic sim. Pairs with Json.*
+  # (#44) for (de)serialization: Json.parse(Http.text(h)).
+  if (ns == "Http") {
+    if (meth == "get")       { bare = "http_get";        push(labels, "url") }
+    if (meth == "post")      { bare = "http_post";       push(labels, "url"); push(labels, "body") }
+    if (meth == "request")   { bare = "http_request";    push(labels, "method"); push(labels, "url"); push(labels, "body") }
+    if (meth == "open")      { bare = "http_open";        push(labels, "method"); push(labels, "url") }
+    if (meth == "set")       { bare = "http_set_header";  push(labels, "handle"); push(labels, "name"); push(labels, "value") }
+    if (meth == "body")      { bare = "http_body";        push(labels, "handle"); push(labels, "body") }
+    if (meth == "body_bytes"){ bare = "http_body_n";      push(labels, "handle"); push(labels, "bytes"); push(labels, "len") }
+    if (meth == "send")      { bare = "http_send_req";    push(labels, "handle") }
+    if (meth == "poll")      { bare = "http_poll";        push(labels, "handle") }
+    if (meth == "status")    { bare = "http_status_of";   push(labels, "handle") }
+    if (meth == "ok")        { bare = "http_ok";          push(labels, "handle") }
+    if (meth == "text")      { bare = "http_text";        push(labels, "handle") }
+    if (meth == "body_len")  { bare = "http_body_len";    push(labels, "handle") }
+    if (meth == "header")    { bare = "http_header_of";   push(labels, "handle"); push(labels, "name") }
+    if (meth == "free")      { bare = "http_close";       push(labels, "handle") }
+    if (meth == "parse")     { bare = "http_parse";       push(labels, "bytes"); push(labels, "len") }
+  }
   # Phase 3: the bare reflection / networking / process builtins, namespaced.
   # Each is a pure alias — the callee is rewritten to the bare name below.
   if (ns == "World") {

selfhost/backend/emit_head.ludic

@@ -73,6 +73,16 @@ function emit_header() -> void {
   emith("declare i32 @snd_playing(ptr)\n")
   emith("declare void @snd_set_volume(ptr, i32)\n")
   emith("declare void @snd_set_rate(ptr, i32)\n")
+  emith("declare ptr @hs_req_new(ptr, ptr)\n")          # #6 HTTP transport (http.ll)
+  emith("declare void @hs_req_header(ptr, ptr, ptr)\n")
+  emith("declare void @hs_req_body(ptr, ptr, i32)\n")
+  emith("declare void @hs_send(i32, ptr)\n")
+  emith("declare i32 @hs_done(i32)\n")
+  emith("declare i32 @hs_status(i32)\n")
+  emith("declare ptr @hs_body(i32)\n")
+  emith("declare i32 @hs_blen(i32)\n")
+  emith("declare ptr @hs_header(i32, ptr)\n")
+  emith("declare void @hs_free(i32)\n")
   emith("@__stderrp = external global ptr\n")
   emith("@__stdoutp = external global ptr\n")
   emith("@.fmt_int = private unnamed_addr constant [4 x i8] c\"%d\\0A\\00\"\n")

selfhost/backend/emit_intrin2.ludic

@@ -15,6 +15,9 @@ function is_intrinsic2(name: pointer) -> bool {
   if (name == "win_pad") or (name == "win_touch") { return true }    # #51 gamepad / touch
   if (name == "snd_load") or (name == "snd_play") or (name == "snd_stop") { return true }   # #22 audio
   if (name == "snd_playing") or (name == "snd_set_volume") or (name == "snd_set_rate") { return true }
+  if (name == "hs_req_new") or (name == "hs_req_header") or (name == "hs_req_body") { return true }   # #6 HTTP
+  if (name == "hs_send") or (name == "hs_done") or (name == "hs_status") or (name == "hs_body") { return true }
+  if (name == "hs_blen") or (name == "hs_header") or (name == "hs_free") { return true }
   return false
 }
 
@@ -72,5 +75,16 @@ function emit_intrinsic2(name: pointer, e: Node) -> Val {
   if (name == "snd_playing") { let a = arg_code(e, 0);  return val(emit_bind(`call i32 @snd_playing(ptr {a})`), "int") }
   if (name == "snd_set_volume") { let a = arg_code(e, 0);  let b = arg_code(e, 1);  emit("  call void @snd_set_volume(ptr ");  emit(a);  emit(", i32 ");  emit(b);  emit(")\n");  return val("0", "void") }
   if (name == "snd_set_rate") { let a = arg_code(e, 0);  let b = arg_code(e, 1);  emit("  call void @snd_set_rate(ptr ");  emit(a);  emit(", i32 ");  emit(b);  emit(")\n");  return val("0", "void") }
+  # #6 HTTP transport — NSURLConnection on a background thread (http.ll).
+  if (name == "hs_req_new") { let a = arg_code(e, 0);  let b = arg_code(e, 1);  return val(emit_bind(`call ptr @hs_req_new(ptr {a}, ptr {b})`), "pointer") }
+  if (name == "hs_req_header") { let a = arg_code(e, 0);  let b = arg_code(e, 1);  let c = arg_code(e, 2);  emit("  call void @hs_req_header(ptr ");  emit(a);  emit(", ptr ");  emit(b);  emit(", ptr ");  emit(c);  emit(")\n");  return val("0", "void") }
+  if (name == "hs_req_body") { let a = arg_code(e, 0);  let b = arg_code(e, 1);  let c = arg_code(e, 2);  emit("  call void @hs_req_body(ptr ");  emit(a);  emit(", ptr ");  emit(b);  emit(", i32 ");  emit(c);  emit(")\n");  return val("0", "void") }
+  if (name == "hs_send") { let a = arg_code(e, 0);  let b = arg_code(e, 1);  emit("  call void @hs_send(i32 ");  emit(a);  emit(", ptr ");  emit(b);  emit(")\n");  return val("0", "void") }
+  if (name == "hs_done") { let a = arg_code(e, 0);  return val(emit_bind(`call i32 @hs_done(i32 {a})`), "int") }
+  if (name == "hs_status") { let a = arg_code(e, 0);  return val(emit_bind(`call i32 @hs_status(i32 {a})`), "int") }
+  if (name == "hs_body") { let a = arg_code(e, 0);  return val(emit_bind(`call ptr @hs_body(i32 {a})`), "pointer") }
+  if (name == "hs_blen") { let a = arg_code(e, 0);  return val(emit_bind(`call i32 @hs_blen(i32 {a})`), "int") }
+  if (name == "hs_header") { let a = arg_code(e, 0);  let b = arg_code(e, 1);  return val(emit_bind(`call ptr @hs_header(i32 {a}, ptr {b})`), "pointer") }
+  if (name == "hs_free") { let a = arg_code(e, 0);  emit("  call void @hs_free(i32 ");  emit(a);  emit(")\n");  return val("0", "void") }
   return val("0", "void")
 }

selfhost/frontend/lex.ludic

@@ -60,6 +60,7 @@ function lex(src: pointer) -> void {
           let e = src[i + 1]
           var r = e
           if e == 110 { r = 10 }
+          if e == 114 { r = 13 }
           if e == 116 { r = 9 }
           if e == 48  { r = 0 }
           out[j] = r;  j = j + 1;  i = i + 2
@@ -86,6 +87,7 @@ function lex(src: pointer) -> void {
       if src[i] == 92 {
         let e = src[i + 1]
         if e == 110 { v = 10 }
+        if e == 114 { v = 13 }
         if e == 116 { v = 9 }
         if e == 48  { v = 0 }
         i = i + 2

selfhost/frontend/parse.ludic

@@ -194,6 +194,8 @@ function p_postfix() -> Node {
       if e.a.kind == E_ID and e.a.s == "Motion" and e.s == "to" { g_uses_anim_rt = true }
       # Audio.* (#22) — any Audio method splices the audio runtime.
       if e.a.kind == E_ID and e.a.s == "Audio" { g_uses_audio = true }
+      # Http.* (#6) — any Http method splices the HTTP client runtime.
+      if e.a.kind == E_ID and e.a.s == "Http" { g_uses_http = true }
       # Tween.to/chain/delay/value/stop/parallel (#48): the fluent stateful handles
       # live in tween.ludic, advanced by an engine-owned system each Update tick.
       if e.a.kind == E_ID and e.a.s == "Tween" and (e.s == "to" or e.s == "chain" or e.s == "delay" or e.s == "value" or e.s == "stop" or e.s == "parallel") { g_uses_tween_rt = true }
@@ -429,6 +431,7 @@ var g_uses_input: bool = false    # a program used Input.bind/down/poll/… (act
 var g_uses_anim_rt: bool = false  # Anim.play/clip/on_frame/fired or Motion.to (#48) -> splice systems.ludic + force the reflection ABI
 var g_uses_tween_rt: bool = false # Tween.to/chain/delay/… (#48) -> splice tween.ludic + run esys_tween each Update
 var g_uses_audio: bool = false    # Audio.* (#22) -> splice audio.ludic; a windowed build also links audio.ll + AVFoundation
+var g_uses_http:  bool = false    # Http.* (#6) -> splice http.ludic; links http.ll + Foundation (macOS)
 
 function already_loaded(full: pointer) -> bool {
   var i = 0
@@ -657,6 +660,14 @@ function maybe_splice_runtime() -> void {
     do_import("runtime/native/audio.ludic")
     cur_dir = saved
   }
+  # Http.* (#6): splice the HTTP client. The transport (hs_* intrinsics) is native
+  # (linked from http.ll), but the response parser is pure Ludic; self-contained,
+  # so it works in a plain program too.
+  if g_uses_http {
+    cur_dir = ""
+    do_import("runtime/native/http.ludic")
+    cur_dir = saved
+  }
   # Anim.play/Motion.to sugar (#48): the writes live in systems.ludic and use the
   # reflection ABI, so splice it and force the world table even when the game does
   # not otherwise trip uses_engine_systems.

selfhost/main.ludic

@@ -173,6 +173,13 @@ entry {
       cmd = `{cmd} {audio} -Wl,-needed_framework,AVFoundation`
     }
   }
+  # Http.* (#6) links the native transport and Foundation (NSURLConnection etc.,
+  # reached by name). Works headless too, so it is outside the windowed block —
+  # macOS-only for now, which is where the toolchain runs.
+  if g_uses_http {
+    let http = path_join(home, "runtime/native/http.ll")
+    cmd = `{cmd} {http} -Wl,-needed_framework,Foundation`
+  }
   cmd = `{cmd} -o {out}`
 
   let rc = run(cmd)