From a4ad640df16f3018682965ffbd83ecff7a6e460c Mon Sep 17 00:00:00 2001
From: Andy Davidoff <andy+github@disruptek.com>
Date: Thu, 23 Jul 2020 21:18:06 -0400
Subject: [PATCH] 0.0.5: signals, wait, semaphores

---
 README.md                 |  4 ++--
 cps.nimble                |  3 ++-
 cps/eventqueue.nim        | 27 +++++++++++++++++++++++----
 cps/semaphore.nim         |  2 ++
 docs/cps.html             |  2 +-
 docs/cps/environment.html |  2 +-
 docs/theindex.html        |  2 +-
 tests/tsignal.nim         | 18 ++++++++++++++++++
 tests/tsignal.nim.cfg     |  5 +++++
 9 files changed, 55 insertions(+), 10 deletions(-)
 create mode 100644 tests/tsignal.nim
 create mode 100644 tests/tsignal.nim.cfg

diff --git a/README.md b/README.md
index 99df8f32..ca2a9630 100644
--- a/README.md
+++ b/README.md
@@ -36,8 +36,8 @@ Key primitives and their implementation status, in order of priority:
 - [x] sleep
 - [x] yield
 - [x] discard
-- [ ] signal
-- [ ] wait
+- [x] signal
+- [x] wait
 - [ ] I/O
 - [ ] fork
 - [ ] thread
diff --git a/cps.nimble b/cps.nimble
index 4d39ad3d..be7e94e5 100644
--- a/cps.nimble
+++ b/cps.nimble
@@ -1,4 +1,4 @@
-version = "0.0.4"
+version = "0.0.5"
 author = "disruptek"
 description = "continuation-passing style"
 license = "MIT"
@@ -25,3 +25,4 @@ task test, "run tests for travis":
   execTest("tests/test.nim")
   execTest("tests/tock.nim")
   execTest("tests/tyield.nim")
+  execTest("tests/tsignal.nim")
diff --git a/cps/eventqueue.nim b/cps/eventqueue.nim
index b4088cf7..cf698525 100644
--- a/cps/eventqueue.nim
+++ b/cps/eventqueue.nim
@@ -144,6 +144,14 @@ proc len*(eq: EventQueue): int =
   ## The number of pending continuations.
   result = len(eq.goto) + len(eq.yields) + len(eq.pending)
 
+proc `[]=`(eq: var EventQueue; s: var Semaphore; id: Id) =
+  ## put a semaphore into the queue with its registration
+  assert id != invalidId
+  assert id != wakeupId
+  assert not s.isReady
+  assert s.id.Id != invalidId
+  eq.pending[s] = id
+
 proc `[]=`(eq: var EventQueue; id: Id; cont: Cont) =
   ## put a continuation into the queue according to its registration
   assert id != invalidId
@@ -320,9 +328,9 @@ template signalImpl(s: Semaphore; body: untyped): untyped =
       wakeUp()
 
 proc cpsSignal*(s: var Semaphore): Cont {.cpsMagic.} =
-  ## signal the given semaphore, causing the first waiting continuation
+  ## Signal the given semaphore, causing the first waiting continuation
   ## to be queued for execution in the dispatcher; control remains in
-  ## the calling procedure
+  ## the calling procedure.
   result = c
   signal s
   withReady s:
@@ -331,9 +339,9 @@ proc cpsSignal*(s: var Semaphore): Cont {.cpsMagic.} =
       discard
 
 proc cpsSignalAll*(s: var Semaphore): Cont {.cpsMagic.} =
-  ## signal the given semaphore, causing all waiting continuations
+  ## Signal the given semaphore, causing all waiting continuations
   ## to be queued for execution in the dispatcher; control remains in
-  ## the calling procedure
+  ## the calling procedure.
   result = c
   signal s
   if s.isReady:
@@ -341,3 +349,14 @@ proc cpsSignalAll*(s: var Semaphore): Cont {.cpsMagic.} =
     while true:
       signalImpl s:
         break
+
+proc cpsWait*(s: var Semaphore): Cont {.cpsMagic.} =
+  ## Queue the current continuation pending readiness of the given
+  ## Semaphore `s`.
+  let id = nextId()
+  if s.isReady:
+    addLast(eq.yields, c)
+    wakeUp()
+  else:
+    eq[s] = id
+    eq[id] = c
diff --git a/cps/semaphore.nim b/cps/semaphore.nim
index 1a904d76..25be2e7c 100644
--- a/cps/semaphore.nim
+++ b/cps/semaphore.nim
@@ -8,6 +8,8 @@ type
     cond: Cond
     count: int
 
+proc id*(s: Semaphore): int = s.id
+
 proc hash*(s: Semaphore): Hash =
   result = s.id.Hash
 
diff --git a/docs/cps.html b/docs/cps.html
index a69c9e25..492c5e78 100644
--- a/docs/cps.html
+++ b/docs/cps.html
@@ -147,7 +147,7 @@ <h1><a class="toc-backref" href="#17">Macros</a></h1>
       <div class="twelve-columns footer">
         <span class="nim-sprite"></span>
         <br/>
-        <small style="color: var(--hint);">Made with Nim. Generated: 2020-07-24 00:54:59 UTC</small>
+        <small style="color: var(--hint);">Made with Nim. Generated: 2020-07-24 01:17:04 UTC</small>
       </div>
     </div>
   </div>
diff --git a/docs/cps/environment.html b/docs/cps/environment.html
index aa3c2852..69a29d58 100644
--- a/docs/cps/environment.html
+++ b/docs/cps/environment.html
@@ -446,7 +446,7 @@ <h1><a class="toc-backref" href="#18">Templates</a></h1>
       <div class="twelve-columns footer">
         <span class="nim-sprite"></span>
         <br/>
-        <small style="color: var(--hint);">Made with Nim. Generated: 2020-07-24 00:54:59 UTC</small>
+        <small style="color: var(--hint);">Made with Nim. Generated: 2020-07-24 01:17:04 UTC</small>
       </div>
     </div>
   </div>
diff --git a/docs/theindex.html b/docs/theindex.html
index 9e7e602c..4f08f443 100644
--- a/docs/theindex.html
+++ b/docs/theindex.html
@@ -223,7 +223,7 @@ <h1 class="title">Index</h1>
       <div class="twelve-columns footer">
         <span class="nim-sprite"></span>
         <br/>
-        <small style="color: var(--hint);">Made with Nim. Generated: 2020-07-24 00:54:59 UTC</small>
+        <small style="color: var(--hint);">Made with Nim. Generated: 2020-07-24 01:17:04 UTC</small>
       </div>
     </div>
   </div>
diff --git a/tests/tsignal.nim b/tests/tsignal.nim
new file mode 100644
index 00000000..052760ca
--- /dev/null
+++ b/tests/tsignal.nim
@@ -0,0 +1,18 @@
+import cps
+import cps/eventqueue
+
+var sem = newSemaphore()
+var success = false
+
+proc tick(ms: int): Cont {.cps.} =
+  cpsSleep ms
+  cpsSignal(sem)
+
+proc tock(): Cont {.cps.} =
+  cpsWait sem
+  success = true
+
+trampoline tick(10)
+trampoline tock()
+
+run()
diff --git a/tests/tsignal.nim.cfg b/tests/tsignal.nim.cfg
new file mode 100644
index 00000000..f9f78b32
--- /dev/null
+++ b/tests/tsignal.nim.cfg
@@ -0,0 +1,5 @@
+--path="$config/.."
+--threads:on
+--define:threadsafe
+--gc:arc
+--define:cpsDebug