idetools improvements; preparation of first class iterators; fixes #183

compiler/ccgstmts.nim

@@ -92,6 +92,25 @@ template preserveBreakIdx(body: stmt): stmt =
   body
   p.breakIdx = oldBreakIdx
 
+proc genState(p: BProc, n: PNode) =
+  internalAssert n.len == 2 and n.sons[0].kind == nkIntLit
+  let idx = n.sons[0].intVal
+  lineCg(p, cpsStmts, "STATE$1: ;$n", [idx.toRope])
+  genStmts(p, n.sons[1])
+
+proc genGotoState(p: BProc, n: PNode) =
+  # we resist the temptation to translate it into duff's device as it later
+  # will be translated into computed gotos anyway for GCC at least:
+  # switch (x.state) {
+  #   case 0: goto STATE0;
+  # ...
+  var a: TLoc
+  initLocExpr(p, n.sons[0], a)
+  lineF(p, cpsStmts, "switch ($1) {$n", [rdLoc(a)])
+  for i in 0 .. lastOrd(n.sons[0].typ):
+    lineF(p, cpsStmts, "case $1: goto STATE$1;$n", [toRope(i)])
+  lineF(p, cpsStmts, "}$n", [])
+
 proc genSingleVar(p: BProc, a: PNode) =
   var v = a.sons[0].sym
   if sfCompileTime in v.flags: return
@@ -863,5 +882,7 @@ proc genStmts(p: BProc, t: PNode) =
         if prc.getBody.kind != nkEmpty or lfDynamicLib in prc.loc.flags: 
           genProc(p.module, prc)
   of nkParForStmt: genParForStmt(p, t)
+  of nkState: genState(p, t)
+  of nkGotoState: genGotoState(p, t)
   else: internalError(t.info, "genStmts(" & $t.kind & ')')