Merge branch 'master' of github.com:Araq/Nimrod

15 files changed, 421 insertions, 239 deletions

diff --git a/compiler/ast.nim b/compiler/ast.nim
index c6a2b32e7..10a3d8039 100755
--- a/compiler/ast.nim
+++ b/compiler/ast.nim
@@ -244,12 +244,17 @@ const
   sfDispatcher* = sfDeadCodeElim # copied method symbol is the dispatcher
   sfNoInit* = sfMainModule       # don't generate code to init the variable
 
-  sfImmediate* = sfDeadCodeElim  # macro or template is immediately expanded
-                                 # without considering any possible overloads
+  sfImmediate* = sfDeadCodeElim
+    # macro or template is immediately expanded
+    # without considering any possible overloads
   
-  sfAnon* = sfCompilerProc  # symbol name that was generated by the compiler
-                            # the compiler will avoid printing such names 
-                            # in user messages.
+  sfAnon* = sfDiscardable
+    # symbol name that was generated by the compiler
+    # the compiler will avoid printing such names 
+    # in user messages.
+  
+  sfShadowed* = sfInnerProc
+    # a variable that was shadowed in some inner scope
 
 const
   # getting ready for the future expr/stmt merge
@@ -647,6 +652,14 @@ const
   resultPos* = 5
   dispatcherPos* = 6 # caution: if method has no 'result' it can be position 5!
 
+  nkCallKinds* = {nkCall, nkInfix, nkPrefix, nkPostfix,
+                  nkCommand, nkCallStrLit}
+
+  nkLambdaKinds* = {nkLambda, nkDo}
+
+  skLocalVars* = {skVar, skLet, skForVar, skParam}
+
+
 # creator procs:
 proc NewSym*(symKind: TSymKind, Name: PIdent, owner: PSym): PSym
 proc NewType*(kind: TTypeKind, owner: PSym): PType
@@ -691,11 +704,6 @@ proc copyNode*(src: PNode): PNode
 proc copyTree*(src: PNode): PNode
   # does copy its sons!
 
-const nkCallKinds* = {nkCall, nkInfix, nkPrefix, nkPostfix, nkCommand,
-                      nkCallStrLit}
-
-const nkLambdaKinds* = {nkLambda, nkDo}
-
 proc isCallExpr*(n: PNode): bool =
   result = n.kind in nkCallKinds
 
diff --git a/compiler/ccgcalls.nim b/compiler/ccgcalls.nim
index cb6014626..f2fa6a280 100644
--- a/compiler/ccgcalls.nim
+++ b/compiler/ccgcalls.nim
@@ -6,6 +6,8 @@
 #    See the file "copying.txt", included in this
 #    distribution, for details about the copyright.
 #
+#
+# included from cgen.nim
 
 proc leftAppearsOnRightSide(le, ri: PNode): bool =
   if le != nil:
@@ -16,9 +18,6 @@ proc leftAppearsOnRightSide(le, ri: PNode): bool =
 proc hasNoInit(call: PNode): bool {.inline.} =
   result = call.sons[0].kind == nkSym and sfNoInit in call.sons[0].sym.flags
 
-proc resetLoc(p: BProc, d: var TLoc) =
-  zeroVar(p, d, containsGarbageCollectedRef(d.t))
-
 proc fixupCall(p: BProc, le, ri: PNode, d: var TLoc, pl: PRope) =
   var pl = pl
   var typ = ri.sons[0].typ # getUniqueType() is too expensive here!
@@ -34,15 +33,15 @@ proc fixupCall(p: BProc, le, ri: PNode, d: var TLoc, pl: PRope) =
           resetLoc(p, d)
         app(pl, addrLoc(d))
         app(pl, ")")
-        app(p.s[cpsStmts], pl)
-        appf(p.s[cpsStmts], ";$n")
+        app(p.s(cpsStmts), pl)
+        appf(p.s(cpsStmts), ";$n")
       else:
         var tmp: TLoc
         getTemp(p, typ.sons[0], tmp)
         app(pl, addrLoc(tmp))
         app(pl, ")")
-        app(p.s[cpsStmts], pl)
-        appf(p.s[cpsStmts], ";$n")
+        app(p.s(cpsStmts), pl)
+        appf(p.s(cpsStmts), ";$n")
         genAssignment(p, d, tmp, {}) # no need for deep copying
     else:
       app(pl, ")")
@@ -54,8 +53,8 @@ proc fixupCall(p: BProc, le, ri: PNode, d: var TLoc, pl: PRope) =
       genAssignment(p, d, list, {}) # no need for deep copying
   else:
     app(pl, ")")
-    app(p.s[cpsStmts], pl)
-    appf(p.s[cpsStmts], ";$n")
+    app(p.s(cpsStmts), pl)
+    appf(p.s(cpsStmts), ";$n")
 
 proc isInCurrentFrame(p: BProc, n: PNode): bool =
   # checks if `n` is an expression that refers to the current frame;
@@ -164,7 +163,7 @@ proc genClosureCall(p: BProc, le, ri: PNode, d: var TLoc) =
     if i < length - 1: app(pl, ", ")
   
   template genCallPattern =
-    appf(p.s[cpsStmts], CallPattern, op.r, pl, pl.addComma, rawProc)
+    appf(p.s(cpsStmts), CallPattern, op.r, pl, pl.addComma, rawProc)
 
   let rawProc = getRawProcType(p, typ)
   if typ.sons[0] != nil:
@@ -179,13 +178,13 @@ proc genClosureCall(p: BProc, le, ri: PNode, d: var TLoc) =
           resetLoc(p, d)
         app(pl, addrLoc(d))
         genCallPattern()
-        appf(p.s[cpsStmts], ";$n")
+        appf(p.s(cpsStmts), ";$n")
       else:
         var tmp: TLoc
         getTemp(p, typ.sons[0], tmp)
         app(pl, addrLoc(tmp))        
         genCallPattern()
-        appf(p.s[cpsStmts], ";$n")
+        appf(p.s(cpsStmts), ";$n")
         genAssignment(p, d, tmp, {}) # no need for deep copying
     else:
       if d.k == locNone: getTemp(p, typ.sons[0], d)
@@ -196,7 +195,7 @@ proc genClosureCall(p: BProc, le, ri: PNode, d: var TLoc) =
       genAssignment(p, d, list, {}) # no need for deep copying
   else:
     genCallPattern()
-    appf(p.s[cpsStmts], ";$n")
+    appf(p.s(cpsStmts), ";$n")
   
 proc genInfixCall(p: BProc, le, ri: PNode, d: var TLoc) =
   var op, a: TLoc
@@ -261,15 +260,15 @@ proc genNamedParamCall(p: BProc, ri: PNode, d: var TLoc) =
         app(pl, "Result: ")
         app(pl, addrLoc(d))
         app(pl, "]")
-        app(p.s[cpsStmts], pl)
-        appf(p.s[cpsStmts], ";$n")
+        app(p.s(cpsStmts), pl)
+        appf(p.s(cpsStmts), ";$n")
       else:
         var tmp: TLoc
         getTemp(p, typ.sons[0], tmp)
         app(pl, addrLoc(tmp))
         app(pl, "]")
-        app(p.s[cpsStmts], pl)
-        appf(p.s[cpsStmts], ";$n")
+        app(p.s(cpsStmts), pl)
+        appf(p.s(cpsStmts), ";$n")
         genAssignment(p, d, tmp, {}) # no need for deep copying
     else:
       app(pl, "]")
@@ -281,8 +280,8 @@ proc genNamedParamCall(p: BProc, ri: PNode, d: var TLoc) =
       genAssignment(p, d, list, {}) # no need for deep copying
   else:
     app(pl, "]")
-    app(p.s[cpsStmts], pl)
-    appf(p.s[cpsStmts], ";$n")
+    app(p.s(cpsStmts), pl)
+    appf(p.s(cpsStmts), ";$n")
 
 proc genCall(p: BProc, e: PNode, d: var TLoc) =
   if e.sons[0].typ.callConv == ccClosure:
diff --git a/compiler/ccgexprs.nim b/compiler/ccgexprs.nim
index d03142208..34418f353 100755
--- a/compiler/ccgexprs.nim
+++ b/compiler/ccgexprs.nim
@@ -160,7 +160,7 @@ proc getStorageLoc(n: PNode): TStorageLoc =
 
 proc genRefAssign(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
   if dest.s == OnStack or optRefcGC notin gGlobalOptions:
-    appf(p.s[cpsStmts], "$1 = $2;$n", [rdLoc(dest), rdLoc(src)])
+    appf(p.s(cpsStmts), "$1 = $2;$n", [rdLoc(dest), rdLoc(src)])
     if needToKeepAlive in flags: keepAlive(p, dest)
   elif dest.s == OnHeap:
     # location is on heap
@@ -180,13 +180,13 @@ proc genRefAssign(p: BProc, dest, src: TLoc, flags: TAssignmentFlags) =
     #      appf(p.s[cpsStmts], 'if ($1) nimGCunref($1);$n', [rdLoc(dest)])
     #    appf(p.s[cpsStmts], '$1 = $2;$n', [rdLoc(dest), rdLoc(src)])
     if canFormAcycle(dest.t):
-      appcg(p.module, p.s[cpsStmts], "#asgnRef((void**) $1, $2);$n",
+      appcg(p.module, p.s(cpsStmts), "#asgnRef((void**) $1, $2);$n",
            [addrLoc(dest), rdLoc(src)])
     else:
-      appcg(p.module, p.s[cpsStmts], "#asgnRefNoCycle((void**) $1, $2);$n",
+      appcg(p.module, p.s(cpsStmts), "#asgnRefNoCycle((void**) $1, $2);$n",
            [addrLoc(dest), rdLoc(src)])
   else:
-    appcg(p.module, p.s[cpsStmts], "#unsureAsgnRef((void**) $1, $2);$n",
+    appcg(p.module, p.s(cpsStmts), "#unsureAsgnRef((void**) $1, $2);$n",
          [addrLoc(dest), rdLoc(src)])
     if needToKeepAlive in flags: keepAlive(p, dest)
 
@@ -736,9 +736,9 @@ proc genAndOr(p: BProc, e: PNode, d: var TLoc, m: TMagic) =
   expr(p, e.sons[1], tmp)
   L = getLabel(p)
   if m == mOr:
-    appf(p.s[cpsStmts], "if ($1) goto $2;$n", [rdLoc(tmp), L])
+    appf(p.s(cpsStmts), "if ($1) goto $2;$n", [rdLoc(tmp), L])
   else:
-    appf(p.s[cpsStmts], "if (!($1)) goto $2;$n", [rdLoc(tmp), L])
+    appf(p.s(cpsStmts), "if (!($1)) goto $2;$n", [rdLoc(tmp), L])
   expr(p, e.sons[2], tmp)
   fixLabel(p, L)
   if d.k == locNone:
@@ -771,9 +771,9 @@ proc genIfExpr(p: BProc, n: PNode, d: var TLoc) =
     of nkElifExpr:
       initLocExpr(p, it.sons[0], a)
       Lelse = getLabel(p)
-      appf(p.s[cpsStmts], "if (!$1) goto $2;$n", [rdLoc(a), Lelse])
+      appf(p.s(cpsStmts), "if (!$1) goto $2;$n", [rdLoc(a), Lelse])
       expr(p, it.sons[1], tmp)
-      appf(p.s[cpsStmts], "goto $1;$n", [Lend])
+      appf(p.s(cpsStmts), "goto $1;$n", [Lend])
       fixLabel(p, Lelse)
     of nkElseExpr:
       expr(p, it.sons[0], tmp)
@@ -832,7 +832,7 @@ proc genStrConcat(p: BProc, e: PNode, d: var TLoc) =
         appf(lens, "$1->$2 + ", [rdLoc(a), lenField()])
       appcg(p.module, appends, "#appendString($1, $2);$n", [tmp.r, rdLoc(a)])
   appcg(p, cpsStmts, "$1 = #rawNewString($2$3);$n", [tmp.r, lens, toRope(L)])
-  app(p.s[cpsStmts], appends)
+  app(p.s(cpsStmts), appends)
   if d.k == locNone:
     d = tmp
     keepAlive(p, tmp)
@@ -874,7 +874,7 @@ proc genStrAppend(p: BProc, e: PNode, d: var TLoc) =
   appcg(p, cpsStmts, "$1 = #resizeString($1, $2$3);$n",
        [rdLoc(dest), lens, toRope(L)])
   keepAlive(p, dest)
-  app(p.s[cpsStmts], appends)
+  app(p.s(cpsStmts), appends)
 
 proc genSeqElemAppend(p: BProc, e: PNode, d: var TLoc) =
   # seq &= x  -->
@@ -1171,7 +1171,7 @@ proc binaryStmtInExcl(p: BProc, e: PNode, d: var TLoc, frmt: string) =
   assert(d.k == locNone)
   InitLocExpr(p, e.sons[1], a)
   InitLocExpr(p, e.sons[2], b)
-  appf(p.s[cpsStmts], frmt, [rdLoc(a), rdSetElemLoc(b, a.t)])
+  appf(p.s(cpsStmts), frmt, [rdLoc(a), rdSetElemLoc(b, a.t)])
 
 proc genInOp(p: BProc, e: PNode, d: var TLoc) =
   var a, b, x, y: TLoc
@@ -1247,7 +1247,7 @@ proc genSetOp(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
       initLocExpr(p, e.sons[1], a)
       initLocExpr(p, e.sons[2], b)
       if d.k == locNone: getTemp(p, a.t, d)
-      appf(p.s[cpsStmts], lookupOpr[op],
+      appf(p.s(cpsStmts), lookupOpr[op],
            [rdLoc(i), toRope(size), rdLoc(d), rdLoc(a), rdLoc(b)])
     of mEqSet:
       binaryExprChar(p, e, d, "(memcmp($1, $2, " & $(size) & ")==0)")
@@ -1257,7 +1257,7 @@ proc genSetOp(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
       initLocExpr(p, e.sons[1], a)
       initLocExpr(p, e.sons[2], b)
       if d.k == locNone: getTemp(p, a.t, d)
-      appf(p.s[cpsStmts],
+      appf(p.s(cpsStmts),
            "for ($1 = 0; $1 < $2; $1++) $n" & 
            "  $3[$1] = $4[$1] $6 $5[$1];$n", [
           rdLoc(i), toRope(size), rdLoc(d), rdLoc(a), rdLoc(b),
@@ -1467,35 +1467,35 @@ proc genSetConstr(p: BProc, e: PNode, d: var TLoc) =
     if d.k == locNone: getTemp(p, e.typ, d)
     if getSize(e.typ) > 8:
       # big set:
-      appf(p.s[cpsStmts], "memset($1, 0, sizeof($1));$n", [rdLoc(d)])
+      appf(p.s(cpsStmts), "memset($1, 0, sizeof($1));$n", [rdLoc(d)])
       for i in countup(0, sonsLen(e) - 1):
         if e.sons[i].kind == nkRange:
           getTemp(p, getSysType(tyInt), idx) # our counter
           initLocExpr(p, e.sons[i].sons[0], a)
           initLocExpr(p, e.sons[i].sons[1], b)
-          appf(p.s[cpsStmts], "for ($1 = $3; $1 <= $4; $1++) $n" &
+          appf(p.s(cpsStmts), "for ($1 = $3; $1 <= $4; $1++) $n" &
               "$2[$1/8] |=(1<<($1%8));$n", [rdLoc(idx), rdLoc(d),
               rdSetElemLoc(a, e.typ), rdSetElemLoc(b, e.typ)])
         else:
           initLocExpr(p, e.sons[i], a)
-          appf(p.s[cpsStmts], "$1[$2/8] |=(1<<($2%8));$n",
+          appf(p.s(cpsStmts), "$1[$2/8] |=(1<<($2%8));$n",
                [rdLoc(d), rdSetElemLoc(a, e.typ)])
     else:
       # small set
       var ts = "NI" & $(getSize(e.typ) * 8)
-      appf(p.s[cpsStmts], "$1 = 0;$n", [rdLoc(d)])
+      appf(p.s(cpsStmts), "$1 = 0;$n", [rdLoc(d)])
       for i in countup(0, sonsLen(e) - 1):
         if e.sons[i].kind == nkRange:
           getTemp(p, getSysType(tyInt), idx) # our counter
           initLocExpr(p, e.sons[i].sons[0], a)
           initLocExpr(p, e.sons[i].sons[1], b)
-          appf(p.s[cpsStmts], "for ($1 = $3; $1 <= $4; $1++) $n" &
+          appf(p.s(cpsStmts), "for ($1 = $3; $1 <= $4; $1++) $n" &
               "$2 |=(1<<((" & ts & ")($1)%(sizeof(" & ts & ")*8)));$n", [
               rdLoc(idx), rdLoc(d), rdSetElemLoc(a, e.typ),
               rdSetElemLoc(b, e.typ)])
         else:
           initLocExpr(p, e.sons[i], a)
-          appf(p.s[cpsStmts],
+          appf(p.s(cpsStmts),
                "$1 |=(1<<((" & ts & ")($2)%(sizeof(" & ts & ")*8)));$n",
                [rdLoc(d), rdSetElemLoc(a, e.typ)])
 
diff --git a/compiler/ccgmerge.nim b/compiler/ccgmerge.nim
index 36d1417a6..45463a397 100644
--- a/compiler/ccgmerge.nim
+++ b/compiler/ccgmerge.nim
@@ -280,7 +280,7 @@ proc mergeRequired*(m: BModule): bool =
       #echo "not empty: ", i, " ", ropeToStr(m.s[i])
       return true
   for i in low(TCProcSection)..high(TCProcSection):
-    if m.initProc.s[i] != nil: 
+    if m.initProc.s(i) != nil: 
       #echo "not empty: ", i, " ", ropeToStr(m.initProc.s[i])
       return true
 
@@ -292,5 +292,5 @@ proc mergeFiles*(cfilename: string, m: BModule) =
   for i in low(TCFileSection)..high(TCFileSection):
     m.s[i] = con(old.f[i], m.s[i])
   for i in low(TCProcSection)..high(TCProcSection):
-    m.initProc.s[i] = con(old.p[i], m.initProc.s[i])
+    m.initProc.s(i) = con(old.p[i], m.initProc.s(i))
 
diff --git a/compiler/ccgstmts.nim b/compiler/ccgstmts.nim
index 5ad9d8b44..9fd27bfeb 100755
--- a/compiler/ccgstmts.nim
+++ b/compiler/ccgstmts.nim
@@ -47,6 +47,51 @@ proc loadInto(p: BProc, le, ri: PNode, a: var TLoc) {.inline.} =
   else:
     expr(p, ri, a)
 
+proc startBlock(p: BProc, start: TFormatStr = "{$n",
+                args: openarray[PRope]): int {.discardable.} =
+  inc(p.labels)
+  result = len(p.blocks)
+  setlen(p.blocks, result + 1)
+  p.blocks[result].id = p.labels
+  p.blocks[result].nestedTryStmts = p.nestedTryStmts.len
+  appcg(p, cpsLocals, start, args)
+
+proc assignLabel(b: var TBlock): PRope {.inline.} =
+  b.label = con("LA", b.id.toRope)
+  result = b.label
+
+proc blockBody(b: var TBlock): PRope {.inline.} =
+  return b.sections[cpsLocals].con(b.sections[cpsInit]).con(b.sections[cpsStmts])
+
+proc endBlock(p: BProc, blockEnd: PRope) =
+  let topBlock = p.blocks.len - 1
+  # the block is merged into the parent block
+  app(p.blocks[topBlock - 1].sections[cpsStmts], p.blocks[topBlock].blockBody)
+  setlen(p.blocks, topBlock)
+  # this is done after the block is popped so $n is
+  # properly indented when pretty printing is enabled
+  app(p.s(cpsStmts), blockEnd)
+
+var gBlockEndBracket = ropef("}$n")
+
+proc endBlock(p: BProc) =
+  let topBlock = p.blocks.len - 1  
+  let blockEnd = if p.blocks[topBlock].label != nil:
+      ropef("} $1: ;$n", [p.blocks[topBlock].label])
+    else:
+      gBlockEndBracket
+  endBlock(p, blockEnd)
+
+proc genSimpleBlock(p: BProc, stmts: PNode) {.inline.} =
+  startBlock(p)
+  genStmts(p, stmts)
+  endBlock(p)
+
+template preserveBreakIdx(body: stmt): stmt =
+  var oldBreakIdx = p.breakIdx
+  body
+  p.breakIdx = oldBreakIdx
+
 proc genSingleVar(p: BProc, a: PNode) =
   var v = a.sons[0].sym
   if sfCompileTime in v.flags: return
@@ -56,7 +101,15 @@ proc genSingleVar(p: BProc, a: PNode) =
     if v.owner.kind != skModule:
       targetProc = p.module.preInitProc
     assignGlobalVar(targetProc, v)
-    genObjectInit(targetProc, cpsInit, v.typ, v.loc, true)
+    # XXX: be careful here.
+    # Global variables should not be zeromem-ed within loops 
+    # (see bug #20).
+    # That's why we are doing the construction inside the preInitProc.
+    # genObjectInit relies on the C runtime's guarantees that 
+    # global variables will be initialized to zero.
+    genObjectInit(p.module.preInitProc, cpsInit, v.typ, v.loc, true)
+    # Alternative construction using default constructor (which may zeromem):
+    # if sfImportc notin v.flags: constructLoc(p.module.preInitProc, v.loc)
   else:
     assignLocalVar(p, v)
     initLocalVar(p, v, immediateAsgn)
@@ -110,16 +163,15 @@ proc genConstStmt(p: BProc, t: PNode) =
 proc genIfStmt(p: BProc, n: PNode) = 
   #
   #  if (!expr1) goto L1;
-  #  thenPart
+  #  { thenPart }
   #  goto LEnd
   #  L1:
   #  if (!expr2) goto L2;
-  #  thenPart2
+  #  { thenPart2 }
   #  goto LEnd
   #  L2:
-  #  elsePart
+  #  { elsePart }
   #  Lend:
-  #
   var 
     a: TLoc
     Lelse: TLabel
@@ -132,15 +184,15 @@ proc genIfStmt(p: BProc, n: PNode) =
       initLocExpr(p, it.sons[0], a)
       Lelse = getLabel(p)
       inc(p.labels)
-      appff(p.s[cpsStmts], "if (!$1) goto $2;$n", 
+      appff(p.s(cpsStmts), "if (!$1) goto $2;$n", 
             "br i1 $1, label %LOC$3, label %$2$n" & "LOC$3: $n", 
             [rdLoc(a), Lelse, toRope(p.labels)])
-      genStmts(p, it.sons[1])
+      genSimpleBlock(p, it.sons[1])
       if sonsLen(n) > 1: 
-        appff(p.s[cpsStmts], "goto $1;$n", "br label %$1$n", [Lend])
+        appff(p.s(cpsStmts), "goto $1;$n", "br label %$1$n", [Lend])
       fixLabel(p, Lelse)
-    of nkElse: 
-      genStmts(p, it.sons[0])
+    of nkElse:
+      genSimpleBlock(p, it.sons[0])
     else: internalError(n.info, "genIfStmt()")
   if sonsLen(n) > 1: fixLabel(p, Lend)
   
@@ -169,65 +221,54 @@ proc genReturnStmt(p: BProc, t: PNode) =
   genLineDir(p, t)
   if (t.sons[0].kind != nkEmpty): genStmts(p, t.sons[0])
   blockLeaveActions(p, min(1, p.nestedTryStmts.len))
-  appff(p.s[cpsStmts], "goto BeforeRet;$n", "br label %BeforeRet$n", [])
-  
-proc genWhileStmt(p: BProc, t: PNode) = 
+  appff(p.s(cpsStmts), "goto BeforeRet;$n", "br label %BeforeRet$n", [])
+
+proc genWhileStmt(p: BProc, t: PNode) =
   # we don't generate labels here as for example GCC would produce
   # significantly worse code
   var 
     a: TLoc
     Labl: TLabel
-    length: int
+  assert(sonsLen(t) == 2)
   inc(p.withinLoop)
   genLineDir(p, t)
-  assert(sonsLen(t) == 2)
-  inc(p.labels)
-  Labl = con("LA", toRope(p.labels))
-  length = len(p.blocks)
-  setlen(p.blocks, length + 1)
-  p.blocks[length].id = - p.labels # negative because it isn't used yet
-  p.blocks[length].nestedTryStmts = p.nestedTryStmts.len
-  appf(p.s[cpsStmts], "while (1) {$n")
-  initLocExpr(p, t.sons[0], a)
-  if (t.sons[0].kind != nkIntLit) or (t.sons[0].intVal == 0): 
-    p.blocks[length].id = abs(p.blocks[length].id)
-    appf(p.s[cpsStmts], "if (!$1) goto $2;$n", [rdLoc(a), Labl])
-  genStmts(p, t.sons[1])
-  if p.blocks[length].id > 0: appf(p.s[cpsStmts], "} $1: ;$n", [Labl])
-  else: appf(p.s[cpsStmts], "}$n")
-  setlen(p.blocks, len(p.blocks) - 1)
-  dec(p.withinLoop)
 
-proc genBlock(p: BProc, t: PNode, d: var TLoc) = 
-  inc(p.labels)
-  var idx = len(p.blocks)
-  if t.sons[0].kind != nkEmpty: 
-    # named block?
-    assert(t.sons[0].kind == nkSym)
-    var sym = t.sons[0].sym
-    sym.loc.k = locOther
-    sym.loc.a = idx
-  setlen(p.blocks, idx + 1)
-  p.blocks[idx].id = -p.labels # negative because it isn't used yet
-  p.blocks[idx].nestedTryStmts = p.nestedTryStmts.len
-  if t.kind == nkBlockExpr: genStmtListExpr(p, t.sons[1], d)
-  else: genStmts(p, t.sons[1])
-  if p.blocks[idx].id > 0: 
-    appf(p.s[cpsStmts], "LA$1: ;$n", [toRope(p.blocks[idx].id)])
-  setlen(p.blocks, idx)
+  preserveBreakIdx:
+    p.breakIdx = startBlock(p, "while (1) {$n")
+    initLocExpr(p, t.sons[0], a)
+    if (t.sons[0].kind != nkIntLit) or (t.sons[0].intVal == 0): 
+      let label = assignLabel(p.blocks[p.breakIdx])
+      appf(p.s(cpsStmts), "if (!$1) goto $2;$n", [rdLoc(a), label])
+    genStmts(p, t.sons[1])
+    endBlock(p)
 
+  dec(p.withinLoop)
+
+proc genBlock(p: BProc, t: PNode, d: var TLoc) =
+  preserveBreakIdx:
+    p.breakIdx = startBlock(p)
+    if t.sons[0].kind != nkEmpty: 
+      # named block?
+      assert(t.sons[0].kind == nkSym)
+      var sym = t.sons[0].sym
+      sym.loc.k = locOther
+      sym.loc.a = p.breakIdx
+    if t.kind == nkBlockExpr: genStmtListExpr(p, t.sons[1], d)
+    else: genStmts(p, t.sons[1])
+    endBlock(p)
+  
 proc genBreakStmt(p: BProc, t: PNode) = 
-  var idx = len(p.blocks) - 1
+  var idx = p.breakIdx
   if t.sons[0].kind != nkEmpty: 
     # named break?
     assert(t.sons[0].kind == nkSym)
     var sym = t.sons[0].sym
     assert(sym.loc.k == locOther)
     idx = sym.loc.a
-  p.blocks[idx].id = abs(p.blocks[idx].id) # label is used
+  let label = assignLabel(p.blocks[idx])
   blockLeaveActions(p, p.nestedTryStmts.len - p.blocks[idx].nestedTryStmts)
   genLineDir(p, t)
-  appf(p.s[cpsStmts], "goto LA$1;$n", [toRope(p.blocks[idx].id)])
+  appf(p.s(cpsStmts), "goto $1;$n", [label])
 
 proc getRaiseFrmt(p: BProc): string = 
   #if gCmd == cmdCompileToCpp: 
@@ -269,13 +310,13 @@ proc genCaseGenericBranch(p: BProc, b: PNode, e: TLoc,
 proc genCaseSecondPass(p: BProc, t: PNode, labId, until: int): TLabel = 
   var Lend = getLabel(p)
   for i in 1..until: 
-    appf(p.s[cpsStmts], "LA$1: ;$n", [toRope(labId + i)])
+    appf(p.s(cpsStmts), "LA$1: ;$n", [toRope(labId + i)])
     if t.sons[i].kind == nkOfBranch:
       var length = sonsLen(t.sons[i])
-      genStmts(p, t.sons[i].sons[length - 1])
-      appf(p.s[cpsStmts], "goto $1;$n", [Lend])
+      genSimpleBlock(p, t.sons[i].sons[length - 1])
+      appf(p.s(cpsStmts), "goto $1;$n", [Lend])
     else: 
-      genStmts(p, t.sons[i].sons[0])
+      genSimpleBlock(p, t.sons[i].sons[0])
   result = Lend
 
 proc genIfForCaseUntil(p: BProc, t: PNode, rangeFormat, eqFormat: TFormatStr,
@@ -288,13 +329,13 @@ proc genIfForCaseUntil(p: BProc, t: PNode, rangeFormat, eqFormat: TFormatStr,
       genCaseGenericBranch(p, t.sons[i], a, rangeFormat, eqFormat, 
                            con("LA", toRope(p.labels)))
     else: 
-      appf(p.s[cpsStmts], "goto LA$1;$n", [toRope(p.labels)])
+      appf(p.s(cpsStmts), "goto LA$1;$n", [toRope(p.labels)])
   if until < t.len-1: 
     inc(p.labels)
     var gotoTarget = p.labels
-    appf(p.s[cpsStmts], "goto LA$1;$n", [toRope(gotoTarget)])
+    appf(p.s(cpsStmts), "goto LA$1;$n", [toRope(gotoTarget)])
     result = genCaseSecondPass(p, t, labId, until)
-    appf(p.s[cpsStmts], "LA$1: ;$n", [toRope(gotoTarget)])
+    appf(p.s(cpsStmts), "LA$1: ;$n", [toRope(gotoTarget)])
   else:
     result = genCaseSecondPass(p, t, labId, until)
 
@@ -346,11 +387,11 @@ proc genStringCase(p: BProc, t: PNode) =
         if interior != brn:
           echo "BUG! ", interior, "-", brn
       if branches[j] != nil:
-        appf(p.s[cpsStmts], "case $1: $n$2break;$n", 
+        appf(p.s(cpsStmts), "case $1: $n$2break;$n", 
              [intLiteral(j), branches[j]])
-    appf(p.s[cpsStmts], "}$n") # else statement:
+    appf(p.s(cpsStmts), "}$n") # else statement:
     if t.sons[sonsLen(t) - 1].kind != nkOfBranch: 
-      appf(p.s[cpsStmts], "goto LA$1;$n", [toRope(p.labels)]) 
+      appf(p.s(cpsStmts), "goto LA$1;$n", [toRope(p.labels)]) 
     # third pass: generate statements
     var Lend = genCaseSecondPass(p, t, labId, sonsLen(t)-1)
     fixLabel(p, Lend)
@@ -379,16 +420,16 @@ proc genCaseRange(p: BProc, branch: PNode) =
   for j in 0 .. length-2: 
     if branch[j].kind == nkRange: 
       if hasSwitchRange in CC[ccompiler].props: 
-        appf(p.s[cpsStmts], "case $1 ... $2:$n", [
+        appf(p.s(cpsStmts), "case $1 ... $2:$n", [
             genLiteral(p, branch[j][0]), 
             genLiteral(p, branch[j][1])])
       else: 
         var v = copyNode(branch[j][0])
         while v.intVal <= branch[j][1].intVal: 
-          appf(p.s[cpsStmts], "case $1:$n", [genLiteral(p, v)])
+          appf(p.s(cpsStmts), "case $1:$n", [genLiteral(p, v)])
           Inc(v.intVal)
     else:
-      appf(p.s[cpsStmts], "case $1:$n", [genLiteral(p, branch[j])])
+      appf(p.s(cpsStmts), "case $1:$n", [genLiteral(p, branch[j])])
 
 proc genOrdinalCase(p: BProc, n: PNode) = 
   # analyse 'case' statement:
@@ -404,22 +445,22 @@ proc genOrdinalCase(p: BProc, n: PNode) =
   
   # generate switch part (might be empty):
   if splitPoint+1 < n.len:
-    appf(p.s[cpsStmts], "switch ($1) {$n", [rdCharLoc(a)])
+    appf(p.s(cpsStmts), "switch ($1) {$n", [rdCharLoc(a)])
     var hasDefault = false
     for i in splitPoint+1 .. < n.len: 
       var branch = n[i]
       if branch.kind == nkOfBranch: 
         genCaseRange(p, branch)
-        genStmts(p, branch.lastSon)
+        genSimpleBlock(p, branch.lastSon)
       else: 
         # else part of case statement:
-        appf(p.s[cpsStmts], "default:$n")
-        genStmts(p, branch[0])
+        appf(p.s(cpsStmts), "default:$n")
+        genSimpleBlock(p, branch[0])
         hasDefault = true
-      appf(p.s[cpsStmts], "break;$n")
+      appf(p.s(cpsStmts), "break;$n")
     if (hasAssume in CC[ccompiler].props) and not hasDefault: 
-      appf(p.s[cpsStmts], "default: __assume(0);$n")
-    appf(p.s[cpsStmts], "}$n")
+      appf(p.s(cpsStmts), "default: __assume(0);$n")
+    appf(p.s(cpsStmts), "}$n")
   if Lend != nil: fixLabel(p, Lend)
   
 proc genCaseStmt(p: BProc, t: PNode) = 
@@ -466,6 +507,8 @@ proc genTryStmtCpp(p: BProc, t: PNode) =
   #  excHandler = excHandler->prev; // we handled the exception
   #  finallyPart();
   #  if (tmpRethrow) throw; 
+  #
+  #  XXX: push blocks
   var 
     rethrowFlag: PRope
     exc: PRope
@@ -475,43 +518,43 @@ proc genTryStmtCpp(p: BProc, t: PNode) =
   exc = getTempName()
   if not hasGeneralExceptSection(t): 
     rethrowFlag = getTempName()
-    appf(p.s[cpsLocals], "volatile NIM_BOOL $1 = NIM_FALSE;$n", [rethrowFlag])
+    appf(p.s(cpsLocals), "volatile NIM_BOOL $1 = NIM_FALSE;$n", [rethrowFlag])
   if optStackTrace in p.Options: 
     appcg(p, cpsStmts, "#setFrame((TFrame*)&F);$n")
-  appf(p.s[cpsStmts], "try {$n")
+  appf(p.s(cpsStmts), "try {$n")
   add(p.nestedTryStmts, t)
   genStmts(p, t.sons[0])
   length = sonsLen(t)
   if t.sons[1].kind == nkExceptBranch: 
-    appf(p.s[cpsStmts], "} catch (NimException& $1) {$n", [exc])
+    appf(p.s(cpsStmts), "} catch (NimException& $1) {$n", [exc])
     if rethrowFlag != nil: 
-      appf(p.s[cpsStmts], "$1 = NIM_TRUE;$n", [rethrowFlag])
-    appf(p.s[cpsStmts], "if ($1.sp.exc) {$n", [exc])
+      appf(p.s(cpsStmts), "$1 = NIM_TRUE;$n", [rethrowFlag])
+    appf(p.s(cpsStmts), "if ($1.sp.exc) {$n", [exc])
   i = 1
   while (i < length) and (t.sons[i].kind == nkExceptBranch): 
     blen = sonsLen(t.sons[i])
     if blen == 1: 
       # general except section:
-      appf(p.s[cpsStmts], "default:$n")
+      appf(p.s(cpsStmts), "default:$n")
       genStmts(p, t.sons[i].sons[0])
     else: 
       for j in countup(0, blen - 2): 
         assert(t.sons[i].sons[j].kind == nkType)
-        appf(p.s[cpsStmts], "case $1:$n", [toRope(t.sons[i].sons[j].typ.id)])
+        appf(p.s(cpsStmts), "case $1:$n", [toRope(t.sons[i].sons[j].typ.id)])
       genStmts(p, t.sons[i].sons[blen - 1])
     if rethrowFlag != nil: 
-      appf(p.s[cpsStmts], "$1 = NIM_FALSE;  ", [rethrowFlag])
-    appf(p.s[cpsStmts], "break;$n")
+      appf(p.s(cpsStmts), "$1 = NIM_FALSE;  ", [rethrowFlag])
+    appf(p.s(cpsStmts), "break;$n")
     inc(i)
   if t.sons[1].kind == nkExceptBranch: 
-    appf(p.s[cpsStmts], "}}$n") # end of catch-switch statement
+    appf(p.s(cpsStmts), "}}$n") # end of catch-switch statement
   appcg(p, cpsStmts, "#popSafePoint();")
   discard pop(p.nestedTryStmts)
   if (i < length) and (t.sons[i].kind == nkFinally): 
     genStmts(p, t.sons[i].sons[0])
   if rethrowFlag != nil: 
-    appf(p.s[cpsStmts], "if ($1) { throw; }$n", [rethrowFlag])
-  
+    appf(p.s(cpsStmts), "if ($1) { throw; }$n", [rethrowFlag])
+
 proc genTryStmt(p: BProc, t: PNode) = 
   # code to generate:
   #
@@ -531,10 +574,13 @@ proc genTryStmt(p: BProc, t: PNode) =
   #      clearException();
   #    }
   #  }
-  #  /* finally: */
-  #  printf('fin!\n');
+  #  { 
+  #    /* finally: */
+  #    printf('fin!\n');
+  #  }
   #  if (exception not cleared)
   #    propagateCurrentException();
+  #
   genLineDir(p, t)
   var safePoint = getTempName()
   discard cgsym(p.module, "E_Base")
@@ -543,24 +589,25 @@ proc genTryStmt(p: BProc, t: PNode) =
                      "$1.status = setjmp($1.context);$n", [safePoint])
   if optStackTrace in p.Options: 
     appcg(p, cpsStmts, "#setFrame((TFrame*)&F);$n")
-  appf(p.s[cpsStmts], "if ($1.status == 0) {$n", [safePoint])
+  startBlock(p, "if ($1.status == 0) {$n", [safePoint])
   var length = sonsLen(t)
   add(p.nestedTryStmts, t)
   genStmts(p, t.sons[0])
-  appcg(p, cpsStmts, "#popSafePoint();$n} else {$n#popSafePoint();$n")
+  endBlock(p, ropecg(p.module, "#popSafePoint();$n } else {$n#popSafePoint();$n"))
   discard pop(p.nestedTryStmts)
   var i = 1
   while (i < length) and (t.sons[i].kind == nkExceptBranch): 
     var blen = sonsLen(t.sons[i])
     if blen == 1: 
       # general except section:
-      if i > 1: appf(p.s[cpsStmts], "else {$n")
+      if i > 1: appf(p.s(cpsStmts), "else")
+      startBlock(p)
       appcg(p, cpsStmts, "$1.status = 0;$n", [safePoint])
       inc p.popCurrExc
       genStmts(p, t.sons[i].sons[0])
       dec p.popCurrExc
       appcg(p, cpsStmts, "#popCurrentException();$n", [])
-      if i > 1: appf(p.s[cpsStmts], "}$n")
+      endBlock(p)
     else:
       inc p.popCurrExc
       var orExpr: PRope = nil
@@ -570,17 +617,16 @@ proc genTryStmt(p: BProc, t: PNode) =
         appcg(p.module, orExpr, 
               "#isObj(#getCurrentException()->Sup.m_type, $1)", 
               [genTypeInfo(p.module, t.sons[i].sons[j].typ)])
-      if i > 1: app(p.s[cpsStmts], "else ")
-      appf(p.s[cpsStmts], "if ($1) {$n", [orExpr])
+      if i > 1: app(p.s(cpsStmts), "else ")
+      startBlock(p, "if ($1) {$n", [orExpr])
       appcg(p, cpsStmts, "$1.status = 0;$n", [safePoint])
       genStmts(p, t.sons[i].sons[blen-1])
       dec p.popCurrExc
-      # code to clear the exception:
-      appcg(p, cpsStmts, "#popCurrentException();}$n", [])
+      endBlock(p, ropecg(p.module, "#popCurrentException();}$n"))
     inc(i)
-  appf(p.s[cpsStmts], "}$n") # end of if statement
-  if i < length and t.sons[i].kind == nkFinally: 
-    genStmts(p, t.sons[i].sons[0])
+  appf(p.s(cpsStmts), "}$n") # end of else block
+  if i < length and t.sons[i].kind == nkFinally:
+    genSimpleBlock(p, t.sons[i].sons[0])
   appcg(p, cpsStmts, "if ($1.status != 0) #reraiseException();$n", [safePoint])
 
 proc genAsmOrEmitStmt(p: BProc, t: PNode): PRope = 
@@ -608,7 +654,7 @@ proc genAsmStmt(p: BProc, t: PNode) =
   assert(t.kind == nkAsmStmt)
   genLineDir(p, t)
   var s = genAsmOrEmitStmt(p, t)
-  appf(p.s[cpsStmts], CC[ccompiler].asmStmtFrmt, [s])
+  appf(p.s(cpsStmts), CC[ccompiler].asmStmtFrmt, [s])
 
 proc genEmit(p: BProc, t: PNode) = 
   genLineDir(p, t)
@@ -617,7 +663,7 @@ proc genEmit(p: BProc, t: PNode) =
     # top level emit pragma?
     app(p.module.s[cfsProcHeaders], s)
   else:
-    app(p.s[cpsStmts], s)
+    app(p.s(cpsStmts), s)
 
 var 
   breakPointId: int = 0
diff --git a/compiler/ccgthreadvars.nim b/compiler/ccgthreadvars.nim
index 18eaceb69..38c5c0f5e 100755
--- a/compiler/ccgthreadvars.nim
+++ b/compiler/ccgthreadvars.nim
@@ -10,6 +10,8 @@
 ## Thread var support for crappy architectures that lack native support for 
 ## thread local storage. (**Thank you Mac OS X!**)
 
+# included from cgen.nim
+
 proc emulatedThreadVars(): bool {.inline.} =
   result = {optThreads, optTlsEmulation} <= gGlobalOptions
 
@@ -17,8 +19,9 @@ proc AccessThreadLocalVar(p: BProc, s: PSym) =
   if emulatedThreadVars() and not p.ThreadVarAccessed:
     p.ThreadVarAccessed = true
     p.module.usesThreadVars = true
-    appf(p.s[cpsLocals], "NimThreadVars* NimTV;$n")
-    appcg(p, cpsInit, "NimTV=(NimThreadVars*)#GetThreadLocalVars();$n")
+    appf(p.procSec(cpsLocals), "NimThreadVars* NimTV;$n")
+    app(p.procSec(cpsInit),
+      ropecg(p.module, "NimTV=(NimThreadVars*)#GetThreadLocalVars();$n"))
 
 var
   nimtv: PRope                 # nimrod thread vars; the struct body
diff --git a/compiler/ccgtrav.nim b/compiler/ccgtrav.nim
index 8aaf5370f..d95ea8b09 100644
--- a/compiler/ccgtrav.nim
+++ b/compiler/ccgtrav.nim
@@ -10,6 +10,8 @@
 ## Generates traversal procs for the C backend. Traversal procs are only an
 ## optimization; the GC works without them too.
 
+# included from cgen.nim
+
 type
   TTraversalClosure {.pure, final.} = object
     p: BProc
@@ -29,17 +31,17 @@ proc genTraverseProc(c: var TTraversalClosure, accessor: PRope, n: PNode) =
     if (n.sons[0].kind != nkSym): InternalError(n.info, "genTraverseProc")
     var p = c.p
     let disc = n.sons[0].sym
-    p.s[cpsStmts].appf("switch ($1.$2) {$n", accessor, disc.loc.r)
+    p.s(cpsStmts).appf("switch ($1.$2) {$n", accessor, disc.loc.r)
     for i in countup(1, sonsLen(n) - 1):
       let branch = n.sons[i]
       assert branch.kind in {nkOfBranch, nkElse}
       if branch.kind == nkOfBranch:
         genCaseRange(c.p, branch)
       else:
-        p.s[cpsStmts].appf("default:$n")
+        p.s(cpsStmts).appf("default:$n")
       genTraverseProc(c, accessor, lastSon(branch))
-      p.s[cpsStmts].appf("break;$n")
-    p.s[cpsStmts].appf("} $n")
+      p.s(cpsStmts).appf("break;$n")
+    p.s(cpsStmts).appf("} $n")
   of nkSym:
     let field = n.sym
     genTraverseProc(c, ropef("$1.$2", accessor, field.loc.r), field.loc.t)
@@ -61,10 +63,10 @@ proc genTraverseProc(c: var TTraversalClosure, accessor: PRope, typ: PType) =
     let arraySize = lengthOrd(typ.sons[0])
     var i: TLoc
     getTemp(p, getSysType(tyInt), i)
-    appf(p.s[cpsStmts], "for ($1 = 0; $1 < $2; $1++) {$n",
+    appf(p.s(cpsStmts), "for ($1 = 0; $1 < $2; $1++) {$n",
         i.r, arraySize.toRope)
     genTraverseProc(c, ropef("$1[$2]", accessor, i.r), typ.sons[1])
-    appf(p.s[cpsStmts], "}$n")
+    appf(p.s(cpsStmts), "}$n")
   of tyObject:
     for i in countup(0, sonsLen(typ) - 1):
       genTraverseProc(c, accessor.parentObj, typ.sons[i])
@@ -87,10 +89,10 @@ proc genTraverseProcSeq(c: var TTraversalClosure, accessor: PRope, typ: PType) =
   assert typ.kind == tySequence  
   var i: TLoc
   getTemp(p, getSysType(tyInt), i)
-  appf(p.s[cpsStmts], "for ($1 = 0; $1 < $2->$3; $1++) {$n",
+  appf(p.s(cpsStmts), "for ($1 = 0; $1 < $2->$3; $1++) {$n",
       i.r, accessor, toRope(if gCmd != cmdCompileToCpp: "Sup.len" else: "len"))
   genTraverseProc(c, ropef("$1->data[$2]", accessor, i.r), typ.sons[0])
-  appf(p.s[cpsStmts], "}$n")
+  appf(p.s(cpsStmts), "}$n")
   
 proc genTraverseProc(m: BModule, typ: PType, reason: TTypeInfoReason): PRope =
   var c: TTraversalClosure
@@ -104,8 +106,8 @@ proc genTraverseProc(m: BModule, typ: PType, reason: TTypeInfoReason): PRope =
   let header = ropef("N_NIMCALL(void, $1)(void* p, NI op)", result)
   
   let t = getTypeDesc(m, typ)
-  p.s[cpsLocals].appf("$1 a;$n", t)
-  p.s[cpsInit].appf("a = ($1)p;$n", t)
+  p.s(cpsLocals).appf("$1 a;$n", t)
+  p.s(cpsInit).appf("a = ($1)p;$n", t)
   
   c.p = p
   if typ.kind == tySequence:
@@ -118,7 +120,7 @@ proc genTraverseProc(m: BModule, typ: PType, reason: TTypeInfoReason): PRope =
       genTraverseProc(c, "(*a)".toRope, typ.sons[0])
   
   let generatedProc = ropef("$1 {$n$2$3$4}$n",
-        [header, p.s[cpsLocals], p.s[cpsInit], p.s[cpsStmts]])
+        [header, p.s(cpsLocals), p.s(cpsInit), p.s(cpsStmts)])
   
   m.s[cfsProcHeaders].appf("$1;$n", header)
   m.s[cfsProcs].app(generatedProc)
diff --git a/compiler/ccgtypes.nim b/compiler/ccgtypes.nim
index 6195ff2f4..3578b1f5e 100755
--- a/compiler/ccgtypes.nim
+++ b/compiler/ccgtypes.nim
@@ -32,6 +32,15 @@ proc mangle(name: string): string =
       add(result, "HEX")
       add(result, toHex(ord(name[i]), 2))
 
+proc isCKeyword(w: PIdent): bool =
+  # nimrod and C++ share some keywords
+  # it's more efficient to test the whole nimrod keywords range
+  case w.id
+  of cppKeywordsLow..cppKeywordsHigh,
+     nimKeywordsLow..nimKeywordsHigh,
+     ord(wInline): return true
+  else: return false
+
 proc mangleName(s: PSym): PRope = 
   result = s.loc.r
   if result == nil: 
@@ -45,9 +54,64 @@ proc mangleName(s: PSym): PRope =
       of skTemp, skParam, skType, skEnumField, skModule: 
         result = toRope("%")
       else: InternalError(s.info, "mangleName")
-    app(result, toRope(mangle(s.name.s)))
-    app(result, "_")
-    app(result, toRope(s.id))
+    when oKeepVariableNames:
+      let keepOrigName = s.kind in skLocalVars - {skForVar} and 
+        {sfFromGeneric, sfGlobal, sfShadowed} * s.flags == {} and
+        not isCKeyword(s.name)
+      # XXX: This is still very experimental
+      #
+      # Even with all these inefficient checks, the bootstrap
+      # time is actually improved. This is probably because so many
+      # rope concatenations and are now eliminated.
+      #
+      # Future notes:
+      # sfFromGeneric seems to be needed in order to avoid multiple
+      # definitions of certain varialbes generated in transf with
+      # names such as:
+      # `r`, `res`
+      # I need to study where these come from.
+      #
+      # about sfShadowed:
+      # consider the following nimrod code:
+      #   var x = 10
+      #   block:
+      #     var x = something(x)
+      # The generated C code will be:
+      #   NI x;
+      #   x = 10;
+      #   {
+      #     NI x;
+      #     x = something(x); // Oops, x is already shadowed here
+      #   }
+      # Right now, we work-around by not keeping the original name
+      # of the shadowed variable, but we can do better - we can
+      # create an alternative reference to it in the outer scope and
+      # use that in the inner scope.
+      #
+      # about isCKeyword:
+      # nimrod variable names can be C keywords.
+      # We need to avoid such names in the generated code.
+      # XXX: Study whether mangleName is called just once per variable.
+      # Otherwise, there might be better place to do this.
+      #
+      # about sfGlobal:
+      # This seems to be harder - a top level extern variable from
+      # another modules can have the same name as a local one.
+      # Maybe we should just implement sfShadowed for them too.
+      #
+      # about skForVar:
+      # These are not properly scoped now - we need to add blocks
+      # around for loops in transf
+      if keepOrigName:
+        result = s.name.s.toRope
+      else:
+        app(result, toRope(mangle(s.name.s)))
+        app(result, "_")
+        app(result, toRope(s.id))
+    else:
+      app(result, toRope(mangle(s.name.s)))
+      app(result, "_")
+      app(result, toRope(s.id))
     s.loc.r = result
 
 proc isCompileTimeOnly(t: PType): bool =
diff --git a/compiler/cgen.nim b/compiler/cgen.nim
index de91205e2..e8073b555 100755
--- a/compiler/cgen.nim
+++ b/compiler/cgen.nim
@@ -151,7 +151,7 @@ proc appcg(m: BModule, s: TCFileSection, frmt: TFormatStr,
 
 proc appcg(p: BProc, s: TCProcSection, frmt: TFormatStr, 
            args: openarray[PRope]) = 
-  app(p.s[s], ropecg(p.module, frmt, args))
+  app(p.s(s), ropecg(p.module, frmt, args))
 
 proc safeLineNm(info: TLineInfo): int =
   result = toLinenumber(info)
@@ -168,14 +168,14 @@ proc genCLineDir(r: var PRope, info: TLineInfo) =
 
 proc genLineDir(p: BProc, t: PNode) = 
   var line = t.info.safeLineNm
-  genCLineDir(p.s[cpsStmts], t.info.toFullPath, line)
+  genCLineDir(p.s(cpsStmts), t.info.toFullPath, line)
   if ({optStackTrace, optEndb} * p.Options == {optStackTrace, optEndb}) and
       (p.prc == nil or sfPure notin p.prc.flags): 
     appcg(p, cpsStmts, "#endb($1);$n", [toRope(line)])
   elif ({optLineTrace, optStackTrace} * p.Options ==
       {optLineTrace, optStackTrace}) and
       (p.prc == nil or sfPure notin p.prc.flags): 
-    appf(p.s[cpsStmts], "F.line = $1;F.filename = $2;$n", 
+    appf(p.s(cpsStmts), "F.line = $1;F.filename = $2;$n", 
         [toRope(line), makeCString(toFilename(t.info).extractFilename)])
 
 include "ccgtypes.nim"
@@ -229,45 +229,37 @@ proc isComplexValueType(t: PType): bool {.inline.} =
   result = t.kind in {tyArray, tyArrayConstr, tySet, tyTuple, tyObject} or
     (t.kind == tyProc and t.callConv == ccClosure)
 
-proc zeroVar(p: BProc, loc: TLoc, containsGCref: bool) = 
+proc resetLoc(p: BProc, loc: var TLoc) =
+  let containsGcRef = containsGarbageCollectedRef(loc.t)
   if not isComplexValueType(skipTypes(loc.t, abstractVarRange)):
-    if containsGcref and p.WithInLoop > 0:
-      appf(p.s[cpsInit], "$1 = 0;$n", [rdLoc(loc)])
+    if containsGcRef:
       var nilLoc: TLoc
       initLoc(nilLoc, locTemp, loc.t, onStack)
       nilLoc.r = toRope("NIM_NIL")
-      # puts ``unsureAsgnRef`` etc to ``p.s[cpsStmts]``:
       genRefAssign(p, loc, nilLoc, {afSrcIsNil})
     else:
-      appf(p.s[cpsStmts], "$1 = 0;$n", [rdLoc(loc)])
+      appf(p.s(cpsStmts), "$1 = 0;$n", [rdLoc(loc)])
   else:
-    if containsGcref and p.WithInLoop > 0:
-      appf(p.s[cpsInit], "memset((void*)$1, 0, sizeof($2));$n", 
-           [addrLoc(loc), rdLoc(loc)])
-      genObjectInit(p, cpsInit, loc.t, loc, true)
-      appcg(p, cpsStmts, "#genericReset((void*)$1, $2);$n", 
-           [addrLoc(loc), genTypeInfo(p.module, loc.t)])
+    if loc.s != OnStack:
+      appcg(p, cpsStmts, "#genericReset((void*)$1, $2);$n",
+        [addrLoc(loc), genTypeInfo(p.module, loc.t)])
+      # XXX: generated reset procs should not touch the m_type
+      # field, so disabling this should be safe:
+      genObjectInit(p, cpsStmts, loc.t, loc, true)
     else:
-      appf(p.s[cpsStmts], "memset((void*)$1, 0, sizeof($2));$n", 
-           [addrLoc(loc), rdLoc(loc)])
+      appf(p.s(cpsStmts), "memset((void*)$1, 0, sizeof($2));$n",
+        [addrLoc(loc), rdLoc(loc)])
+      # XXX: We can be extra clever here and call memset only 
+      # on the bytes following the m_type field?
       genObjectInit(p, cpsStmts, loc.t, loc, true)
 
-proc zeroTemp(p: BProc, loc: TLoc) =
+proc constructLoc(p: BProc, loc: TLoc, section = cpsStmts) =
   if not isComplexValueType(skipTypes(loc.t, abstractVarRange)):
-    appf(p.s[cpsStmts], "$1 = 0;$n", [rdLoc(loc)])
-    when false:
-      var nilLoc: TLoc
-      initLoc(nilLoc, locTemp, loc.t, onStack)
-      nilLoc.r = toRope("NIM_NIL")
-      # puts ``unsureAsgnRef`` etc to ``p.s[cpsStmts]``:
-      genRefAssign(p, loc, nilLoc, {afSrcIsNil})
+    appf(p.s(section), "$1 = 0;$n", [rdLoc(loc)])
   else:
-    appf(p.s[cpsStmts], "memset((void*)$1, 0, sizeof($2));$n", 
-         [addrLoc(loc), rdLoc(loc)])
-    # XXX no object init necessary for temporaries?
-    when false:
-      appcg(p, cpsStmts, "#genericReset((void*)$1, $2);$n", 
-           [addrLoc(loc), genTypeInfo(p.module, loc.t)])
+    appf(p.s(section), "memset((void*)$1, 0, sizeof($2));$n",
+       [addrLoc(loc), rdLoc(loc)])
+    genObjectInit(p, section, loc.t, loc, true)
 
 proc initLocalVar(p: BProc, v: PSym, immediateAsgn: bool) =
   if sfNoInit notin v.flags:
@@ -279,11 +271,13 @@ proc initLocalVar(p: BProc, v: PSym, immediateAsgn: bool) =
     # ``var v = X()`` gets transformed into ``X(&v)``. 
     # Nowadays the logic in ccgcalls deals with this case however.
     if not immediateAsgn:
-      zeroVar(p, v.loc, containsGarbageCollectedRef(v.typ))
-    
-proc initTemp(p: BProc, tmp: var TLoc) = 
+      constructLoc(p, v.loc)
+
+proc initTemp(p: BProc, tmp: var TLoc) =
+  # XXX: This is still suspicious.
+  # Objects should always be constructed?
   if containsGarbageCollectedRef(tmp.t) or isInvalidReturnType(tmp.t):
-    zeroTemp(p, tmp)
+    constructLoc(p, tmp)
 
 proc getTemp(p: BProc, t: PType, result: var TLoc) = 
   inc(p.labels)
@@ -291,7 +285,7 @@ proc getTemp(p: BProc, t: PType, result: var TLoc) =
     result.r = con("%LOC", toRope(p.labels))
   else: 
     result.r = con("LOC", toRope(p.labels))
-    appf(p.s[cpsLocals], "$1 $2;$n", [getTypeDesc(p.module, t), result.r])
+    appf(p.s(cpsLocals), "$1 $2;$n", [getTypeDesc(p.module, t), result.r])
   result.k = locTemp
   result.a = - 1
   result.t = getUniqueType(t)
@@ -361,7 +355,7 @@ proc allocParam(p: BProc, s: PSym) =
     var tmp = con("%LOC", toRope(p.labels))
     incl(s.loc.flags, lfParamCopy)
     incl(s.loc.flags, lfIndirect)
-    appf(p.s[cpsInit], "$1 = alloca $3$n" & "store $3 $2, $3* $1$n", 
+    appf(p.s(cpsInit), "$1 = alloca $3$n" & "store $3 $2, $3* $1$n", 
          [tmp, s.loc.r, getTypeDesc(p.module, s.loc.t)])
     s.loc.r = tmp
 
@@ -371,7 +365,7 @@ proc localDebugInfo(p: BProc, s: PSym) =
   if skipTypes(s.typ, abstractVar).kind == tyOpenArray: return
   var a = con("&", s.loc.r)
   if (s.kind == skParam) and ccgIntroducedPtr(s): a = s.loc.r
-  appf(p.s[cpsInit], 
+  appf(p.s(cpsInit), 
        "F.s[$1].address = (void*)$3; F.s[$1].typ = $4; F.s[$1].name = $2;$n",
        [toRope(p.frameLen), makeCString(normalize(s.name.s)), a, 
         genTypeInfo(p.module, s.loc.t)])
@@ -384,13 +378,13 @@ proc assignLocalVar(p: BProc, s: PSym) =
   if s.loc.k == locNone: 
     fillLoc(s.loc, locLocalVar, s.typ, mangleName(s), OnStack)
     if s.kind == skLet: incl(s.loc.flags, lfNoDeepCopy)
-  app(p.s[cpsLocals], getTypeDesc(p.module, s.loc.t))
-  if sfRegister in s.flags: app(p.s[cpsLocals], " register")
+  app(p.s(cpsLocals), getTypeDesc(p.module, s.loc.t))
+  if sfRegister in s.flags: app(p.s(cpsLocals), " register")
   #elif skipTypes(s.typ, abstractInst).kind in GcTypeKinds:
   #  app(p.s[cpsLocals], " GC_GUARD")
   if (sfVolatile in s.flags) or (p.nestedTryStmts.len > 0): 
-    app(p.s[cpsLocals], " volatile")
-  appf(p.s[cpsLocals], " $1;$n", [s.loc.r])
+    app(p.s(cpsLocals), " volatile")
+  appf(p.s(cpsLocals), " $1;$n", [s.loc.r])
   localDebugInfo(p, s)
 
 include ccgthreadvars
@@ -410,7 +404,7 @@ proc assignGlobalVar(p: BProc, s: PSym) =
     appf(p.module.s[cfsVars], " $1;$n", [s.loc.r])
   if p.withinLoop > 0:
     # fixes tests/run/tzeroarray:
-    initLocalVar(p, s, false)
+    resetLoc(p, s.loc)
   if p.module.module.options * {optStackTrace, optEndb} ==
                                {optStackTrace, optEndb}: 
     appcg(p.module, p.module.s[cfsDebugInit], 
@@ -433,7 +427,7 @@ proc getLabel(p: BProc): TLabel =
   result = con("LA", toRope(p.labels))
 
 proc fixLabel(p: BProc, labl: TLabel) = 
-  appf(p.s[cpsStmts], "$1: ;$n", [labl])
+  appf(p.s(cpsStmts), "$1: ;$n", [labl])
 
 proc genVarPrototype(m: BModule, sym: PSym)
 proc requestConstImpl(p: BProc, sym: PSym)
@@ -481,9 +475,9 @@ proc loadDynamicLib(m: BModule, lib: PLib) =
       var p = newProc(nil, m)
       var dest: TLoc
       initLocExpr(p, lib.path, dest)
-      app(m.s[cfsVars], p.s[cpsLocals])
-      app(m.s[cfsDynLibInit], p.s[cpsInit])
-      app(m.s[cfsDynLibInit], p.s[cpsStmts])
+      app(m.s[cfsVars], p.s(cpsLocals))
+      app(m.s[cfsDynLibInit], p.s(cpsInit))
+      app(m.s[cfsDynLibInit], p.s(cpsStmts))
       appcg(m, m.s[cfsDynLibInit], 
            "if (!($1 = #nimLoadLibrary($2))) #nimLoadLibraryError($2);$n", 
            [tmp, rdLoc(dest)])
@@ -551,13 +545,13 @@ proc getFrameDecl(p: BProc) =
                    [toRope(p.frameLen)])
   else: 
     slots = nil
-  appff(p.s[cpsLocals], "volatile struct {TFrame* prev;" &
+  appff(p.s(cpsLocals), "volatile struct {TFrame* prev;" &
       "NCSTRING procname;NI line;NCSTRING filename;" & 
       "NI len;$n$1} F;$n", 
       "%TF = type {%TFrame*, i8*, %NI, %NI$1}$n" & 
       "%F = alloca %TF$n", [slots])
   inc(p.labels)
-  prepend(p.s[cpsInit], ropeff("F.len = $1;$n", 
+  prepend(p.s(cpsInit), ropeff("F.len = $1;$n", 
       "%LOC$2 = getelementptr %TF %F, %NI 4$n" &
       "store %NI $1, %NI* %LOC$2$n", [toRope(p.frameLen), toRope(p.labels)]))
 
@@ -613,32 +607,32 @@ proc genProcAux(m: BModule, prc: PSym) =
   var generatedProc: PRope
   if sfPure in prc.flags: 
     generatedProc = ropeff("$1 {$n$2$3$4}$n", "define $1 {$n$2$3$4}$n",
-        [header, p.s[cpsLocals], p.s[cpsInit], p.s[cpsStmts]])
+        [header, p.s(cpsLocals), p.s(cpsInit), p.s(cpsStmts)])
   else:
     generatedProc = ropeff("$1 {$n", "define $1 {$n", [header])
     app(generatedProc, initGCFrame(p))
     if optStackTrace in prc.options: 
       getFrameDecl(p)
-      app(generatedProc, p.s[cpsLocals])
+      app(generatedProc, p.s(cpsLocals))
       var procname = CStringLit(p, generatedProc, prc.name.s)
       var filename = CStringLit(p, generatedProc, toFilename(prc.info))
       app(generatedProc, initFrame(p, procname, filename))
     else: 
-      app(generatedProc, p.s[cpsLocals])
+      app(generatedProc, p.s(cpsLocals))
     if (optProfiler in prc.options) and (gCmd != cmdCompileToLLVM): 
       if gProcProfile >= 64 * 1024: 
         InternalError(prc.info, "too many procedures for profiling")
       discard cgsym(m, "profileData")
-      appf(p.s[cpsLocals], "ticks NIM_profilingStart;$n")
+      appf(p.s(cpsLocals), "ticks NIM_profilingStart;$n")
       if prc.loc.a < 0: 
         appf(m.s[cfsDebugInit], "profileData[$1].procname = $2;$n", [
             toRope(gProcProfile), 
             makeCString(prc.name.s)])
         prc.loc.a = gProcProfile
         inc(gProcProfile)
-      prepend(p.s[cpsInit], ropef("NIM_profilingStart = getticks();$n"))
-    app(generatedProc, p.s[cpsInit])
-    app(generatedProc, p.s[cpsStmts])
+      prepend(p.s(cpsInit), ropef("NIM_profilingStart = getticks();$n"))
+    app(generatedProc, p.s(cpsInit))
+    app(generatedProc, p.s(cpsStmts))
     if p.beforeRetNeeded: appf(generatedProc, "BeforeRet: $n;")
     app(generatedProc, deinitGCFrame(p))
     if optStackTrace in prc.options: app(generatedProc, deinitFrame(p))
@@ -858,8 +852,8 @@ proc genInitCode(m: BModule) =
   app(prc, initGCFrame(m.initProc))
   
   app(prc, genSectionStart(cpsLocals))
-  app(prc, m.initProc.s[cpsLocals])
-  app(prc, m.preInitProc.s[cpsLocals])
+  app(prc, m.initProc.s(cpsLocals))
+  app(prc, m.preInitProc.s(cpsLocals))
   app(prc, genSectionEnd(cpsLocals))
 
   app(prc, genSectionStart(cfsTypeInit1))
@@ -876,13 +870,13 @@ proc genInitCode(m: BModule) =
     app(prc, genSectionEnd(i))
   
   app(prc, genSectionStart(cpsInit))
-  app(prc, m.preInitProc.s[cpsInit])
-  app(prc, m.initProc.s[cpsInit])
+  app(prc, m.preInitProc.s(cpsInit))
+  app(prc, m.initProc.s(cpsInit))
   app(prc, genSectionEnd(cpsInit))
 
   app(prc, genSectionStart(cpsStmts))
-  app(prc, m.preInitProc.s[cpsStmts])
-  app(prc, m.initProc.s[cpsStmts])
+  app(prc, m.preInitProc.s(cpsStmts))
+  app(prc, m.initProc.s(cpsStmts))
   if optStackTrace in m.initProc.options and not m.PreventStackTrace:
     app(prc, deinitFrame(m.initProc))
   app(prc, genSectionEnd(cpsStmts))
diff --git a/compiler/cgendata.nim b/compiler/cgendata.nim
index fafccce18..f1463bbdc 100644
--- a/compiler/cgendata.nim
+++ b/compiler/cgendata.nim
@@ -48,13 +48,14 @@ type
   TCProcSections* = array[TCProcSection, PRope] # represents a generated C proc
   BModule* = ref TCGen
   BProc* = ref TCProc
-  TBlock{.final.} = object 
+  TBlock*{.final.} = object 
     id*: int                  # the ID of the label; positive means that it
-                              # has been used (i.e. the label should be emitted)
+    label*: PRope             # generated text for the label
+                              # nil if label is not used
     nestedTryStmts*: int      # how many try statements is it nested into
+    sections*: TCProcSections # the code beloging
   
   TCProc{.final.} = object    # represents C proc that is currently generated
-    s*: TCProcSections        # the procs sections; short name for readability
     prc*: PSym                # the Nimrod proc that this C proc belongs to
     BeforeRetNeeded*: bool    # true iff 'BeforeRet' label for proc is needed
     ThreadVarAccessed*: bool  # true if the proc already accessed some threadvar
@@ -64,6 +65,8 @@ type
                               # before 'break'|'return'
     labels*: Natural          # for generating unique labels in the C proc
     blocks*: seq[TBlock]      # nested blocks
+    breakIdx*: int            # the block that will be exited
+                              # with a regular break
     options*: TOptions        # options that should be used for code
                               # generation; this is the same as prc.options
                               # unless prc == nil
@@ -113,6 +116,13 @@ var
   gForwardedProcsCounter*: int = 0
   gNimDat*: BModule            # generated global data
 
+proc s*(p: BProc, s: TCProcSection): var PRope {.inline.} =
+  # section in the current block
+  result = p.blocks[p.blocks.len - 1].sections[s]
+
+proc procSec*(p: BProc, s: TCProcSection): var PRope {.inline.} =
+  # top level proc sections
+  result = p.blocks[0].sections[s]
 
 proc newProc*(prc: PSym, module: BModule): BProc = 
   new(result)
@@ -120,6 +130,6 @@ proc newProc*(prc: PSym, module: BModule): BProc =
   result.module = module
   if prc != nil: result.options = prc.options
   else: result.options = gOptions
-  result.blocks = @[]
+  newSeq(result.blocks, 1)
   result.nestedTryStmts = @[]
 
diff --git a/compiler/options.nim b/compiler/options.nim
index 0d7763be0..3a2352c7f 100755
--- a/compiler/options.nim
+++ b/compiler/options.nim
@@ -113,7 +113,9 @@ var
   gKeepComments*: bool = true # whether the parser needs to keep comments
   implicitImports*: seq[string] = @[] # modules that are to be implicitly imported
   implicitIncludes*: seq[string] = @[] # modules that are to be implicitly included
-  
+
+const oKeepVariableNames* = true
+
 proc mainCommandArg*: string =
   ## This is intended for commands like check or parse
   ## which will work on the main project file unless
diff --git a/compiler/semdata.nim b/compiler/semdata.nim
index 80aed2fd4..f97da4717 100755
--- a/compiler/semdata.nim
+++ b/compiler/semdata.nim
@@ -62,6 +62,7 @@ type
     AmbiguousSymbols*: TIntSet # ids of all ambiguous symbols (cannot
                                # store this info in the syms themselves!)
     InGenericContext*: int     # > 0 if we are in a generic
+    InUnrolledContext*: int    # > 0 if we are unrolling a loop
     converters*: TSymSeq       # sequence of converters
     optionStack*: TLinkedList
     libs*: TLinkedList         # all libs used by this module
diff --git a/compiler/semgnrc.nim b/compiler/semgnrc.nim
index 6a1c2f529..d8f017c4c 100755
--- a/compiler/semgnrc.nim
+++ b/compiler/semgnrc.nim
@@ -15,6 +15,8 @@
 # So we have to eval templates/macros right here so that symbol
 # lookup can be accurate.
 
+# included from sem.nim
+
 type 
   TSemGenericFlag = enum 
     withinBind, withinTypeDesc
diff --git a/compiler/semstmts.nim b/compiler/semstmts.nim
index 0449c5644..9e879ad0b 100755
--- a/compiler/semstmts.nim
+++ b/compiler/semstmts.nim
@@ -50,8 +50,8 @@ proc semIf(c: PContext, n: PNode): PNode =
     case it.kind
     of nkElifBranch: 
       checkSonsLen(it, 2)
-      openScope(c.tab)
       it.sons[0] = forceBool(c, semExprWithType(c, it.sons[0]))
+      openScope(c.tab)
       it.sons[1] = semStmt(c, it.sons[1])
       closeScope(c.tab)
     of nkElse: 
@@ -216,7 +216,13 @@ proc fitRemoveHiddenConv(c: PContext, typ: Ptype, n: PNode): PNode =
     result = result.sons[1]
   elif not sameType(result.typ, typ): 
     changeType(result, typ)
-  
+
+proc findShadowedVar(c: PContext, v: PSym): PSym =
+  for i in countdown(c.tab.tos - 2, 0):
+    let shadowed = StrTableGet(c.tab.stack[i], v.name)
+    if shadowed != nil and shadowed.kind in skLocalVars:
+      return shadowed
+
 proc semIdentDef(c: PContext, n: PNode, kind: TSymKind): PSym =
   if isTopLevel(c): 
     result = semIdentWithPragma(c, kind, n, {sfExported})
@@ -267,6 +273,11 @@ proc semVarOrLet(c: PContext, n: PNode, symkind: TSymKind): PNode =
     for j in countup(0, length-3):
       var v = semIdentDef(c, a.sons[j], symkind)
       addInterfaceDecl(c, v)
+      when oKeepVariableNames:
+        if c.InUnrolledContext > 0: v.flags.incl(sfShadowed)
+        else:
+          let shadowed = findShadowedVar(c, v)
+          if shadowed != nil: shadowed.flags.incl(sfShadowed)
       if def != nil and def.kind != nkEmpty:
         # this is only needed for the evaluation pass:
         v.ast = def
@@ -392,7 +403,9 @@ proc semForFields(c: PContext, n: PNode, m: TMagic): PNode =
     openScope(c.tab)
     var body = transfFieldLoopBody(loopBody, n, tupleTypeA, i,
                                    ord(m==mFieldPairs))
+    inc c.InUnrolledContext
     stmts.add(SemStmt(c, body))
+    dec c.InUnrolledContext
     closeScope(c.tab)
   Dec(c.p.nestedLoopCounter)
   var b = newNodeI(nkBreakStmt, n.info)
diff --git a/compiler/wordrecg.nim b/compiler/wordrecg.nim
index f96ba7751..3ae9f7be9 100755
--- a/compiler/wordrecg.nim
+++ b/compiler/wordrecg.nim
@@ -38,8 +38,8 @@ type
     wMagic, wThread, wFinal, wProfiler, wObjChecks,
     wImmediate, wImportCpp, wImportObjC,
     wImportCompilerProc,
-    wImportc, wExportc, wExtern, wIncompleteStruct,
-    wAlign, wNodecl, wPure, wVolatile, wRegister, wSideeffect, wHeader, 
+    wImportc, wExportc, wIncompleteStruct,
+    wAlign, wNodecl, wPure, wSideeffect, wHeader,
     wNosideeffect, wNoreturn, wMerge, wLib, wDynlib, wCompilerproc, wProcVar, 
     wFatal, wError, wWarning, wHint, wLine, wPush, wPop, wDefine, wUndef, 
     wLinedir, wStacktrace, wLinetrace, wLink, wCompile, 
@@ -58,13 +58,36 @@ type
     wWatchPoint, wSubsChar, 
     wAcyclic, wShallow, wUnroll, wLinearScanEnd,
     wWrite, wPutEnv, wPrependEnv, wAppendEnv, wThreadVar, wEmit, wNoStackFrame,
-    wImplicitStatic, wGlobal
+    wImplicitStatic, wGlobal,
+
+    wAuto, wBool, wCatch, wChar, wClass,
+    wConst_cast, wDefault, wDelete, wDouble, wDynamic_cast,
+    wExplicit, wExtern, wFalse, wFloat, wFriend,
+    wGoto, wInt, wLong, wMutable, wNamespace, wNew, wOperator,
+    wPrivate, wProtected, wPublic, wRegister, wReinterpret_cast,
+    wShort, wSigned, wSizeof, wStatic_cast, wStruct, wSwitch,
+    wThis, wThrow, wTrue, wTypedef, wTypeid, wTypename,
+    wUnion, wUnsigned, wUsing, wVirtual, wVoid, wVolatile, wWchar_t,
+
+    wAlignas, wAlignof, wConstexpr, wDecltype, wNullptr, wNoexcept,
+    wThread_local, wStatic_assert, wChar16_t, wChar32_t,
     
   TSpecialWords* = set[TSpecialWord]
 
 const 
   oprLow* = ord(wColon)
   oprHigh* = ord(wDotDot)
+  
+  nimKeywordsLow* = ord(wAsm)
+  nimKeywordsHigh* = ord(wYield)
+  
+  cppKeywordsLow* = ord(wAuto)
+  cppKeywordsHigh* = ord(wChar32_t)
+  
+  cppNimSharedKeywords* = {
+    wAsm, wBreak, wCase, wConst, wContinue, wDo, wElse, wEnum, wExport,
+    wFor, wIf, wReturn, wStatic, wTemplate, wTry, wWhile }
+
   specialWords*: array[low(TSpecialWord)..high(TSpecialWord), string] = ["", 
     
     "addr", "and", "as", "asm", "atomic", 
@@ -86,14 +109,14 @@ const
     "magic", "thread", "final", "profiler", "objchecks", 
     
     "immediate", "importcpp", "importobjc",
-    "importcompilerproc", "importc", "exportc", "extern", "incompletestruct",
-    "align", "nodecl", "pure", "volatile", "register", "sideeffect", 
+    "importcompilerproc", "importc", "exportc", "incompletestruct",
+    "align", "nodecl", "pure", "sideeffect",
     "header", "nosideeffect", "noreturn", "merge", "lib", "dynlib", 
     "compilerproc", "procvar", "fatal", "error", "warning", "hint", "line", 
     "push", "pop", "define", "undef", "linedir", "stacktrace", "linetrace", 
     "link", "compile", "linksys", "deprecated", "varargs", 
     "byref", "callconv", "breakpoint", "debugger", "nimcall", "stdcall", 
-    "cdecl", "safecall", "syscall", "inline", "noinline", "fastcall", "closure", 
+    "cdecl", "safecall", "syscall", "inline", "noinline", "fastcall", "closure",
     "noconv", "on", "off", "checks", "rangechecks", "boundchecks", 
     "overflowchecks", "nilchecks",
     "floatchecks", "nanchecks", "infchecks",
@@ -107,7 +130,22 @@ const
     "watchpoint",
     "subschar", "acyclic", "shallow", "unroll", "linearscanend",
     "write", "putenv", "prependenv", "appendenv", "threadvar", "emit",
-    "nostackframe", "implicitstatic", "global"]
+    "nostackframe", "implicitstatic", "global",
+    
+    "auto", "bool", "catch", "char", "class",
+    "const_cast", "default", "delete", "double",
+    "dynamic_cast", "explicit", "extern", "false",
+    "float", "friend", "goto", "int", "long", "mutable",
+    "namespace", "new", "operator",
+    "private", "protected", "public", "register", "reinterpret_cast",
+    "short", "signed", "sizeof", "static_cast", "struct", "switch",
+    "this", "throw", "true", "typedef", "typeid",
+    "typename", "union", "unsigned", "using", "virtual", "void", "volatile",
+    "wchar_t",
+
+    "alignas", "alignof", "constexpr", "decltype", "nullptr", "noexcept",
+    "thread_local", "static_assert", "char16_t", "char32_t",
+    ]
 
 proc findStr*(a: openarray[string], s: string): int = 
   for i in countup(low(a), high(a)):