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-rw-r--r--rod/semstmts.nim835
1 files changed, 0 insertions, 835 deletions
diff --git a/rod/semstmts.nim b/rod/semstmts.nim
deleted file mode 100644
index d2df06f3d..000000000
--- a/rod/semstmts.nim
+++ /dev/null
@@ -1,835 +0,0 @@
-#
-#
-#           The Nimrod Compiler
-#        (c) Copyright 2009 Andreas Rumpf
-#
-#    See the file "copying.txt", included in this
-#    distribution, for details about the copyright.
-#
-# this module does the semantic checking of statements
-
-proc semExprNoType(c: PContext, n: PNode): PNode =
-  result = semExpr(c, n)
-  if result.typ != nil and result.typ.kind != tyStmt:
-    liMessage(n.info, errDiscardValue)
-
-proc semWhen(c: PContext, n: PNode): PNode = 
-  result = nil
-  for i in countup(0, sonsLen(n) - 1): 
-    var it = n.sons[i]
-    if it == nil: illFormedAst(n)
-    case it.kind
-    of nkElifBranch: 
-      checkSonsLen(it, 2)
-      var e = semConstExpr(c, it.sons[0])
-      checkBool(e)
-      if (e.kind != nkIntLit): InternalError(n.info, "semWhen")
-      if (e.intVal != 0) and (result == nil): 
-        result = semStmt(c, it.sons[1]) # do not open a new scope!
-    of nkElse: 
-      checkSonsLen(it, 1)
-      if result == nil: 
-        result = semStmt(c, it.sons[0]) # do not open a new scope!
-    else: illFormedAst(n)
-  if result == nil: 
-    result = newNodeI(nkNilLit, n.info) 
-  # The ``when`` statement implements the mechanism for platform dependant
-  # code. Thus we try to ensure here consistent ID allocation after the
-  # ``when`` statement.
-  IDsynchronizationPoint(200)
-
-proc semIf(c: PContext, n: PNode): PNode = 
-  result = n
-  for i in countup(0, sonsLen(n) - 1): 
-    var it = n.sons[i]
-    if it == nil: illFormedAst(n)
-    case it.kind
-    of nkElifBranch: 
-      checkSonsLen(it, 2)
-      openScope(c.tab)
-      it.sons[0] = semExprWithType(c, it.sons[0])
-      checkBool(it.sons[0])
-      it.sons[1] = semStmt(c, it.sons[1])
-      closeScope(c.tab)
-    of nkElse: 
-      if sonsLen(it) == 1: it.sons[0] = semStmtScope(c, it.sons[0])
-      else: illFormedAst(it)
-    else: illFormedAst(n)
-  
-proc semDiscard(c: PContext, n: PNode): PNode = 
-  result = n
-  checkSonsLen(n, 1)
-  n.sons[0] = semExprWithType(c, n.sons[0])
-  if n.sons[0].typ == nil: liMessage(n.info, errInvalidDiscard)
-  
-proc semBreakOrContinue(c: PContext, n: PNode): PNode =
-  result = n
-  checkSonsLen(n, 1)
-  if n.sons[0] != nil: 
-    var s: PSym
-    case n.sons[0].kind
-    of nkIdent: s = lookUp(c, n.sons[0])
-    of nkSym: s = n.sons[0].sym
-    else: illFormedAst(n)
-    if (s.kind == skLabel) and (s.owner.id == c.p.owner.id): 
-      var x = newSymNode(s)
-      x.info = n.info
-      incl(s.flags, sfUsed)
-      n.sons[0] = x
-    else: 
-      liMessage(n.info, errInvalidControlFlowX, s.name.s)
-  elif (c.p.nestedLoopCounter <= 0) and (c.p.nestedBlockCounter <= 0): 
-    liMessage(n.info, errInvalidControlFlowX, renderTree(n, {renderNoComments}))
-  
-proc semBlock(c: PContext, n: PNode): PNode = 
-  result = n
-  Inc(c.p.nestedBlockCounter)
-  checkSonsLen(n, 2)
-  openScope(c.tab)            # BUGFIX: label is in the scope of block!
-  if n.sons[0] != nil: 
-    var labl = newSymS(skLabel, n.sons[0], c)
-    addDecl(c, labl)
-    n.sons[0] = newSymNode(labl) # BUGFIX
-  n.sons[1] = semStmt(c, n.sons[1])
-  closeScope(c.tab)
-  Dec(c.p.nestedBlockCounter)
-
-proc semAsm(con: PContext, n: PNode): PNode = 
-  result = n
-  checkSonsLen(n, 2)
-  var marker = pragmaAsm(con, n.sons[0])
-  if marker == '\0': marker = '`' # default marker
-  case n.sons[1].kind
-  of nkStrLit, nkRStrLit, nkTripleStrLit: 
-    result = copyNode(n)
-    var str = n.sons[1].strVal
-    if str == "": liMessage(n.info, errEmptyAsm) 
-    # now parse the string literal and substitute symbols:
-    var a = 0
-    while true: 
-      var b = strutils.find(str, marker, a)
-      var sub = if b < 0: copy(str, a) else: copy(str, a, b - 1)
-      if sub != "": addSon(result, newStrNode(nkStrLit, sub))
-      if b < 0: break 
-      var c = strutils.find(str, marker, b + 1)
-      if c < 0: sub = copy(str, b + 1)
-      else: sub = copy(str, b + 1, c - 1)
-      if sub != "": 
-        var e = SymtabGet(con.tab, getIdent(sub))
-        if e != nil: 
-          if e.kind == skStub: loadStub(e)
-          addSon(result, newSymNode(e))
-        else: 
-          addSon(result, newStrNode(nkStrLit, sub))
-      if c < 0: break 
-      a = c + 1
-  else: illFormedAst(n)
-  
-proc semWhile(c: PContext, n: PNode): PNode = 
-  result = n
-  checkSonsLen(n, 2)
-  openScope(c.tab)
-  n.sons[0] = semExprWithType(c, n.sons[0])
-  CheckBool(n.sons[0])
-  inc(c.p.nestedLoopCounter)
-  n.sons[1] = semStmt(c, n.sons[1])
-  dec(c.p.nestedLoopCounter)
-  closeScope(c.tab)
-
-proc semCase(c: PContext, n: PNode): PNode = 
-  # check selector:
-  result = n
-  checkMinSonsLen(n, 2)
-  openScope(c.tab)
-  n.sons[0] = semExprWithType(c, n.sons[0])
-  var chckCovered = false
-  var covered: biggestint = 0
-  case skipTypes(n.sons[0].Typ, abstractVarRange).Kind
-  of tyInt..tyInt64, tyChar, tyEnum: 
-    chckCovered = true
-  of tyFloat..tyFloat128, tyString: 
-    nil
-  else: liMessage(n.info, errSelectorMustBeOfCertainTypes)
-  for i in countup(1, sonsLen(n) - 1): 
-    var x = n.sons[i]
-    case x.kind
-    of nkOfBranch: 
-      checkMinSonsLen(x, 2)
-      semCaseBranch(c, n, x, i, covered)
-      var length = sonsLen(x)
-      x.sons[length - 1] = semStmtScope(c, x.sons[length - 1])
-    of nkElifBranch: 
-      chckCovered = false
-      checkSonsLen(x, 2)
-      x.sons[0] = semExprWithType(c, x.sons[0])
-      checkBool(x.sons[0])
-      x.sons[1] = semStmtScope(c, x.sons[1])
-    of nkElse: 
-      chckCovered = false
-      checkSonsLen(x, 1)
-      x.sons[0] = semStmtScope(c, x.sons[0])
-    else: illFormedAst(x)
-  if chckCovered and (covered != lengthOrd(n.sons[0].typ)): 
-    liMessage(n.info, errNotAllCasesCovered)
-  closeScope(c.tab)
-
-proc propertyWriteAccess(c: PContext, n, a: PNode): PNode = 
-  var id = considerAcc(a[1])
-  result = newNodeI(nkCall, n.info)
-  addSon(result, newIdentNode(getIdent(id.s & '='), n.info))
-  # a[0] is already checked for semantics, that does ``builtinFieldAccess``
-  # this is ugly. XXX Semantic checking should use the ``nfSem`` flag for
-  # nodes!
-  addSon(result, a[0])
-  addSon(result, semExpr(c, n[1]))
-  result = semDirectCallAnalyseEffects(c, result, {})
-  if result != nil:
-    fixAbstractType(c, result)
-    analyseIfAddressTakenInCall(c, result)
-  else:
-    liMessage(n.Info, errUndeclaredFieldX, id.s)
-
-proc semAsgn(c: PContext, n: PNode): PNode = 
-  checkSonsLen(n, 2)
-  var a = n.sons[0]
-  case a.kind
-  of nkDotExpr: 
-    # r.f = x
-    # --> `f=` (r, x)
-    a = builtinFieldAccess(c, a, {efLValue})
-    if a == nil: 
-      return propertyWriteAccess(c, n, n[0])
-    when false:
-      checkSonsLen(a, 2)
-      var id = considerAcc(a.sons[1])
-      result = newNodeI(nkCall, n.info)
-      addSon(result, newIdentNode(getIdent(id.s & '='), n.info))
-      addSon(result, semExpr(c, a.sons[0]))
-      addSon(result, semExpr(c, n.sons[1]))
-      result = semDirectCallAnalyseEffects(c, result, {})
-      if result != nil: 
-        fixAbstractType(c, result)
-        analyseIfAddressTakenInCall(c, result)
-        return 
-  of nkBracketExpr: 
-    # a[i..j] = x
-    # --> `[..]=`(a, i, j, x)
-    a = semSubscript(c, a, {efLValue})
-    if a == nil:
-      result = buildOverloadedSubscripts(n.sons[0], inAsgn=true)
-      add(result, n[1])
-      return semExprNoType(c, result)
-  else: 
-    a = semExprWithType(c, a, {efLValue})
-  #n.sons[0] = semExprWithType(c, n.sons[0], {efLValue})
-  n.sons[0] = a
-  n.sons[1] = semExprWithType(c, n.sons[1])
-  var le = a.typ
-  if skipTypes(le, {tyGenericInst}).kind != tyVar and IsAssignable(a) == arNone: 
-    # Direct assignment to a discriminant is allowed!
-    liMessage(a.info, errXCannotBeAssignedTo, renderTree(a, {renderNoComments}))
-  else: 
-    n.sons[1] = fitNode(c, le, n.sons[1])
-    fixAbstractType(c, n)
-  result = n
-
-proc SemReturn(c: PContext, n: PNode): PNode = 
-  var 
-    restype: PType
-    a: PNode                  # temporary assignment for code generator
-  result = n
-  checkSonsLen(n, 1)
-  if not (c.p.owner.kind in {skConverter, skMethod, skProc, skMacro}): 
-    liMessage(n.info, errXNotAllowedHere, "\'return\'")
-  if (n.sons[0] != nil): 
-    n.sons[0] = SemExprWithType(c, n.sons[0]) # check for type compatibility:
-    restype = c.p.owner.typ.sons[0]
-    if (restype != nil): 
-      a = newNodeI(nkAsgn, n.sons[0].info)
-      n.sons[0] = fitNode(c, restype, n.sons[0])
-      # optimize away ``return result``, because it would be transformed
-      # to ``result = result; return``:
-      if (n.sons[0].kind == nkSym) and (sfResult in n.sons[0].sym.flags): 
-        n.sons[0] = nil
-      else: 
-        if (c.p.resultSym == nil): InternalError(n.info, "semReturn")
-        addSon(a, semExprWithType(c, newSymNode(c.p.resultSym)))
-        addSon(a, n.sons[0])
-        n.sons[0] = a
-    else: 
-      liMessage(n.info, errCannotReturnExpr)
-  
-proc SemYield(c: PContext, n: PNode): PNode = 
-  var restype: PType
-  result = n
-  checkSonsLen(n, 1)
-  if (c.p.owner == nil) or (c.p.owner.kind != skIterator): 
-    liMessage(n.info, errYieldNotAllowedHere)
-  if (n.sons[0] != nil): 
-    n.sons[0] = SemExprWithType(c, n.sons[0]) # check for type compatibility:
-    restype = c.p.owner.typ.sons[0]
-    if (restype != nil): 
-      n.sons[0] = fitNode(c, restype, n.sons[0])
-      if (n.sons[0].typ == nil): InternalError(n.info, "semYield")
-    else: 
-      liMessage(n.info, errCannotReturnExpr)
-  
-proc fitRemoveHiddenConv(c: PContext, typ: Ptype, n: PNode): PNode = 
-  result = fitNode(c, typ, n)
-  if (result.kind in {nkHiddenStdConv, nkHiddenSubConv}): 
-    changeType(result.sons[1], typ)
-    result = result.sons[1]
-  elif not sameType(result.typ, typ): 
-    changeType(result, typ)
-  
-proc semVar(c: PContext, n: PNode): PNode = 
-  var 
-    length: int
-    a, b, def: PNode
-    typ, tup: PType
-    v: PSym
-  result = copyNode(n)
-  for i in countup(0, sonsLen(n) - 1): 
-    a = n.sons[i]
-    if a.kind == nkCommentStmt: continue 
-    if (a.kind != nkIdentDefs) and (a.kind != nkVarTuple): IllFormedAst(a)
-    checkMinSonsLen(a, 3)
-    length = sonsLen(a)
-    if a.sons[length - 2] != nil: typ = semTypeNode(c, a.sons[length - 2], nil)
-    else: typ = nil
-    if a.sons[length - 1] != nil: 
-      def = semExprWithType(c, a.sons[length - 1]) 
-      # BUGFIX: ``fitNode`` is needed here!
-      # check type compability between def.typ and typ:
-      if (typ != nil): def = fitNode(c, typ, def)
-      else: typ = def.typ
-    else: 
-      def = nil
-    if not typeAllowed(typ, skVar): 
-      #debug(typ);
-      liMessage(a.info, errXisNoType, typeToString(typ))
-    tup = skipTypes(typ, {tyGenericInst})
-    if a.kind == nkVarTuple: 
-      if tup.kind != tyTuple: liMessage(a.info, errXExpected, "tuple")
-      if length - 2 != sonsLen(tup): 
-        liMessage(a.info, errWrongNumberOfVariables)
-      b = newNodeI(nkVarTuple, a.info)
-      newSons(b, length)
-      b.sons[length - 2] = nil # no type desc
-      b.sons[length - 1] = def
-      addSon(result, b)
-    for j in countup(0, length - 3): 
-      if (c.p.owner.kind == skModule): 
-        v = semIdentWithPragma(c, skVar, a.sons[j], {sfStar, sfMinus})
-        incl(v.flags, sfGlobal)
-      else: 
-        v = semIdentWithPragma(c, skVar, a.sons[j], {})
-      if v.flags * {sfStar, sfMinus} != {}: incl(v.flags, sfInInterface)
-      addInterfaceDecl(c, v)
-      if a.kind != nkVarTuple: 
-        v.typ = typ
-        b = newNodeI(nkIdentDefs, a.info)
-        addSon(b, newSymNode(v))
-        addSon(b, nil)        # no type description
-        addSon(b, copyTree(def))
-        addSon(result, b)
-      else: 
-        v.typ = tup.sons[j]
-        b.sons[j] = newSymNode(v)
-
-proc semConst(c: PContext, n: PNode): PNode = 
-  var 
-    a, def, b: PNode
-    v: PSym
-    typ: PType
-  result = copyNode(n)
-  for i in countup(0, sonsLen(n) - 1): 
-    a = n.sons[i]
-    if a.kind == nkCommentStmt: continue 
-    if (a.kind != nkConstDef): IllFormedAst(a)
-    checkSonsLen(a, 3)
-    if (c.p.owner.kind == skModule): 
-      v = semIdentWithPragma(c, skConst, a.sons[0], {sfStar, sfMinus})
-      incl(v.flags, sfGlobal)
-    else: 
-      v = semIdentWithPragma(c, skConst, a.sons[0], {})
-    if a.sons[1] != nil: typ = semTypeNode(c, a.sons[1], nil)
-    else: typ = nil
-    def = semAndEvalConstExpr(c, a.sons[2]) 
-    # check type compability between def.typ and typ:
-    if (typ != nil): 
-      def = fitRemoveHiddenConv(c, typ, def)
-    else: 
-      typ = def.typ
-    if not typeAllowed(typ, skConst): 
-      liMessage(a.info, errXisNoType, typeToString(typ))
-    v.typ = typ
-    v.ast = def               # no need to copy
-    if v.flags * {sfStar, sfMinus} != {}: incl(v.flags, sfInInterface)
-    addInterfaceDecl(c, v)
-    b = newNodeI(nkConstDef, a.info)
-    addSon(b, newSymNode(v))
-    addSon(b, nil)            # no type description
-    addSon(b, copyTree(def))
-    addSon(result, b)
-
-proc semFor(c: PContext, n: PNode): PNode = 
-  var 
-    length: int
-    v, countup: PSym
-    iter: PType
-    countupNode, call: PNode
-  result = n
-  checkMinSonsLen(n, 3)
-  length = sonsLen(n)
-  openScope(c.tab)
-  if n.sons[length - 2].kind == nkRange: 
-    checkSonsLen(n.sons[length - 2], 2) 
-    # convert ``in 3..5`` to ``in countup(3, 5)``
-    countupNode = newNodeI(nkCall, n.sons[length - 2].info)
-    countUp = StrTableGet(magicsys.systemModule.Tab, getIdent("countup"))
-    if (countUp == nil): liMessage(countupNode.info, errSystemNeeds, "countup")
-    newSons(countupNode, 3)
-    countupnode.sons[0] = newSymNode(countup)
-    countupNode.sons[1] = n.sons[length - 2].sons[0]
-    countupNode.sons[2] = n.sons[length - 2].sons[1]
-    n.sons[length - 2] = countupNode
-  n.sons[length - 2] = semExprWithType(c, n.sons[length - 2], {efWantIterator})
-  call = n.sons[length - 2]
-  if (call.kind != nkCall) or (call.sons[0].kind != nkSym) or
-      (call.sons[0].sym.kind != skIterator): 
-    liMessage(n.sons[length - 2].info, errIteratorExpected)
-  iter = skipTypes(n.sons[length - 2].typ, {tyGenericInst})
-  if iter.kind != tyTuple: 
-    if length != 3: liMessage(n.info, errWrongNumberOfVariables)
-    v = newSymS(skForVar, n.sons[0], c)
-    v.typ = iter
-    n.sons[0] = newSymNode(v)
-    addDecl(c, v)
-  else: 
-    if length - 2 != sonsLen(iter): liMessage(n.info, errWrongNumberOfVariables)
-    for i in countup(0, length - 3): 
-      v = newSymS(skForVar, n.sons[i], c)
-      v.typ = iter.sons[i]
-      n.sons[i] = newSymNode(v)
-      addDecl(c, v)
-  Inc(c.p.nestedLoopCounter)
-  n.sons[length - 1] = SemStmt(c, n.sons[length - 1])
-  closeScope(c.tab)
-  Dec(c.p.nestedLoopCounter)
-
-proc semRaise(c: PContext, n: PNode): PNode = 
-  result = n
-  checkSonsLen(n, 1)
-  if n.sons[0] != nil: 
-    n.sons[0] = semExprWithType(c, n.sons[0])
-    var typ = n.sons[0].typ
-    if (typ.kind != tyRef) or (typ.sons[0].kind != tyObject): 
-      liMessage(n.info, errExprCannotBeRaised)
-  
-proc semTry(c: PContext, n: PNode): PNode = 
-  var check: TIntSet
-  result = n
-  checkMinSonsLen(n, 2)
-  n.sons[0] = semStmtScope(c, n.sons[0])
-  IntSetInit(check)
-  for i in countup(1, sonsLen(n) - 1): 
-    var a = n.sons[i]
-    checkMinSonsLen(a, 1)
-    var length = sonsLen(a)
-    if a.kind == nkExceptBranch: 
-      for j in countup(0, length - 2): 
-        var typ = semTypeNode(c, a.sons[j], nil)
-        if typ.kind == tyRef: typ = typ.sons[0]
-        if (typ.kind != tyObject): 
-          liMessage(a.sons[j].info, errExprCannotBeRaised)
-        a.sons[j] = newNodeI(nkType, a.sons[j].info)
-        a.sons[j].typ = typ
-        if IntSetContainsOrIncl(check, typ.id): 
-          liMessage(a.sons[j].info, errExceptionAlreadyHandled)
-    elif a.kind != nkFinally: 
-      illFormedAst(n) 
-    # last child of an nkExcept/nkFinally branch is a statement:
-    a.sons[length - 1] = semStmtScope(c, a.sons[length - 1])
-
-proc semGenericParamList(c: PContext, n: PNode, father: PType = nil): PNode = 
-  result = copyNode(n)
-  if n.kind != nkGenericParams: InternalError(n.info, "semGenericParamList")
-  for i in countup(0, sonsLen(n) - 1): 
-    var a = n.sons[i]
-    if a.kind != nkIdentDefs: illFormedAst(n)
-    var L = sonsLen(a)
-    var def = a.sons[L - 1]
-    var typ: PType
-    if a.sons[L - 2] != nil: typ = semTypeNode(c, a.sons[L - 2], nil)
-    elif def != nil: typ = newTypeS(tyExpr, c)
-    else: typ = nil
-    for j in countup(0, L - 3): 
-      var s: PSym
-      if (typ == nil) or (typ.kind == tyTypeDesc): 
-        s = newSymS(skType, a.sons[j], c)
-        s.typ = newTypeS(tyGenericParam, c)
-      else: 
-        s = newSymS(skGenericParam, a.sons[j], c)
-        s.typ = typ
-      s.ast = def
-      s.typ.sym = s
-      if father != nil: addSon(father, s.typ)
-      s.position = i
-      addSon(result, newSymNode(s))
-      addDecl(c, s)
-
-proc addGenericParamListToScope(c: PContext, n: PNode) = 
-  if n.kind != nkGenericParams: 
-    InternalError(n.info, "addGenericParamListToScope")
-  for i in countup(0, sonsLen(n) - 1): 
-    var a = n.sons[i]
-    if a.kind != nkSym: internalError(a.info, "addGenericParamListToScope")
-    addDecl(c, a.sym)
-
-proc SemTypeSection(c: PContext, n: PNode): PNode = 
-  var 
-    s: PSym
-    t, body: PType
-  result = n 
-  # process the symbols on the left side for the whole type section, before
-  # we even look at the type definitions on the right
-  for i in countup(0, sonsLen(n) - 1): 
-    var a = n.sons[i]
-    if a.kind == nkCommentStmt: continue 
-    if (a.kind != nkTypeDef): IllFormedAst(a)
-    checkSonsLen(a, 3)
-    if (c.p.owner.kind == skModule): 
-      s = semIdentWithPragma(c, skType, a.sons[0], {sfStar, sfMinus})
-      incl(s.flags, sfGlobal)
-    else: 
-      s = semIdentWithPragma(c, skType, a.sons[0], {})
-    if s.flags * {sfStar, sfMinus} != {}: incl(s.flags, sfInInterface)
-    s.typ = newTypeS(tyForward, c)
-    s.typ.sym = s             # process pragmas:
-    if a.sons[0].kind == nkPragmaExpr: 
-      pragma(c, s, a.sons[0].sons[1], typePragmas) 
-    # add it here, so that recursive types are possible:
-    addInterfaceDecl(c, s)
-    a.sons[0] = newSymNode(s)
-  for i in countup(0, sonsLen(n) - 1): 
-    var a = n.sons[i]
-    if a.kind == nkCommentStmt: continue 
-    if (a.kind != nkTypeDef): IllFormedAst(a)
-    checkSonsLen(a, 3)
-    if (a.sons[0].kind != nkSym): IllFormedAst(a)
-    s = a.sons[0].sym
-    if (s.magic == mNone) and (a.sons[2] == nil): 
-      liMessage(a.info, errImplOfXexpected, s.name.s)
-    if s.magic != mNone: processMagicType(c, s)
-    if a.sons[1] != nil: 
-      # We have a generic type declaration here. In generic types,
-      # symbol lookup needs to be done here.
-      openScope(c.tab)
-      pushOwner(s)
-      s.typ.kind = tyGenericBody
-      if s.typ.containerID != 0: 
-        InternalError(a.info, "semTypeSection: containerID")
-      s.typ.containerID = getID()
-      a.sons[1] = semGenericParamList(c, a.sons[1], s.typ)
-      addSon(s.typ, nil)      # to be filled out later
-      s.ast = a
-      body = semTypeNode(c, a.sons[2], nil)
-      if body != nil: body.sym = s
-      s.typ.sons[sonsLen(s.typ) - 1] = body #debug(s.typ);
-      popOwner()
-      closeScope(c.tab)
-    elif a.sons[2] != nil: 
-      # process the type's body:
-      pushOwner(s)
-      t = semTypeNode(c, a.sons[2], s.typ)
-      if (t != s.typ) and (s.typ != nil): 
-        internalError(a.info, "semTypeSection()")
-      s.typ = t
-      s.ast = a
-      popOwner()
-  for i in countup(0, sonsLen(n) - 1): 
-    var a = n.sons[i]
-    if a.kind == nkCommentStmt: continue 
-    if (a.sons[0].kind != nkSym): IllFormedAst(a)
-    s = a.sons[0].sym         
-    # compute the type's size and check for illegal recursions:
-    if a.sons[1] == nil: 
-      if (a.sons[2] != nil) and
-          (a.sons[2].kind in {nkSym, nkIdent, nkAccQuoted}): 
-        # type aliases are hard:
-        #MessageOut('for type ' + typeToString(s.typ));
-        t = semTypeNode(c, a.sons[2], nil)
-        if t.kind in {tyObject, tyEnum}: 
-          assignType(s.typ, t)
-          s.typ.id = t.id     # same id
-      checkConstructedType(s.info, s.typ)
-
-proc semParamList(c: PContext, n, genericParams: PNode, s: PSym) = 
-  s.typ = semProcTypeNode(c, n, genericParams, nil)
-
-proc addParams(c: PContext, n: PNode) = 
-  for i in countup(1, sonsLen(n) - 1): 
-    if (n.sons[i].kind != nkSym): InternalError(n.info, "addParams")
-    addDecl(c, n.sons[i].sym)
-
-proc semBorrow(c: PContext, n: PNode, s: PSym) = 
-  # search for the correct alias:
-  var b = SearchForBorrowProc(c, s, c.tab.tos - 2)
-  if b == nil: 
-    liMessage(n.info, errNoSymbolToBorrowFromFound) # store the alias:
-  n.sons[codePos] = newSymNode(b)
-
-proc sideEffectsCheck(c: PContext, s: PSym) = 
-  if {sfNoSideEffect, sfSideEffect} * s.flags ==
-      {sfNoSideEffect, sfSideEffect}: 
-    liMessage(s.info, errXhasSideEffects, s.name.s)
-  
-proc addResult(c: PContext, t: PType, info: TLineInfo) = 
-  if t != nil: 
-    var s = newSym(skVar, getIdent("result"), getCurrOwner())
-    s.info = info
-    s.typ = t
-    incl(s.flags, sfResult)
-    incl(s.flags, sfUsed)
-    addDecl(c, s)
-    c.p.resultSym = s
-
-proc addResultNode(c: PContext, n: PNode) = 
-  if c.p.resultSym != nil: addSon(n, newSymNode(c.p.resultSym))
-  
-proc semLambda(c: PContext, n: PNode): PNode = 
-  result = n
-  checkSonsLen(n, codePos + 1)
-  var s = newSym(skProc, getIdent(":anonymous"), getCurrOwner())
-  s.info = n.info
-  var oldP = c.p                  # restore later
-  s.ast = n
-  n.sons[namePos] = newSymNode(s)
-  pushOwner(s)
-  openScope(c.tab)
-  if (n.sons[genericParamsPos] != nil): 
-    illFormedAst(n)           # process parameters:
-  if n.sons[paramsPos] != nil: 
-    semParamList(c, n.sons[ParamsPos], nil, s)
-    addParams(c, s.typ.n)
-  else: 
-    s.typ = newTypeS(tyProc, c)
-    addSon(s.typ, nil)
-  s.typ.callConv = ccClosure
-  if n.sons[pragmasPos] != nil: pragma(c, s, n.sons[pragmasPos], lambdaPragmas)
-  s.options = gOptions
-  if n.sons[codePos] != nil: 
-    if sfImportc in s.flags: 
-      liMessage(n.sons[codePos].info, errImplOfXNotAllowed, s.name.s)
-    c.p = newProcCon(s)
-    addResult(c, s.typ.sons[0], n.info)
-    n.sons[codePos] = semStmtScope(c, n.sons[codePos])
-    addResultNode(c, n)
-  else: 
-    liMessage(n.info, errImplOfXexpected, s.name.s)
-  closeScope(c.tab)           # close scope for parameters
-  popOwner()
-  c.p = oldP                  # restore
-  result.typ = s.typ
-
-proc semProcAux(c: PContext, n: PNode, kind: TSymKind, 
-                validPragmas: TSpecialWords): PNode = 
-  var 
-    s, proto: PSym
-    gp: PNode
-  result = n
-  checkSonsLen(n, codePos + 1)
-  if c.p.owner.kind == skModule: 
-    s = semIdentVis(c, kind, n.sons[0], {sfStar})
-    incl(s.flags, sfGlobal)
-  else: 
-    s = semIdentVis(c, kind, n.sons[0], {})
-  n.sons[namePos] = newSymNode(s)
-  var oldP = c.p                  # restore later
-  if sfStar in s.flags: incl(s.flags, sfInInterface)
-  s.ast = n
-  pushOwner(s)
-  openScope(c.tab)
-  if n.sons[genericParamsPos] != nil: 
-    n.sons[genericParamsPos] = semGenericParamList(c, n.sons[genericParamsPos])
-    gp = n.sons[genericParamsPos]
-  else: 
-    gp = newNodeI(nkGenericParams, n.info) # process parameters:
-  if n.sons[paramsPos] != nil: 
-    semParamList(c, n.sons[ParamsPos], gp, s)
-    if sonsLen(gp) > 0: n.sons[genericParamsPos] = gp
-    addParams(c, s.typ.n)
-  else: 
-    s.typ = newTypeS(tyProc, c)
-    addSon(s.typ, nil)
-  proto = SearchForProc(c, s, c.tab.tos - 2) # -2 because we have a scope open
-                                             # for parameters
-  if proto == nil: 
-    if oldP.owner.kind != skModule: 
-      s.typ.callConv = ccClosure
-    else: 
-      s.typ.callConv = lastOptionEntry(c).defaultCC 
-    # add it here, so that recursive procs are possible:
-    # -2 because we have a scope open for parameters
-    if kind in OverloadableSyms: 
-      addInterfaceOverloadableSymAt(c, s, c.tab.tos - 2)
-    else: 
-      addDeclAt(c, s, c.tab.tos - 2)
-    if n.sons[pragmasPos] != nil: pragma(c, s, n.sons[pragmasPos], validPragmas)
-  else: 
-    if n.sons[pragmasPos] != nil: 
-      liMessage(n.sons[pragmasPos].info, errPragmaOnlyInHeaderOfProc)
-    if not (sfForward in proto.flags): 
-      liMessage(n.info, errAttemptToRedefineX, proto.name.s)
-    excl(proto.flags, sfForward)
-    closeScope(c.tab)         # close scope with wrong parameter symbols
-    openScope(c.tab)          # open scope for old (correct) parameter symbols
-    if proto.ast.sons[genericParamsPos] != nil: 
-      addGenericParamListToScope(c, proto.ast.sons[genericParamsPos])
-    addParams(c, proto.typ.n)
-    proto.info = s.info       # more accurate line information
-    s.typ = proto.typ
-    s = proto
-    n.sons[genericParamsPos] = proto.ast.sons[genericParamsPos]
-    n.sons[paramsPos] = proto.ast.sons[paramsPos]
-    if (n.sons[namePos].kind != nkSym): InternalError(n.info, "semProcAux")
-    n.sons[namePos].sym = proto
-    proto.ast = n             # needed for code generation
-    popOwner()
-    pushOwner(s)
-  s.options = gOptions
-  if n.sons[codePos] != nil: 
-    if {sfImportc, sfBorrow} * s.flags != {}: 
-      liMessage(n.sons[codePos].info, errImplOfXNotAllowed, s.name.s)
-    if (n.sons[genericParamsPos] == nil): 
-      c.p = newProcCon(s)
-      if (s.typ.sons[0] != nil) and (kind != skIterator): 
-        addResult(c, s.typ.sons[0], n.info)
-      n.sons[codePos] = semStmtScope(c, n.sons[codePos])
-      if (s.typ.sons[0] != nil) and (kind != skIterator): addResultNode(c, n)
-    else: 
-      if (s.typ.sons[0] != nil) and (kind != skIterator): 
-        addDecl(c, newSym(skUnknown, getIdent("result"), nil))
-      n.sons[codePos] = semGenericStmtScope(c, n.sons[codePos])
-  else: 
-    if proto != nil: liMessage(n.info, errImplOfXexpected, proto.name.s)
-    if {sfImportc, sfBorrow} * s.flags == {}: incl(s.flags, sfForward)
-    elif sfBorrow in s.flags: semBorrow(c, n, s)
-  sideEffectsCheck(c, s)
-  closeScope(c.tab)           # close scope for parameters
-  popOwner()
-  c.p = oldP                  # restore
-  
-proc semIterator(c: PContext, n: PNode): PNode = 
-  result = semProcAux(c, n, skIterator, iteratorPragmas)
-  var s = result.sons[namePos].sym
-  var t = s.typ
-  if t.sons[0] == nil: liMessage(n.info, errXNeedsReturnType, "iterator")
-  if n.sons[codePos] == nil: liMessage(n.info, errImplOfXexpected, s.name.s)
-  
-proc semProc(c: PContext, n: PNode): PNode = 
-  result = semProcAux(c, n, skProc, procPragmas)
-
-proc semMethod(c: PContext, n: PNode): PNode = 
-  if not isTopLevel(c): liMessage(n.info, errXOnlyAtModuleScope, "method")
-  result = semProcAux(c, n, skMethod, methodPragmas)
-
-proc semConverterDef(c: PContext, n: PNode): PNode = 
-  if not isTopLevel(c): liMessage(n.info, errXOnlyAtModuleScope, "converter")
-  checkSonsLen(n, codePos + 1)
-  if n.sons[genericParamsPos] != nil: 
-    liMessage(n.info, errNoGenericParamsAllowedForX, "converter")
-  result = semProcAux(c, n, skConverter, converterPragmas)
-  var s = result.sons[namePos].sym
-  var t = s.typ
-  if t.sons[0] == nil: liMessage(n.info, errXNeedsReturnType, "converter")
-  if sonsLen(t) != 2: liMessage(n.info, errXRequiresOneArgument, "converter")
-  addConverter(c, s)
-
-proc semMacroDef(c: PContext, n: PNode): PNode = 
-  checkSonsLen(n, codePos + 1)
-  if n.sons[genericParamsPos] != nil: 
-    liMessage(n.info, errNoGenericParamsAllowedForX, "macro")
-  result = semProcAux(c, n, skMacro, macroPragmas)
-  var s = result.sons[namePos].sym
-  var t = s.typ
-  if t.sons[0] == nil: liMessage(n.info, errXNeedsReturnType, "macro")
-  if sonsLen(t) != 2: liMessage(n.info, errXRequiresOneArgument, "macro")
-  if n.sons[codePos] == nil: liMessage(n.info, errImplOfXexpected, s.name.s)
-  
-proc evalInclude(c: PContext, n: PNode): PNode = 
-  result = newNodeI(nkStmtList, n.info)
-  addSon(result, n)           # the rodwriter needs include information!
-  for i in countup(0, sonsLen(n) - 1): 
-    var f = getModuleFile(n.sons[i])
-    var fileIndex = includeFilename(f)
-    if IntSetContainsOrIncl(c.includedFiles, fileIndex): 
-      liMessage(n.info, errRecursiveDependencyX, f)
-    addSon(result, semStmt(c, gIncludeFile(f)))
-    IntSetExcl(c.includedFiles, fileIndex)
-
-proc semCommand(c: PContext, n: PNode): PNode =
-  result = semExprNoType(c, n)
-  
-proc SemStmt(c: PContext, n: PNode): PNode = 
-  const                       # must be last statements in a block:
-    LastBlockStmts = {nkRaiseStmt, nkReturnStmt, nkBreakStmt, nkContinueStmt}
-  result = n
-  if n == nil: return 
-  if nfSem in n.flags: return 
-  case n.kind
-  of nkAsgn: result = semAsgn(c, n)
-  of nkCall, nkInfix, nkPrefix, nkPostfix, nkCommand, nkMacroStmt, nkCallStrLit: 
-    result = semCommand(c, n)
-  of nkEmpty, nkCommentStmt, nkNilLit: nil
-  of nkBlockStmt: result = semBlock(c, n)
-  of nkStmtList: 
-    var length = sonsLen(n)
-    for i in countup(0, length - 1): 
-      n.sons[i] = semStmt(c, n.sons[i])
-      if (n.sons[i].kind in LastBlockStmts): 
-        for j in countup(i + 1, length - 1): 
-          case n.sons[j].kind
-          of nkPragma, nkCommentStmt, nkNilLit, nkEmpty: 
-            nil
-          else: liMessage(n.sons[j].info, errStmtInvalidAfterReturn)
-  of nkRaiseStmt: result = semRaise(c, n)
-  of nkVarSection: result = semVar(c, n)
-  of nkConstSection: result = semConst(c, n)
-  of nkTypeSection: result = SemTypeSection(c, n)
-  of nkIfStmt: result = SemIf(c, n)
-  of nkWhenStmt: result = semWhen(c, n)
-  of nkDiscardStmt: result = semDiscard(c, n)
-  of nkWhileStmt: result = semWhile(c, n)
-  of nkTryStmt: result = semTry(c, n)
-  of nkBreakStmt, nkContinueStmt: result = semBreakOrContinue(c, n)
-  of nkForStmt: result = semFor(c, n)
-  of nkCaseStmt: result = semCase(c, n)
-  of nkReturnStmt: result = semReturn(c, n)
-  of nkAsmStmt: result = semAsm(c, n)
-  of nkYieldStmt: result = semYield(c, n)
-  of nkPragma: pragma(c, c.p.owner, n, stmtPragmas)
-  of nkIteratorDef: result = semIterator(c, n)
-  of nkProcDef: result = semProc(c, n)
-  of nkMethodDef: result = semMethod(c, n)
-  of nkConverterDef: result = semConverterDef(c, n)
-  of nkMacroDef: result = semMacroDef(c, n)
-  of nkTemplateDef: result = semTemplateDef(c, n)
-  of nkImportStmt: 
-    if not isTopLevel(c): liMessage(n.info, errXOnlyAtModuleScope, "import")
-    result = evalImport(c, n)
-  of nkFromStmt: 
-    if not isTopLevel(c): liMessage(n.info, errXOnlyAtModuleScope, "from")
-    result = evalFrom(c, n)
-  of nkIncludeStmt: 
-    if not isTopLevel(c): liMessage(n.info, errXOnlyAtModuleScope, "include")
-    result = evalInclude(c, n)
-  else: liMessage(n.info, errStmtExpected)
-  if result == nil: InternalError(n.info, "SemStmt: result = nil")
-  incl(result.flags, nfSem)
-
-proc semStmtScope(c: PContext, n: PNode): PNode = 
-  openScope(c.tab)
-  result = semStmt(c, n)
-  closeScope(c.tab)