wip

cps.nim

@@ -1,7 +1,7 @@
 import std/[genasts, deques]
 import cps/[spec, transform, rewrites, hooks, exprs, normalizedast]
 import std/macros except newStmtList, newTree
-export Continuation, ContinuationProc, State
+export Continuation, ContinuationProc, State, Whelp
 export cpsCall, cpsMagicCall, cpsVoodooCall, cpsMustJump
 export cpsMagic, cpsVoodoo, trampoline, trampolineIt
 export writeStackFrames, writeTraceDeque
@@ -63,6 +63,12 @@ macro cps*(T: typed, n: typed): untyped =
           # Add the flattening phase which will be run first
           newCall(bindSym"cpsFlattenExpr"):
             n
+    of nnkProcTy:
+      # converting a cps callback
+      result = cpsCallbackTypeDef(T, n)
+      result = workaroundRewrites result.NormNode
+      echo treeRepr(result)
+      echo repr(result)
     else:
       result = getAst(cpsTransform(T, n))
 

cps/spec.nim

@@ -54,6 +54,10 @@ type
 
   ContinuationProc*[T] = proc(c: T): T {.nimcall.}
 
+  Whelp*[C: Continuation; R; P: proc] = object
+    fn: P                 ## a pointer to a specific `whelp` function
+    rs: proc (cont: C): R ## the type signature of the `()` functions
+
   TraceFrame* = object ## a record of where the continuation has been
     hook*: Hook        ## the hook that provoked the trace entry
     fun*: string       ## a short label for the notable symbol

cps/transform.nim

@@ -1102,6 +1102,16 @@ macro cpsHandleUnhandledException(contType: typed; n: typed): untyped =
   debugAnnotation cpsHandleUnhandledException, n:
     it = it.filter(handle)
 
+proc cpsCallbackTypeDef*(T: NimNode, n: NimNode): NimNode =
+  ## looks like cpsTransformProc but applies to proc typedefs;
+  ## this is where we create our calling convention concept
+  let params = copyNimTree n[0]
+  let R = copyNimTree params[0]
+  params[0] = T
+  let P = nnkProcTy.newTree(params, newEmptyNode())
+  result = nnkBracketExpr.newTree(bindSym"Whelp", T, R, P)
+  result = workaroundRewrites result.NormNode
+
 proc cpsTransformProc(T: NimNode, n: NimNode): NormNode =
   ## rewrite the target procedure in Continuation-Passing Style