make cps work with new nimskull again (#332)

Author: alaviss

.github/workflows/ci.yml

@@ -64,10 +64,10 @@ jobs:
 
           - name: nimskull
             version: "*"
-            broken: true
+            broken: false
 
           - name: nimskull
-            version: "<0.1.0-dev.21268"
+            version: "0.1.0-dev.21407"
             broken: false
 
     name: "${{ matrix.os }} (${{ matrix.compiler.name }} ${{ matrix.compiler.version }}${{ matrix.compiler.broken && ', broken' || '' }})"

cps/spec.nim

@@ -5,7 +5,7 @@ boring utilities likely useful to multiple pieces of cps machinery
 ]##
 
 import std/[hashes, sequtils, deques]
-import std/macros except newStmtList, newTree
+import std/macros except newStmtList, newTree, quote, stamp
 
 when (NimMajor, NimMinor) < (1, 5):
   {.fatal: "requires nim-1.5".}
@@ -99,6 +99,14 @@ proc `=destroy`(dest: var ContinuationObj) =
   for key, value in dest.fieldPairs:
     reset value
 
+# quote() shim for nimskull
+when declared(macros.stamp):
+  template quote(body: untyped): NimNode =
+    macros.stamp(body)
+else:
+  template quote(body: untyped): NimNode =
+    macros.quote(body)
+
 template dot*(a, b: NimNode): NimNode =
   ## for constructing foo.bar
   {.line: instantiationInfo().}:

tests/killer.nim

@@ -6,20 +6,32 @@ type
     final: int
     n: int
 
-proc `=destroy`*(k: var Killer) {.raises: [FailError].} =
+proc failMsg(k: Killer): string =
+  case k.n
+  of 0: "uninitialized"
+  of 1: "unused"
+  else: "misused; " & $(k.n - 1) & " uses, expected " & $(k.final - 1)
+
+proc `=destroy`*(k: var Killer) {.raises: [].} =
+  ## Raise a `Defect` if `k` has errors.
+  ##
+  ## `check()` should be used to have errors raised as test failures.
+  ##
+  ## This destructor is a last-ditch effort for when `check()` is not
+  ## run.
+  # Only crash if there's no exception running
+  if k.final != k.n and getCurrentException() == nil:
+    raise newException(Defect, k.failMsg)
+
+proc check*(k: Killer) {.raises: [FailError].} =
+  ## Check `k` for errors.
   if k.final != k.n:
-    let e = getCurrentException()
-    # don't obliterate current exception
-    when defined(ExpectedError):
-      let shouldFail = e.isNil or e isnot FailError or e isnot ExpectedError
-    else:
-      let shouldFail = e.isNil or e isnot FailError
-    if shouldFail:
-      fail:
-        case k.n
-        of 0: "uninitialized"
-        of 1: "unused"
-        else: "misused; " & $(k.n - 1) & " uses, expected " & $(k.final - 1)
+    fail k.failMsg
+
+proc clear*(k: var Killer) =
+  ## Clear and defuse `k`. `k` is not reusable after this.
+  k.final = 0
+  k.n = 0
 
 proc initKiller*(final = 1): Killer =
   Killer(n: 1, final: final + 1)
@@ -31,7 +43,15 @@ proc newKiller*(final = 1): Killer =
 proc inc*(k: var Killer) = system.inc k.n
 template step*(k: Killer): int = k.n - 1
 
-template step*(i: int) {.dirty.} =
+template step*(k: var Killer, i: int) =
+  bind check
+
   check k.n == i, "expected step " & $k.n & " but hit " & $i
   inc k.n
   k.final = max(i, k.final)
+
+template step*(i: int) =
+  mixin k
+  bind step
+
+  step k, i

tests/t10_loops.nim

@@ -182,3 +182,4 @@ suite "loops":
         break
         step 7
     foo()
+    check k

tests/t20_api.nim

@@ -16,6 +16,7 @@ suite "cps api":
     var i = bootstrap()
     check i is int, "bootstrap's output is not an int"
     check i == 3, "bootstrap's output has the wrong value"
+    check k
 
   block:
     ## whelp
@@ -29,6 +30,7 @@ suite "cps api":
     var c = whelp whelped()
     check "whelp's output is bogus":
       c is Cont
+    check k
 
   block:
     ## state symbols and trampoline
@@ -51,6 +53,7 @@ suite "cps api":
       c.state == State.Finished
       c.finished
       not c.running
+    check k
 
   block:
     ## trampolineIt
@@ -69,6 +72,7 @@ suite "cps api":
     check "state post-trampolineIt is " & $c.state:
       not c.dismissed
       c.finished
+    check k
 
   block:
     ## magic voodoo
@@ -99,6 +103,7 @@ suite "cps api":
       return 3
 
     check foo() == 3
+    check k
 
   block:
     ## exporting CPS procedures works
@@ -113,6 +118,7 @@ suite "cps api":
       step 2
 
     foo()
+    check k
 
   block:
     ## one can whelp a cps'd proc that was borrowed
@@ -146,6 +152,7 @@ suite "cps api":
       step 3
 
     foo()
+    check k
 
   block:
     ## calling magic that is not defined for the base type should not compile
@@ -158,25 +165,23 @@ suite "cps api":
 
   block:
     ## calling magic/voodoo with generics continuation parameter works
-    # XXX: Not sure why, but Killer doesn't work here, complaining about
-    #      `k` not in scope.
-    var r = 0
+    var k = newKiller 3
 
     type AnotherCont = ref object of Continuation
     proc magic(c: Cont or AnotherCont): auto {.cpsMagic.} =
-      inc r
+      k.step 3
       c
 
     proc voodoo(c: Cont or AnotherCont) {.cpsVoodoo.} =
-      inc r
+      k.step 2
 
     proc foo() {.cps: Cont.} =
-      inc r
+      step 1
       voodoo()
       magic()
 
     foo()
-    check r == 3
+    check k
 
   block:
     ## magic/voodoo can be defined with `using`
@@ -209,6 +214,7 @@ suite "cps api":
         return 3
 
       check foo() == 3
+      check k
 
   block:
     ## parent-child voodoo works correctly
@@ -245,3 +251,4 @@ suite "cps api":
 
     var a = whelp level_one()
     trampoline a
+    check k

tests/t30_cc.nim

@@ -92,6 +92,7 @@ suite "calling convention":
       step 7
 
     foo: whelp bar
+    check k
 
   block:
     ## whelp helps disambiguate cps callbacks at instantiation
@@ -116,6 +117,7 @@ suite "calling convention":
       check x == 8
 
     foo: whelp(ContCall, bar)
+    check k
 
   block:
     ## run a callback in cps with natural syntax
@@ -140,6 +142,7 @@ suite "calling convention":
         step 3
 
       foo: whelp bar
+      check k
 
   block:
     ## run a callback with no return value in cps
@@ -162,6 +165,7 @@ suite "calling convention":
         step 3
 
       foo: whelp bar
+      check k
 
   block:
     ## callback illustration

tests/t50_hooks.nim

@@ -334,3 +334,4 @@ suite "hooks":
 
     expect IOError:
       foo()
+    check k

tests/t60_returns.nim

@@ -19,6 +19,7 @@ suite "returns and results":
       check x == 8
 
     foo()
+    check k
 
   block:
     ## continuations can return values via bootstrap
@@ -30,6 +31,7 @@ suite "returns and results":
 
     let x = foo(3)
     check x == 9
+    check k
 
   block:
     ## continuations can return values via whelp
@@ -43,6 +45,7 @@ suite "returns and results":
     trampoline c
     check "recover operator works correctly":
       recover(c) == 25
+    check k
 
   block:
     ## assignments to the special result symbol work
@@ -55,6 +58,7 @@ suite "returns and results":
 
       let x = foo(3)
       check x == 9
+      check k
 
     block:
       var k = newKiller 1
@@ -65,6 +69,7 @@ suite "returns and results":
 
       var c = whelp foo(5)
       trampoline c
+      check k
 
   block:
     ## naked returns in continuations with a complication are fine
@@ -77,6 +82,7 @@ suite "returns and results":
       step 2
 
     foo()
+    check k
 
   block:
     ## dismissing a child continuation is fun
@@ -94,6 +100,7 @@ suite "returns and results":
       check x == 8
 
     foo()
+    check k
 
   block:
     ## assignment to a continuation return value
@@ -111,6 +118,7 @@ suite "returns and results":
       check x == 8
 
     foo()
+    check k
 
   block:
     ## local assignment tuple unpacking a continution return value
@@ -132,6 +140,7 @@ suite "returns and results":
     trampoline c
     check "recover operator works correctly":
       6 == recover c
+    check k
 
   block:
     ## discarding a continuation return value works
@@ -145,6 +154,7 @@ suite "returns and results":
       step 2
 
     foo()
+    check k
 
   block:
     ## returning a continuation return value works
@@ -157,6 +167,7 @@ suite "returns and results":
       return bar()
 
     check foo() == "test"
+    check k
 
   block:
     ## returning an anonymous tuple declaration type
@@ -173,6 +184,7 @@ suite "returns and results":
       check (x, y) == (10, 20)
 
     foo()
+    check k
 
   block:
     ## returning a named tuple type
@@ -192,6 +204,7 @@ suite "returns and results":
       check (x, y) == (10, 20)
 
     foo()
+    check k
 
   block:
     ## converting a cps return value
@@ -220,6 +233,7 @@ suite "returns and results":
       step 3
 
     foo()
+    check k
 
   block:
     ## calling continuation with variant object access as parameter

tests/t70_locals.nim

@@ -403,7 +403,8 @@ suite "tuples":
     check r == 2
 
 type
-  K = distinct object
+  KObj = object
+  K = distinct KObj
 
 var k = initKiller 9
 
@@ -463,6 +464,7 @@ suite "lifetimes":
         # destroy bar.m; eg. step == 11
 
       foo()
+      check k
 
   block:
     ## lifetime canary for distinct objects
@@ -501,6 +503,7 @@ suite "lifetimes":
       # destroy bar.m; eg. step == 9
 
     foo()
+    check k
 
 import std/sugar