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tclProc.c

/*
 * tclProc.c --
 *
 *    This file contains routines that implement Tcl procedures, including
 *    the "proc" and "uplevel" commands.
 *
 * Copyright (c) 1987-1993 The Regents of the University of California.
 * Copyright (c) 1994-1998 Sun Microsystems, Inc.
 * Copyright (c) 2004-2006 Miguel Sofer
 * Copyright (c) 2007 Daniel A. Steffen <das@users.sourceforge.net>
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclProc.c,v 1.139 2007/12/13 15:23:20 dgp Exp $
 */

#include "tclInt.h"
#include "tclCompile.h"

/*
 * Prototypes for static functions in this file
 */

static void       DupLambdaInternalRep(Tcl_Obj *objPtr,
                      Tcl_Obj *copyPtr);
static void       FreeLambdaInternalRep(Tcl_Obj *objPtr);
static int        InitArgsAndLocals(Tcl_Interp *interp,
                      Tcl_Obj *procNameObj, int skip);
static void       InitResolvedLocals(Tcl_Interp *interp,
                      ByteCode *codePtr, Var *defPtr,
                          Namespace *nsPtr);
static void             InitLocalCache(Proc *procPtr);
static int        PushProcCallFrame(ClientData clientData,
                      register Tcl_Interp *interp, int objc,
                      Tcl_Obj *CONST objv[], int isLambda);
static void       ProcBodyDup(Tcl_Obj *srcPtr, Tcl_Obj *dupPtr);
static void       ProcBodyFree(Tcl_Obj *objPtr);
static int              ProcWrongNumArgs(Tcl_Interp *interp, int skip);
static void       MakeProcError(Tcl_Interp *interp,
                      Tcl_Obj *procNameObj);
static void       MakeLambdaError(Tcl_Interp *interp,
                      Tcl_Obj *procNameObj);
static int        SetLambdaFromAny(Tcl_Interp *interp, Tcl_Obj *objPtr);
static int        ProcCompileProc(Tcl_Interp *interp, Proc *procPtr,
                      Tcl_Obj *bodyPtr, Namespace *nsPtr,
                      CONST char *description, CONST char *procName,
                      Proc **procPtrPtr);

/*
 * The ProcBodyObjType type
 */

Tcl_ObjType tclProcBodyType = {
    "procbody",               /* name for this type */
    ProcBodyFree,       /* FreeInternalRep function */
    ProcBodyDup,        /* DupInternalRep function */
    NULL,               /* UpdateString function; Tcl_GetString and
                         * Tcl_GetStringFromObj should panic
                         * instead. */
    NULL                /* SetFromAny function; Tcl_ConvertToType
                         * should panic instead. */
};

/*
 * The [upvar]/[uplevel] level reference type. Uses the twoPtrValue field,
 * encoding the type of level reference in ptr1 and the actual parsed out
 * offset in ptr2.
 *
 * Uses the default behaviour throughout, and never disposes of the string
 * rep; it's just a cache type.
 */

static Tcl_ObjType levelReferenceType = {
    "levelReference",
    NULL, NULL, NULL, NULL
};

/*
 * The type of lambdas. Note that every lambda will *always* have a string
 * representation.
 *
 * Internally, ptr1 is a pointer to a Proc instance that is not bound to a
 * command name, and ptr2 is a pointer to the namespace that the Proc instance
 * will execute within.
 */

static Tcl_ObjType lambdaType = {
    "lambdaExpr",       /* name */
    FreeLambdaInternalRep,    /* freeIntRepProc */
    DupLambdaInternalRep,     /* dupIntRepProc */
    NULL,               /* updateStringProc */
    SetLambdaFromAny          /* setFromAnyProc */
};

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ProcObjCmd --
 *
 *    This object-based function is invoked to process the "proc" Tcl
 *    command. See the user documentation for details on what it does.
 *
 * Results:
 *    A standard Tcl object result value.
 *
 * Side effects:
 *    A new procedure gets created.
 *
 *----------------------------------------------------------------------
 */

      /* ARGSUSED */
int
Tcl_ProcObjCmd(
    ClientData dummy,         /* Not used. */
    Tcl_Interp *interp,       /* Current interpreter. */
    int objc,                 /* Number of arguments. */
    Tcl_Obj *CONST objv[])    /* Argument objects. */
{
    register Interp *iPtr = (Interp *) interp;
    Proc *procPtr;
    char *fullName;
    CONST char *procName, *procArgs, *procBody;
    Namespace *nsPtr, *altNsPtr, *cxtNsPtr;
    Tcl_Command cmd;
    Tcl_DString ds;

    if (objc != 4) {
      Tcl_WrongNumArgs(interp, 1, objv, "name args body");
      return TCL_ERROR;
    }

    /*
     * Determine the namespace where the procedure should reside. Unless the
     * command name includes namespace qualifiers, this will be the current
     * namespace.
     */

    fullName = TclGetString(objv[1]);
    TclGetNamespaceForQualName(interp, fullName, NULL, 0,
          &nsPtr, &altNsPtr, &cxtNsPtr, &procName);

    if (nsPtr == NULL) {
      Tcl_AppendResult(interp, "can't create procedure \"", fullName,
            "\": unknown namespace", NULL);
      return TCL_ERROR;
    }
    if (procName == NULL) {
      Tcl_AppendResult(interp, "can't create procedure \"", fullName,
            "\": bad procedure name", NULL);
      return TCL_ERROR;
    }
    if ((nsPtr != iPtr->globalNsPtr)
          && (procName != NULL) && (procName[0] == ':')) {
      Tcl_AppendResult(interp, "can't create procedure \"", procName,
            "\" in non-global namespace with name starting with \":\"",
            NULL);
      return TCL_ERROR;
    }

    /*
     * Create the data structure to represent the procedure.
     */

    if (TclCreateProc(interp, nsPtr, procName, objv[2], objv[3],
          &procPtr) != TCL_OK) {
      Tcl_AddErrorInfo(interp, "\n    (creating proc \"");
      Tcl_AddErrorInfo(interp, procName);
      Tcl_AddErrorInfo(interp, "\")");
      return TCL_ERROR;
    }

    /*
     * Now create a command for the procedure. This will initially be in the
     * current namespace unless the procedure's name included namespace
     * qualifiers. To create the new command in the right namespace, we
     * generate a fully qualified name for it.
     */

    Tcl_DStringInit(&ds);
    if (nsPtr != iPtr->globalNsPtr) {
      Tcl_DStringAppend(&ds, nsPtr->fullName, -1);
      Tcl_DStringAppend(&ds, "::", 2);
    }
    Tcl_DStringAppend(&ds, procName, -1);

    cmd = Tcl_CreateObjCommand(interp, Tcl_DStringValue(&ds),
          TclObjInterpProc, (ClientData) procPtr, TclProcDeleteProc);

    Tcl_DStringFree(&ds);

    /*
     * Now initialize the new procedure's cmdPtr field. This will be used
     * later when the procedure is called to determine what namespace the
     * procedure will run in. This will be different than the current
     * namespace if the proc was renamed into a different namespace.
     */

    procPtr->cmdPtr = (Command *) cmd;

    /*
     * TIP #280: Remember the line the procedure body is starting on. In a
     * bytecode context we ask the engine to provide us with the necessary
     * information. This is for the initialization of the byte code compiler
     * when the body is used for the first time.
     *
     * This code is nearly identical to the #280 code in SetLambdaFromAny, see
     * this file. The differences are the different index of the body in the
     * line array of the context, and the lamdba code requires some special
     * processing. Find a way to factor the common elements into a single
     * function.
     */

    if (iPtr->cmdFramePtr) {
      CmdFrame *contextPtr;

      contextPtr = (CmdFrame *) TclStackAlloc(interp, sizeof(CmdFrame));
      *contextPtr = *iPtr->cmdFramePtr;

      if (contextPtr->type == TCL_LOCATION_BC) {
          /*
           * Retrieve source information from the bytecode, if possible. If
           * the information is retrieved successfully, context.type will be
           * TCL_LOCATION_SOURCE and the reference held by
           * context.data.eval.path will be counted.
           */

          TclGetSrcInfoForPc(contextPtr);
      } else if (contextPtr->type == TCL_LOCATION_SOURCE) {
          /*
           * The copy into 'context' up above has created another reference
           * to 'context.data.eval.path'; account for it.
           */

          Tcl_IncrRefCount(contextPtr->data.eval.path);
      }

      if (contextPtr->type == TCL_LOCATION_SOURCE) {
          /*
           * We can account for source location within a proc only if the
           * proc body was not created by substitution.
           */

          if (contextPtr->line
                && (contextPtr->nline >= 4) && (contextPtr->line[3] >= 0)) {
            int isNew;
            CmdFrame *cfPtr = (CmdFrame *) ckalloc(sizeof(CmdFrame));

            cfPtr->level = -1;
            cfPtr->type = contextPtr->type;
            cfPtr->line = (int *) ckalloc(sizeof(int));
            cfPtr->line[0] = contextPtr->line[3];
            cfPtr->nline = 1;
            cfPtr->framePtr = NULL;
            cfPtr->nextPtr = NULL;

            cfPtr->data.eval.path = contextPtr->data.eval.path;
            Tcl_IncrRefCount(cfPtr->data.eval.path);

            cfPtr->cmd.str.cmd = NULL;
            cfPtr->cmd.str.len = 0;

            Tcl_SetHashValue(Tcl_CreateHashEntry(iPtr->linePBodyPtr,
                  (char *) procPtr, &isNew), cfPtr);
          }

          /*
           * 'contextPtr' is going out of scope; account for the reference that
           * it's holding to the path name.
           */

          Tcl_DecrRefCount(contextPtr->data.eval.path);
          contextPtr->data.eval.path = NULL;
      }
      TclStackFree(interp, contextPtr);
    }

    /*
     * Optimize for no-op procs: if the body is not precompiled (like a TclPro
     * procbody), and the argument list is just "args" and the body is empty,
     * define a compileProc to compile a no-op.
     *
     * Notes:
     *       - cannot be done for any argument list without having different
     *         compiled/not-compiled behaviour in the "wrong argument #" case, or
     *         making this code much more complicated. In any case, it doesn't
     *         seem to make a lot of sense to verify the number of arguments we
     *         are about to ignore ...
     *       - could be enhanced to handle also non-empty bodies that contain only
     *         comments; however, parsing the body will slow down the compilation
     *         of all procs whose argument list is just _args_
     */

    if (objv[3]->typePtr == &tclProcBodyType) {
      goto done;
    }

    procArgs = TclGetString(objv[2]);

    while (*procArgs == ' ') {
      procArgs++;
    }

    if ((procArgs[0] == 'a') && (strncmp(procArgs, "args", 4) == 0)) {
      procArgs +=4;
      while(*procArgs != '\0') {
          if (*procArgs != ' ') {
            goto done;
          }
          procArgs++;
      }

      /*
       * The argument list is just "args"; check the body
       */

      procBody = TclGetString(objv[3]);
      while (*procBody != '\0') {
          if (!isspace(UCHAR(*procBody))) {
            goto done;
          }
          procBody++;
      }

      /*
       * The body is just spaces: link the compileProc
       */

      ((Command *) cmd)->compileProc = TclCompileNoOp;
    }

  done:
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclCreateProc --
 *
 *    Creates the data associated with a Tcl procedure definition. This
 *    function knows how to handle two types of body objects: strings and
 *    procbody. Strings are the traditional (and common) value for bodies,
 *    procbody are values created by extensions that have loaded a
 *    previously compiled script.
 *
 * Results:
 *    Returns TCL_OK on success, along with a pointer to a Tcl procedure
 *    definition in procPtrPtr where the cmdPtr field is not initialised.
 *    This definition should be freed by calling TclProcCleanupProc() when
 *    it is no longer needed. Returns TCL_ERROR if anything goes wrong.
 *
 * Side effects:
 *    If anything goes wrong, this function returns an error message in the
 *    interpreter.
 *
 *----------------------------------------------------------------------
 */

int
TclCreateProc(
    Tcl_Interp *interp,       /* Interpreter containing proc. */
    Namespace *nsPtr,         /* Namespace containing this proc. */
    CONST char *procName,     /* Unqualified name of this proc. */
    Tcl_Obj *argsPtr,         /* Description of arguments. */
    Tcl_Obj *bodyPtr,         /* Command body. */
    Proc **procPtrPtr)        /* Returns: pointer to proc data. */
{
    Interp *iPtr = (Interp *) interp;
    CONST char **argArray = NULL;

    register Proc *procPtr;
    int i, length, result, numArgs;
    CONST char *args, *bytes, *p;
    register CompiledLocal *localPtr = NULL;
    Tcl_Obj *defPtr;
    int precompiled = 0;

    if (bodyPtr->typePtr == &tclProcBodyType) {
      /*
       * Because the body is a TclProProcBody, the actual body is already
       * compiled, and it is not shared with anyone else, so it's OK not to
       * unshare it (as a matter of fact, it is bad to unshare it, because
       * there may be no source code).
       *
       * We don't create and initialize a Proc structure for the procedure;
       * rather, we use what is in the body object. We increment the ref
       * count of the Proc struct since the command (soon to be created)
       * will be holding a reference to it.
       */

      procPtr = bodyPtr->internalRep.otherValuePtr;
      procPtr->iPtr = iPtr;
      procPtr->refCount++;
      precompiled = 1;
    } else {
      /*
       * If the procedure's body object is shared because its string value
       * is identical to, e.g., the body of another procedure, we must
       * create a private copy for this procedure to use. Such sharing of
       * procedure bodies is rare but can cause problems. A procedure body
       * is compiled in a context that includes the number of "slots"
       * allocated by the compiler for local variables. There is a local
       * variable slot for each formal parameter (the
       * "procPtr->numCompiledLocals = numArgs" assignment below). This
       * means that the same code can not be shared by two procedures that
       * have a different number of arguments, even if their bodies are
       * identical. Note that we don't use Tcl_DuplicateObj since we would
       * not want any bytecode internal representation.
       */

      if (Tcl_IsShared(bodyPtr)) {
          bytes = TclGetStringFromObj(bodyPtr, &length);
          bodyPtr = Tcl_NewStringObj(bytes, length);
      }

      /*
       * Create and initialize a Proc structure for the procedure. We
       * increment the ref count of the procedure's body object since there
       * will be a reference to it in the Proc structure.
       */

      Tcl_IncrRefCount(bodyPtr);

      procPtr = (Proc *) ckalloc(sizeof(Proc));
      procPtr->iPtr = iPtr;
      procPtr->refCount = 1;
      procPtr->bodyPtr = bodyPtr;
      procPtr->numArgs = 0;   /* Actual argument count is set below. */
      procPtr->numCompiledLocals = 0;
      procPtr->firstLocalPtr = NULL;
      procPtr->lastLocalPtr = NULL;
    }

    /*
     * Break up the argument list into argument specifiers, then process each
     * argument specifier. If the body is precompiled, processing is limited
     * to checking that the parsed argument is consistent with the one stored
     * in the Proc.
     *
     * THIS FAILS IF THE ARG LIST OBJECT'S STRING REP CONTAINS NULS.
     */

    args = TclGetStringFromObj(argsPtr, &length);
    result = Tcl_SplitList(interp, args, &numArgs, &argArray);
    if (result != TCL_OK) {
      goto procError;
    }

    if (precompiled) {
      if (numArgs > procPtr->numArgs) {
          Tcl_SetObjResult(interp, Tcl_ObjPrintf(
                "procedure \"%s\": arg list contains %d entries, "
                "precompiled header expects %d", procName, numArgs,
                procPtr->numArgs));
          goto procError;
      }
      localPtr = procPtr->firstLocalPtr;
    } else {
      procPtr->numArgs = numArgs;
      procPtr->numCompiledLocals = numArgs;
    }

    for (i = 0; i < numArgs; i++) {
      int fieldCount, nameLength, valueLength;
      CONST char **fieldValues;

      /*
       * Now divide the specifier up into name and default.
       */

      result = Tcl_SplitList(interp, argArray[i], &fieldCount,
            &fieldValues);
      if (result != TCL_OK) {
          goto procError;
      }
      if (fieldCount > 2) {
          ckfree((char *) fieldValues);
          Tcl_AppendResult(interp,
                "too many fields in argument specifier \"",
                argArray[i], "\"", NULL);
          goto procError;
      }
      if ((fieldCount == 0) || (*fieldValues[0] == 0)) {
          ckfree((char *) fieldValues);
          Tcl_AppendResult(interp, "argument with no name", NULL);
          goto procError;
      }

      nameLength = strlen(fieldValues[0]);
      if (fieldCount == 2) {
          valueLength = strlen(fieldValues[1]);
      } else {
          valueLength = 0;
      }

      /*
       * Check that the formal parameter name is a scalar.
       */

      p = fieldValues[0];
      while (*p != '\0') {
          if (*p == '(') {
            CONST char *q = p;
            do {
                q++;
            } while (*q != '\0');
            q--;
            if (*q == ')') {  /* We have an array element. */
                Tcl_AppendResult(interp, "formal parameter \"",
                      fieldValues[0],
                      "\" is an array element", NULL);
                ckfree((char *) fieldValues);
                goto procError;
            }
          } else if ((*p == ':') && (*(p+1) == ':')) {
            Tcl_AppendResult(interp, "formal parameter \"",
                  fieldValues[0],
                  "\" is not a simple name", NULL);
            ckfree((char *) fieldValues);
            goto procError;
          }
          p++;
      }

      if (precompiled) {
          /*
           * Compare the parsed argument with the stored one. Note that the
           * only flag value that makes sense at this point is VAR_ARGUMENT
           * (its value was kept the same as pre VarReform to simplify
           * tbcload's processing of older byetcodes).
           *
           * The only other flag vlaue that is important to retrieve from
           * precompiled procs is VAR_TEMPORARY (also unchanged). It is
           * needed later when retrieving the variable names.
           */

          if ((localPtr->nameLength != nameLength)
                || (strcmp(localPtr->name, fieldValues[0]))
                || (localPtr->frameIndex != i)
                || !(localPtr->flags & VAR_ARGUMENT)
                || (localPtr->defValuePtr == NULL && fieldCount == 2)
                || (localPtr->defValuePtr != NULL && fieldCount != 2)) {
            Tcl_SetObjResult(interp, Tcl_ObjPrintf(
                  "procedure \"%s\": formal parameter %d is "
                  "inconsistent with precompiled body", procName, i));
            ckfree((char *) fieldValues);
            goto procError;
          }

          /*
           * Compare the default value if any.
           */

          if (localPtr->defValuePtr != NULL) {
            int tmpLength;
            char *tmpPtr = TclGetStringFromObj(localPtr->defValuePtr,
                  &tmpLength);

            if ((valueLength != tmpLength) ||
                  strncmp(fieldValues[1], tmpPtr, (size_t) tmpLength)) {
                Tcl_SetObjResult(interp, Tcl_ObjPrintf(
                      "procedure \"%s\": formal parameter \"%s\" has "
                      "default value inconsistent with precompiled body",
                      procName, fieldValues[0]));
                ckfree((char *) fieldValues);
                goto procError;
            }
          }
          if ((i == numArgs - 1)
                && (localPtr->nameLength == 4)
                && (localPtr->name[0] == 'a')
                && (strcmp(localPtr->name, "args") == 0)) {
            localPtr->flags |= VAR_IS_ARGS;
          }

          localPtr = localPtr->nextPtr;
      } else {
          /*
           * Allocate an entry in the runtime procedure frame's array of
           * local variables for the argument.
           */

          localPtr = (CompiledLocal *) ckalloc((unsigned)
                (sizeof(CompiledLocal) - sizeof(localPtr->name)
                      + nameLength + 1));
          if (procPtr->firstLocalPtr == NULL) {
            procPtr->firstLocalPtr = procPtr->lastLocalPtr = localPtr;
          } else {
            procPtr->lastLocalPtr->nextPtr = localPtr;
            procPtr->lastLocalPtr = localPtr;
          }
          localPtr->nextPtr = NULL;
          localPtr->nameLength = nameLength;
          localPtr->frameIndex = i;
          localPtr->flags = VAR_ARGUMENT;
          localPtr->resolveInfo = NULL;

          if (fieldCount == 2) {
            localPtr->defValuePtr =
                  Tcl_NewStringObj(fieldValues[1], valueLength);
            Tcl_IncrRefCount(localPtr->defValuePtr);
          } else {
            localPtr->defValuePtr = NULL;
          }
          strcpy(localPtr->name, fieldValues[0]);
          if ((i == numArgs - 1)
                && (localPtr->nameLength == 4)
                && (localPtr->name[0] == 'a')
                && (strcmp(localPtr->name, "args") == 0)) {
            localPtr->flags |= VAR_IS_ARGS;
          }
      }

      ckfree((char *) fieldValues);
    }

    *procPtrPtr = procPtr;
    ckfree((char *) argArray);
    return TCL_OK;

  procError:
    if (precompiled) {
      procPtr->refCount--;
    } else {
      Tcl_DecrRefCount(bodyPtr);
      while (procPtr->firstLocalPtr != NULL) {
          localPtr = procPtr->firstLocalPtr;
          procPtr->firstLocalPtr = localPtr->nextPtr;

          defPtr = localPtr->defValuePtr;
          if (defPtr != NULL) {
            Tcl_DecrRefCount(defPtr);
          }

          ckfree((char *) localPtr);
      }
      ckfree((char *) procPtr);
    }
    if (argArray != NULL) {
      ckfree((char *) argArray);
    }
    return TCL_ERROR;
}

/*
 *----------------------------------------------------------------------
 *
 * TclGetFrame --
 *
 *    Given a description of a procedure frame, such as the first argument
 *    to an "uplevel" or "upvar" command, locate the call frame for the
 *    appropriate level of procedure.
 *
 * Results:
 *    The return value is -1 if an error occurred in finding the frame (in
 *    this case an error message is left in the interp's result). 1 is
 *    returned if string was either a number or a number preceded by "#" and
 *    it specified a valid frame. 0 is returned if string isn't one of the
 *    two things above (in this case, the lookup acts as if string were
 *    "1"). The variable pointed to by framePtrPtr is filled in with the
 *    address of the desired frame (unless an error occurs, in which case it
 *    isn't modified).
 *
 * Side effects:
 *    None.
 *
 *----------------------------------------------------------------------
 */

int
TclGetFrame(
    Tcl_Interp *interp,       /* Interpreter in which to find frame. */
    CONST char *name,         /* String describing frame. */
    CallFrame **framePtrPtr)  /* Store pointer to frame here (or NULL if
                         * global frame indicated). */
{
    register Interp *iPtr = (Interp *) interp;
    int curLevel, level, result;
    CallFrame *framePtr;

    /*
     * Parse string to figure out which level number to go to.
     */

    result = 1;
    curLevel = iPtr->varFramePtr->level;
    if (*name== '#') {
      if (Tcl_GetInt(interp, name+1, &level) != TCL_OK || level < 0) {
          goto levelError;
      }
    } else if (isdigit(UCHAR(*name))) { /* INTL: digit */
      if (Tcl_GetInt(interp, name, &level) != TCL_OK) {
          goto levelError;
      }
      level = curLevel - level;
    } else {
      level = curLevel - 1;
      result = 0;
    }

    /*
     * Figure out which frame to use, and return it to the caller.
     */

    for (framePtr = iPtr->varFramePtr; framePtr != NULL;
          framePtr = framePtr->callerVarPtr) {
      if (framePtr->level == level) {
          break;
      }
    }
    if (framePtr == NULL) {
      goto levelError;
    }

    *framePtrPtr = framePtr;
    return result;

  levelError:
    Tcl_ResetResult(interp);
    Tcl_AppendResult(interp, "bad level \"", name, "\"", NULL);
    return -1;
}

/*
 *----------------------------------------------------------------------
 *
 * TclObjGetFrame --
 *
 *    Given a description of a procedure frame, such as the first argument
 *    to an "uplevel" or "upvar" command, locate the call frame for the
 *    appropriate level of procedure.
 *
 * Results:
 *    The return value is -1 if an error occurred in finding the frame (in
 *    this case an error message is left in the interp's result). 1 is
 *    returned if objPtr was either a number or a number preceded by "#" and
 *    it specified a valid frame. 0 is returned if objPtr isn't one of the
 *    two things above (in this case, the lookup acts as if objPtr were
 *    "1"). The variable pointed to by framePtrPtr is filled in with the
 *    address of the desired frame (unless an error occurs, in which case it
 *    isn't modified).
 *
 * Side effects:
 *    None.
 *
 *----------------------------------------------------------------------
 */

int
TclObjGetFrame(
    Tcl_Interp *interp,       /* Interpreter in which to find frame. */
    Tcl_Obj *objPtr,          /* Object describing frame. */
    CallFrame **framePtrPtr)  /* Store pointer to frame here (or NULL if
                         * global frame indicated). */
{
    register Interp *iPtr = (Interp *) interp;
    int curLevel, level, result;
    CallFrame *framePtr;
    CONST char *name = TclGetString(objPtr);

    /*
     * Parse object to figure out which level number to go to.
     */

    result = 1;
    curLevel = iPtr->varFramePtr->level;
    if (objPtr->typePtr == &levelReferenceType) {
      if (PTR2INT(objPtr->internalRep.twoPtrValue.ptr1)) {
          level = curLevel - PTR2INT(objPtr->internalRep.twoPtrValue.ptr2);
      } else {
          level = PTR2INT(objPtr->internalRep.twoPtrValue.ptr2);
      }
      if (level < 0) {
          goto levelError;
      }
      /* TODO: Consider skipping the typePtr checks */
    } else if (objPtr->typePtr == &tclIntType
#ifndef NO_WIDE_TYPE
          || objPtr->typePtr == &tclWideIntType
#endif
          ) {
      if (TclGetIntFromObj(NULL, objPtr, &level) != TCL_OK || level < 0) {
          goto levelError;
      }
      level = curLevel - level;
    } else if (*name == '#') {
      if (Tcl_GetInt(interp, name+1, &level) != TCL_OK || level < 0) {
          goto levelError;
      }

      /*
       * Cache for future reference.
       *
       * TODO: Use the new ptrAndLongRep intrep
       */

      TclFreeIntRep(objPtr);
      objPtr->typePtr = &levelReferenceType;
      objPtr->internalRep.twoPtrValue.ptr1 = (void *) 0;
      objPtr->internalRep.twoPtrValue.ptr2 = INT2PTR(level);
    } else if (isdigit(UCHAR(*name))) { /* INTL: digit */
      if (Tcl_GetInt(interp, name, &level) != TCL_OK) {
          return -1;
      }

      /*
       * Cache for future reference.
       *
       * TODO: Use the new ptrAndLongRep intrep
       */

      TclFreeIntRep(objPtr);
      objPtr->typePtr = &levelReferenceType;
      objPtr->internalRep.twoPtrValue.ptr1 = (void *) 1;
      objPtr->internalRep.twoPtrValue.ptr2 = INT2PTR(level);
      level = curLevel - level;
    } else {
      /*
       * Don't cache as the object *isn't* a level reference.
       */

      level = curLevel - 1;
      result = 0;
    }

    /*
     * Figure out which frame to use, and return it to the caller.
     */

    for (framePtr = iPtr->varFramePtr; framePtr != NULL;
          framePtr = framePtr->callerVarPtr) {
      if (framePtr->level == level) {
          break;
      }
    }
    if (framePtr == NULL) {
      goto levelError;
    }
    *framePtrPtr = framePtr;
    return result;

  levelError:
    Tcl_ResetResult(interp);
    Tcl_AppendResult(interp, "bad level \"", name, "\"", NULL);
    return -1;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_UplevelObjCmd --
 *
 *    This object function is invoked to process the "uplevel" Tcl command.
 *    See the user documentation for details on what it does.
 *
 * Results:
 *    A standard Tcl object result value.
 *
 * Side effects:
 *    See the user documentation.
 *
 *----------------------------------------------------------------------
 */

      /* ARGSUSED */
int
Tcl_UplevelObjCmd(
    ClientData dummy,         /* Not used. */
    Tcl_Interp *interp,       /* Current interpreter. */
    int objc,                 /* Number of arguments. */
    Tcl_Obj *CONST objv[])    /* Argument objects. */
{
    register Interp *iPtr = (Interp *) interp;
    int result;
    CallFrame *savedVarFramePtr, *framePtr;

    if (objc < 2) {
    uplevelSyntax:
      Tcl_WrongNumArgs(interp, 1, objv, "?level? command ?arg ...?");
      return TCL_ERROR;
    }

    /*
     * Find the level to use for executing the command.
     */

    result = TclObjGetFrame(interp, objv[1], &framePtr);
    if (result == -1) {
      return TCL_ERROR;
    }
    objc -= (result+1);
    if (objc == 0) {
      goto uplevelSyntax;
    }
    objv += (result+1);

    /*
     * Modify the interpreter state to execute in the given frame.
     */

    savedVarFramePtr = iPtr->varFramePtr;
    iPtr->varFramePtr = framePtr;

    /*
     * Execute the residual arguments as a command.
     */

    if (objc == 1) {
      result = Tcl_EvalObjEx(interp, objv[0], TCL_EVAL_DIRECT);
    } else {
      /*
       * More than one argument: concatenate them together with spaces
       * between, then evaluate the result. Tcl_EvalObjEx will delete the
       * object when it decrements its refcount after eval'ing it.
       */

      Tcl_Obj *objPtr;

      objPtr = Tcl_ConcatObj(objc, objv);
      result = Tcl_EvalObjEx(interp, objPtr, TCL_EVAL_DIRECT);
    }
    if (result == TCL_ERROR) {
      Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
            "\n    (\"uplevel\" body line %d)", interp->errorLine));
    }

    /*
     * Restore the variable frame, and return.
     */

    iPtr->varFramePtr = savedVarFramePtr;
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * TclFindProc --
 *
 *    Given the name of a procedure, return a pointer to the record
 *    describing the procedure. The procedure will be looked up using the
 *    usual rules: first in the current namespace and then in the global
 *    namespace.
 *
 * Results:
 *    NULL is returned if the name doesn't correspond to any procedure.
 *    Otherwise, the return value is a pointer to the procedure's record. If
 *    the name is found but refers to an imported command that points to a
 *    "real" procedure defined in another namespace, a pointer to that
 *    "real" procedure's structure is returned.
 *
 * Side effects:
 *    None.
 *
 *----------------------------------------------------------------------
 */

Proc *
TclFindProc(
    Interp *iPtr,       /* Interpreter in which to look. */
    CONST char *procName)     /* Name of desired procedure. */
{
    Tcl_Command cmd;
    Tcl_Command origCmd;
    Command *cmdPtr;

    cmd = Tcl_FindCommand((Tcl_Interp *) iPtr, procName, NULL, /*flags*/ 0);
    if (cmd == (Tcl_Command) NULL) {
      return NULL;
    }
    cmdPtr = (Command *) cmd;

    origCmd = TclGetOriginalCommand(cmd);
    if (origCmd != NULL) {
      cmdPtr = (Command *) origCmd;
    }
    if (cmdPtr->objProc != TclObjInterpProc) {
      return NULL;
    }
    return (Proc *) cmdPtr->objClientData;
}

/*
 *----------------------------------------------------------------------
 *
 * TclIsProc --
 *
 *    Tells whether a command is a Tcl procedure or not.
 *
 * Results:
 *    If the given command is actually a Tcl procedure, the return value is
 *    the address of the record describing the procedure. Otherwise the
 *    return value is 0.
 *
 * Side effects:
 *    None.
 *
 *----------------------------------------------------------------------
 */

Proc *
TclIsProc(
    Command *cmdPtr)          /* Command to test. */
{
    Tcl_Command origCmd;

    origCmd = TclGetOriginalCommand((Tcl_Command) cmdPtr);
    if (origCmd != NULL) {
      cmdPtr = (Command *) origCmd;
    }
    if (cmdPtr->objProc == TclObjInterpProc) {
      return (Proc *) cmdPtr->objClientData;
    }
    return (Proc *) 0;
}

/*
 *----------------------------------------------------------------------
 *
 * InitArgsAndLocals --
 *
 *    This routine is invoked in order to initialize the arguments and other
 *    compiled locals table for a new call frame.
 *
 * Results:
 *    A standard Tcl result.
 *
 * Side effects:
 *    Allocates memory on the stack for the compiled local variables, the
 *    caller is responsible for freeing them. Initialises all variables. May
 *    invoke various name resolvers in order to determine which variables
 *    are being referenced at runtime.
 *
 *----------------------------------------------------------------------
 */

static int
ProcWrongNumArgs(
    Tcl_Interp *interp, int skip)
{
    CallFrame *framePtr = ((Interp *)interp)->varFramePtr;
    register Proc *procPtr = framePtr->procPtr;
    register Var *defPtr;
    int localCt = procPtr->numCompiledLocals, numArgs, i;
    Tcl_Obj **desiredObjs;
    const char *final = NULL;
    
    /*
     * Build up desired argument list for Tcl_WrongNumArgs
     */

    numArgs = framePtr->procPtr->numArgs;
    desiredObjs = (Tcl_Obj **) TclStackAlloc(interp,
          (int) sizeof(Tcl_Obj *) * (numArgs+1));

#ifdef AVOID_HACKS_FOR_ITCL
    desiredObjs[0] = framePtr->objv[skip-1];
#else
    desiredObjs[0] = ((framePtr->isProcCallFrame & FRAME_IS_LAMBDA)
          ? framePtr->objv[skip-1]
          : Tcl_NewListObj(skip, framePtr->objv));
#endif /* AVOID_HACKS_FOR_ITCL */
    Tcl_IncrRefCount(desiredObjs[0]);

    defPtr = (Var *) (&framePtr->localCachePtr->varName0 + localCt);
    for (i=1 ; i<=numArgs ; i++, defPtr++) {
      Tcl_Obj *argObj;
      Tcl_Obj *namePtr = localName(framePtr, i-1);

      if (defPtr->value.objPtr != NULL) {
          TclNewObj(argObj);
          Tcl_AppendStringsToObj(argObj, "?", TclGetString(namePtr), "?", NULL);
      } else if (defPtr->flags & VAR_IS_ARGS) {
          numArgs--;
          final = "...";
          break;
      } else {
          argObj = namePtr;
          Tcl_IncrRefCount(namePtr);
      }
      desiredObjs[i] = argObj;
    }

    Tcl_ResetResult(interp);
    Tcl_WrongNumArgs(interp, numArgs+1, desiredObjs, final);

    for (i=0 ; i<=numArgs ; i++) {
      Tcl_DecrRefCount(desiredObjs[i]);
    }
    TclStackFree(interp, desiredObjs);
    return TCL_ERROR;
}

/*
 *----------------------------------------------------------------------
 *
 * TclInitCompiledLocals --
 *
 *    This routine is invoked in order to initialize the compiled locals
 *    table for a new call frame.
 *
 *    DEPRECATED: functionality has been inlined elsewhere; this function
 *    remains to insure binary compatibility with Itcl.
 *

 * Results:
 *    None.
 *
 * Side effects:
 *    May invoke various name resolvers in order to determine which
 *    variables are being referenced at runtime.
 *
 *----------------------------------------------------------------------
 */
void
TclInitCompiledLocals(
    Tcl_Interp *interp,       /* Current interpreter. */
    CallFrame *framePtr,      /* Call frame to initialize. */
    Namespace *nsPtr)         /* Pointer to current namespace. */
{
    Var *varPtr = framePtr->compiledLocals;
    Tcl_Obj *bodyPtr;
    ByteCode *codePtr;

    bodyPtr = framePtr->procPtr->bodyPtr;
    if (bodyPtr->typePtr != &tclByteCodeType) {
      Tcl_Panic("body object for proc attached to frame is not a byte code type");
    }
    codePtr = bodyPtr->internalRep.otherValuePtr;

    if (framePtr->numCompiledLocals) {
      if (!codePtr->localCachePtr) {
          InitLocalCache(framePtr->procPtr) ;
      }
      framePtr->localCachePtr = codePtr->localCachePtr;
      framePtr->localCachePtr->refCount++;
    }    

    InitResolvedLocals(interp, codePtr, varPtr, nsPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * InitResolvedLocals --
 *
 *    This routine is invoked in order to initialize the compiled locals
 *    table for a new call frame.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    May invoke various name resolvers in order to determine which
 *    variables are being referenced at runtime.
 *
 *----------------------------------------------------------------------
 */

static void
InitResolvedLocals(
    Tcl_Interp *interp,       /* Current interpreter. */
    ByteCode *codePtr,
    Var *varPtr,
    Namespace *nsPtr)         /* Pointer to current namespace. */
{
    Interp *iPtr = (Interp *) interp;
    int haveResolvers = (nsPtr->compiledVarResProc || iPtr->resolverPtr);
    CompiledLocal *firstLocalPtr, *localPtr;
    int varNum;
    Tcl_ResolvedVarInfo *resVarInfo;

    /*
     * Find the localPtr corresponding to varPtr
     */

    varNum = varPtr - iPtr->framePtr->compiledLocals;
    localPtr = iPtr->framePtr->procPtr->firstLocalPtr;
    while (varNum--) {
      localPtr = localPtr->nextPtr;
    }

    if (!(haveResolvers && (codePtr->flags & TCL_BYTECODE_RESOLVE_VARS))) {
      /*
       * Initialize the array of local variables stored in the call frame.
       * Some variables may have special resolution rules. In that case, we
       * call their "resolver" procs to get our hands on the variable, and
       * we make the compiled local a link to the real variable.
       */

    doInitResolvedLocals:
      for (; localPtr != NULL; varPtr++, localPtr = localPtr->nextPtr) {
          varPtr->flags = 0;
          varPtr->value.objPtr = NULL;
          
          /*
           * Now invoke the resolvers to determine the exact variables
           * that should be used.
           */
          
          resVarInfo = localPtr->resolveInfo;
          if (resVarInfo && resVarInfo->fetchProc) {
            Var *resolvedVarPtr = (Var *)
                (*resVarInfo->fetchProc)(interp, resVarInfo);
            if (resolvedVarPtr) {
                if (TclIsVarInHash(resolvedVarPtr)) {
                  VarHashRefCount(resolvedVarPtr)++;
                }
                varPtr->flags = VAR_LINK;
                varPtr->value.linkPtr = resolvedVarPtr;
            }
          }
      }
      return;
    }

    /*
     * This is the first run after a recompile, or else the resolver epoch
     * has changed: update the resolver cache.
     */
    
    firstLocalPtr = localPtr;
    for (; localPtr != NULL; localPtr = localPtr->nextPtr) {
      if (localPtr->resolveInfo) {
          if (localPtr->resolveInfo->deleteProc) {
            localPtr->resolveInfo->deleteProc(localPtr->resolveInfo);
          } else {
            ckfree((char *) localPtr->resolveInfo);
          }
          localPtr->resolveInfo = NULL;
      }
      localPtr->flags &= ~VAR_RESOLVED;
      
      if (haveResolvers &&
            !(localPtr->flags & (VAR_ARGUMENT|VAR_TEMPORARY))) {
          ResolverScheme *resPtr = iPtr->resolverPtr;
          Tcl_ResolvedVarInfo *vinfo;
          int result;
          
          if (nsPtr->compiledVarResProc) {
            result = (*nsPtr->compiledVarResProc)(nsPtr->interp,
                  localPtr->name, localPtr->nameLength,
                  (Tcl_Namespace *) nsPtr, &vinfo);
          } else {
            result = TCL_CONTINUE;
          }

          while ((result == TCL_CONTINUE) && resPtr) {
            if (resPtr->compiledVarResProc) {
                result = (*resPtr->compiledVarResProc)(nsPtr->interp,
                      localPtr->name, localPtr->nameLength,
                      (Tcl_Namespace *) nsPtr, &vinfo);
            }
            resPtr = resPtr->nextPtr;
          }
          if (result == TCL_OK) {
            localPtr->resolveInfo = vinfo;
            localPtr->flags |= VAR_RESOLVED;
          }
      }
    }
    localPtr = firstLocalPtr;
    codePtr->flags &= ~TCL_BYTECODE_RESOLVE_VARS;
    goto doInitResolvedLocals;
}

void
TclFreeLocalCache(
    Tcl_Interp *interp,
    LocalCache *localCachePtr)
{
    int i;
    Tcl_Obj **namePtrPtr = &localCachePtr->varName0;

    for (i = 0; i < localCachePtr->numVars; i++, namePtrPtr++) {
      Tcl_Obj *objPtr = *namePtrPtr;
      /*
       * Note that this can be called with interp==NULL, on interp 
       * deletion. In that case, the literal table and objects go away 
       * on their own.
       */
      if (objPtr) {
          if (interp) {
            TclReleaseLiteral(interp, objPtr);
          } else {
            Tcl_DecrRefCount(objPtr);
          }
      }
    }
    ckfree((char *) localCachePtr);
}

static void
InitLocalCache(Proc *procPtr)
{
    Interp *iPtr = procPtr->iPtr;
    ByteCode *codePtr = procPtr->bodyPtr->internalRep.otherValuePtr;
    int localCt = procPtr->numCompiledLocals;
    int numArgs = procPtr->numArgs, i = 0;

    Tcl_Obj **namePtr;
    Var *varPtr;
    LocalCache *localCachePtr;
    CompiledLocal *localPtr;
    int new;

    /*
     * Cache the names and initial values of local variables; store the
     * cache in both the framePtr for this execution and in the codePtr
     * for future calls.
     */

    localCachePtr = (LocalCache *) ckalloc(sizeof(LocalCache)
          + (localCt-1)*sizeof(Tcl_Obj *)
          + numArgs*sizeof(Var));

    namePtr = &localCachePtr->varName0;
    varPtr = (Var *) (namePtr + localCt);
    localPtr = procPtr->firstLocalPtr;
    while (localPtr) {
      if (TclIsVarTemporary(localPtr)) {
          *namePtr = NULL;
      } else {
          *namePtr = TclCreateLiteral(iPtr, localPtr->name,
                localPtr->nameLength, /* hash */ (unsigned int) -1,
                &new, /* nsPtr */ NULL, 0, NULL);
          Tcl_IncrRefCount(*namePtr);
      }

      if (i < numArgs) {
          varPtr->flags = (localPtr->flags & VAR_IS_ARGS);
          varPtr->value.objPtr = localPtr->defValuePtr;
          varPtr++;
          i++;
      }
      namePtr++;
      localPtr=localPtr->nextPtr;
    }
    codePtr->localCachePtr = localCachePtr;
    localCachePtr->refCount = 1;
    localCachePtr->numVars  = localCt;
}

static int
InitArgsAndLocals(
    register Tcl_Interp *interp,/* Interpreter in which procedure was
                         * invoked. */
    Tcl_Obj *procNameObj,     /* Procedure name for error reporting. */
    int skip)                 /* Number of initial arguments to be skipped,
                         * i.e., words in the "command name". */
{
    CallFrame *framePtr = ((Interp *)interp)->varFramePtr;
    register Proc *procPtr = framePtr->procPtr;
    ByteCode *codePtr = procPtr->bodyPtr->internalRep.otherValuePtr;
    register Var *varPtr, *defPtr;
    int localCt = procPtr->numCompiledLocals, numArgs, argCt, i, imax;
    Tcl_Obj *const *argObjs;
        
    /*
     * Make sure that the local cache of variable names and initial values has
     * been initialised properly .
     */

    if (localCt) {
      if (!codePtr->localCachePtr) {
          InitLocalCache(procPtr) ;
      }
      framePtr->localCachePtr = codePtr->localCachePtr;
      framePtr->localCachePtr->refCount++;
      defPtr = (Var *) (&framePtr->localCachePtr->varName0 + localCt);
    } else {
      defPtr = NULL;
    }
    
    /*
     * Create the "compiledLocals" array. Make sure it is large enough to hold
     * all the procedure's compiled local variables, including its formal
     * parameters.
     */

    varPtr = (Var*) TclStackAlloc(interp, (int)(localCt*sizeof(Var)));
    framePtr->compiledLocals = varPtr;
    framePtr->numCompiledLocals = localCt;

    /*
     * Match and assign the call's actual parameters to the procedure's formal
     * arguments. The formal arguments are described by the first numArgs
     * entries in both the Proc structure's local variable list and the call
     * frame's local variable array.
     */

    numArgs = procPtr->numArgs;
    argCt = framePtr->objc - skip;  /* Set it to the number of args to the
                               * procedure. */
    argObjs = framePtr->objv + skip;
    if (numArgs == 0) {
      if (argCt) {
          goto incorrectArgs;
      } else {
          goto correctArgs;
      }
    }
    imax = ((argCt < numArgs-1) ? argCt : numArgs-1);
    for (i = 0; i < imax; i++, varPtr++, defPtr++) {
      /*
       * "Normal" arguments; last formal is special, depends on it being
       * 'args'.
       */

      Tcl_Obj *objPtr = argObjs[i];

      varPtr->flags = 0;
      varPtr->value.objPtr = objPtr;
      Tcl_IncrRefCount(objPtr);     /* Local var is a reference. */
    }
    for (; i < numArgs-1; i++, varPtr++, defPtr++) {
      /*
       * This loop is entered if argCt < (numArgs-1). Set default values;
       * last formal is special.
       */

      Tcl_Obj *objPtr = defPtr->value.objPtr;

      if (objPtr) {
          varPtr->flags = 0;
          varPtr->value.objPtr = objPtr;
          Tcl_IncrRefCount(objPtr); /* Local var reference. */
      } else {
          goto incorrectArgs;
      }
    }

    /*
     * When we get here, the last formal argument remains to be defined:
     * defPtr and varPtr point to the last argument to be initialized.
     */


    varPtr->flags = 0;
    if (defPtr->flags & VAR_IS_ARGS) {
      Tcl_Obj *listPtr = Tcl_NewListObj(argCt-i, argObjs+i);

      varPtr->value.objPtr = listPtr;
      Tcl_IncrRefCount(listPtr);    /* Local var is a reference. */
    } else if (argCt == numArgs) {
      Tcl_Obj *objPtr = argObjs[i];

      varPtr->value.objPtr = objPtr;
      Tcl_IncrRefCount(objPtr);     /* Local var is a reference. */
    } else if ((argCt < numArgs) && (defPtr->value.objPtr != NULL)) {
      Tcl_Obj *objPtr = defPtr->value.objPtr;

      varPtr->value.objPtr = objPtr;
      Tcl_IncrRefCount(objPtr);     /* Local var is a reference. */
    } else {
      goto incorrectArgs;
    }
    varPtr++;

    /*
     * Initialise and resolve the remaining compiledLocals. In the absence of
     * resolvers, they are undefined local vars: (flags=0, value=NULL).
     */

  correctArgs:
    if (numArgs < localCt) {
      if (!framePtr->nsPtr->compiledVarResProc && !((Interp *)interp)->resolverPtr) {
          memset(varPtr, 0, (localCt - numArgs)*sizeof(Var));
      } else {
          InitResolvedLocals(interp, codePtr, varPtr, framePtr->nsPtr);
      }
    }

    return TCL_OK;


    incorrectArgs:
    /*
     * Initialise all compiled locals to avoid problems at DeleteLocalVars.
     */

    memset(varPtr, 0, ((framePtr->compiledLocals + localCt)-varPtr)*sizeof(Var));
    return ProcWrongNumArgs(interp, skip);
}

/*
 *----------------------------------------------------------------------
 *
 * PushProcCallFrame --
 *
 *    Compiles a proc body if necessary, then pushes a CallFrame suitable
 *    for executing it.
 *
 * Results:
 *    A standard Tcl object result value.
 *
 * Side effects:
 *    The proc's body may be recompiled. A CallFrame is pushed, it will have
 *    to be popped by the caller.
 *
 *----------------------------------------------------------------------
 */

static int
PushProcCallFrame(
    ClientData clientData,    /* Record describing procedure to be
                         * interpreted. */
    register Tcl_Interp *interp,/* Interpreter in which procedure was
                         * invoked. */
    int objc,                 /* Count of number of arguments to this
                         * procedure. */
    Tcl_Obj *CONST objv[],    /* Argument value objects. */
    int isLambda)       /* 1 if this is a call by ApplyObjCmd: it
                         * needs special rules for error msg */
{
    Proc *procPtr = (Proc *) clientData;
    Namespace *nsPtr = procPtr->cmdPtr->nsPtr;
    CallFrame *framePtr, **framePtrPtr;
    int result;
    ByteCode *codePtr;

    /*
     * If necessary (i.e. if we haven't got a suitable compilation already
     * cached) compile the procedure's body. The compiler will allocate frame
     * slots for the procedure's non-argument local variables. Note that
     * compiling the body might increase procPtr->numCompiledLocals if new
     * local variables are found while compiling.
     */

    if (procPtr->bodyPtr->typePtr == &tclByteCodeType) {
      Interp *iPtr = (Interp *) interp;

      /*
       * When we've got bytecode, this is the check for validity. That is,
       * the bytecode must be for the right interpreter (no cross-leaks!),
       * the code must be from the current epoch (so subcommand compilation
       * is up-to-date), the namespace must match (so variable handling
       * is right) and the resolverEpoch must match (so that new shadowed
       * commands and/or resolver changes are considered).
       */

      codePtr = procPtr->bodyPtr->internalRep.otherValuePtr;
      if (((Interp *) *codePtr->interpHandle != iPtr)
            || (codePtr->compileEpoch != iPtr->compileEpoch)
            || (codePtr->nsPtr != nsPtr)
            || (codePtr->nsEpoch != nsPtr->resolverEpoch)) {
          goto doCompilation;
      }
    } else {
    doCompilation:
      result = ProcCompileProc(interp, procPtr, procPtr->bodyPtr, nsPtr,
            (isLambda ? "body of lambda term" : "body of proc"),
            TclGetString(objv[isLambda]), &procPtr);
      if (result != TCL_OK) {
          return result;
      }
    }

    /*
     * Set up and push a new call frame for the new procedure invocation.
     * This call frame will execute in the proc's namespace, which might be
     * different than the current namespace. The proc's namespace is that of
     * its command, which can change if the command is renamed from one
     * namespace to another.
     */

    framePtrPtr = &framePtr;
    result = TclPushStackFrame(interp, (Tcl_CallFrame **) framePtrPtr,
          (Tcl_Namespace *) nsPtr,
          (isLambda? (FRAME_IS_PROC|FRAME_IS_LAMBDA) : FRAME_IS_PROC));
    if (result != TCL_OK) {
      return result;
    }

    framePtr->objc = objc;
    framePtr->objv = objv;
    framePtr->procPtr = procPtr;

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TclObjInterpProc --
 *
 *    When a Tcl procedure gets invoked during bytecode evaluation, this
 *    object-based routine gets invoked to interpret the procedure.
 *
 * Results:
 *    A standard Tcl object result value.
 *
 * Side effects:
 *    Depends on the commands in the procedure.
 *
 *----------------------------------------------------------------------
 */

int
TclObjInterpProc(
    ClientData clientData,    /* Record describing procedure to be
                         * interpreted. */
    register Tcl_Interp *interp,/* Interpreter in which procedure was
                         * invoked. */
    int objc,                 /* Count of number of arguments to this
                         * procedure. */
    Tcl_Obj *CONST objv[])    /* Argument value objects. */
{
    int result;

    result = PushProcCallFrame(clientData, interp, objc, objv, /*isLambda*/ 0);
    if (result == TCL_OK) {
      return TclObjInterpProcCore(interp, objv[0], 1, &MakeProcError);
    } else {
      return TCL_ERROR;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclObjInterpProcCore --
 *
 *    When a Tcl procedure, lambda term or anything else that works like a
 *    procedure gets invoked during bytecode evaluation, this object-based
 *    routine gets invoked to interpret the body.
 *
 * Results:
 *    A standard Tcl object result value.
 *
 * Side effects:
 *    Nearly anything; depends on the commands in the procedure body.
 *
 *----------------------------------------------------------------------
 */

int
TclObjInterpProcCore(
    register Tcl_Interp *interp,/* Interpreter in which procedure was
                         * invoked. */
    Tcl_Obj *procNameObj,     /* Procedure name for error reporting. */
    int skip,                 /* Number of initial arguments to be skipped,
                         * i.e., words in the "command name". */
    ProcErrorProc errorProc)  /* How to convert results from the script into
                         * results of the overall procedure. */
{
    Interp *iPtr = (Interp *) interp;
    register Proc *procPtr = iPtr->varFramePtr->procPtr;
    int result;
    CallFrame *freePtr;

    result = InitArgsAndLocals(interp, procNameObj, skip);
    if (result != TCL_OK) {
      goto procDone;
    }

#if defined(TCL_COMPILE_DEBUG)
    if (tclTraceExec >= 1) {
      register CallFrame *framePtr = iPtr->varFramePtr;
      register int i;

      if (framePtr->isProcCallFrame & FRAME_IS_LAMBDA) {
          fprintf(stdout, "Calling lambda ");
      } else {
          fprintf(stdout, "Calling proc ");
      }
      for (i = 0; i < framePtr->objc; i++) {
          TclPrintObject(stdout, framePtr->objv[i], 15);
          fprintf(stdout, " ");
      }
      fprintf(stdout, "\n");
      fflush(stdout);
    }
#endif /*TCL_COMPILE_DEBUG*/

    if (TCL_DTRACE_PROC_ARGS_ENABLED()) {
      char *a[10];
      int i = 0;
      int l = iPtr->varFramePtr->isProcCallFrame & FRAME_IS_LAMBDA ? 1 : 0;

      while (i < 10) {
          a[i] = (l < iPtr->varFramePtr->objc ? 
                TclGetString(iPtr->varFramePtr->objv[l]) : NULL); i++; l++;
      }
      TCL_DTRACE_PROC_ARGS(a[0], a[1], a[2], a[3], a[4], a[5], a[6], a[7],
            a[8], a[9]);
    }
    if (TCL_DTRACE_PROC_INFO_ENABLED() && iPtr->cmdFramePtr) {
      Tcl_Obj *info = TclInfoFrame(interp, iPtr->cmdFramePtr);
      char *a[4]; int i[2];
      
      TclDTraceInfo(info, a, i);
      TCL_DTRACE_PROC_INFO(a[0], a[1], a[2], a[3], i[0], i[1]);
      TclDecrRefCount(info);
    }

    /*
     * Invoke the commands in the procedure's body.
     */

    procPtr->refCount++;
    iPtr->numLevels++;

    if (TclInterpReady(interp) == TCL_ERROR) {
      result = TCL_ERROR;
    } else {
      register ByteCode *codePtr =
            procPtr->bodyPtr->internalRep.otherValuePtr;

      codePtr->refCount++;
      if (TCL_DTRACE_PROC_ENTRY_ENABLED()) {
          int l;
          
          l = iPtr->varFramePtr->isProcCallFrame & FRAME_IS_LAMBDA ? 2 : 1;
          TCL_DTRACE_PROC_ENTRY(TclGetString(procNameObj),
                iPtr->varFramePtr->objc - l,
                (Tcl_Obj **)(iPtr->varFramePtr->objv + l));
      }
      result = TclExecuteByteCode(interp, codePtr);
      if (TCL_DTRACE_PROC_RETURN_ENABLED()) {
          TCL_DTRACE_PROC_RETURN(TclGetString(procNameObj), result);
      }
      codePtr->refCount--;
      if (codePtr->refCount <= 0) {
          TclCleanupByteCode(codePtr);
      }
    }

    iPtr->numLevels--;
    procPtr->refCount--;
    if (procPtr->refCount <= 0) {
      TclProcCleanupProc(procPtr);
    }

    /*
     * Process the result code.
     */

    switch (result) {
    case TCL_RETURN:
      /*
       * If it is a 'return', do the TIP#90 processing now.
       */

      result = TclUpdateReturnInfo((Interp *) interp);
      break;

    case TCL_CONTINUE:
    case TCL_BREAK:
      /*
       * It's an error to get to this point from a 'break' or 'continue', so
       * transform to an error now.
       */

      Tcl_ResetResult(interp);
      Tcl_AppendResult(interp, "invoked \"",
            ((result == TCL_BREAK) ? "break" : "continue"),
            "\" outside of a loop", NULL);
      result = TCL_ERROR;

      /*
       * Fall through to the TCL_ERROR handling code.
       */

    case TCL_ERROR:
      /*
       * Now it _must_ be an error, so we need to log it as such. This means
       * filling out the error trace. Luckily, we just hand this off to the
       * function handed to us as an argument.
       */

      (*errorProc)(interp, procNameObj);

    default:
      /*
       * Process other results (OK and non-standard) by doing nothing
       * special, skipping directly to the code afterwards that cleans up
       * associated memory.
       *
       * Non-standard results are processed by passing them through quickly.
       * This means they all work as exceptions, unwinding the stack quickly
       * and neatly. Who knows how well they are handled by third-party code
       * though...
       */

      (void) 0;         /* do nothing */
    }

    if (TCL_DTRACE_PROC_RESULT_ENABLED()) {
      Tcl_Obj *r;

      r = Tcl_GetObjResult(interp);
      TCL_DTRACE_PROC_RESULT(TclGetString(procNameObj), result,
            TclGetString(r), r);
    }

  procDone:
    /*
     * Free the stack-allocated compiled locals and CallFrame. It is important
     * to pop the call frame without freeing it first: the compiledLocals
     * cannot be freed before the frame is popped, as the local variables must
     * be deleted. But the compiledLocals must be freed first, as they were
     * allocated later on the stack.
     */

    freePtr = iPtr->framePtr;
    Tcl_PopCallFrame(interp);       /* Pop but do not free. */
    TclStackFree(interp, freePtr->compiledLocals);
                              /* Free compiledLocals. */
    TclStackFree(interp, freePtr);  /* Free CallFrame. */
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * TclProcCompileProc --
 *
 *    Called just before a procedure is executed to compile the body to byte
 *    codes. If the type of the body is not "byte code" or if the compile
 *    conditions have changed (namespace context, epoch counters, etc.) then
 *    the body is recompiled. Otherwise, this function does nothing.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    May change the internal representation of the body object to compiled
 *    code.
 *
 *----------------------------------------------------------------------
 */

int
TclProcCompileProc(
    Tcl_Interp *interp,       /* Interpreter containing procedure. */
    Proc *procPtr,            /* Data associated with procedure. */
    Tcl_Obj *bodyPtr,         /* Body of proc. (Usually procPtr->bodyPtr,
                         * but could be any code fragment compiled in
                         * the context of this procedure.) */
    Namespace *nsPtr,         /* Namespace containing procedure. */
    CONST char *description,  /* string describing this body of code. */
    CONST char *procName)     /* Name of this procedure. */
{
    return ProcCompileProc(interp, procPtr, bodyPtr, nsPtr, description,
          procName, NULL);
}

static int
ProcCompileProc(
    Tcl_Interp *interp,       /* Interpreter containing procedure. */
    Proc *procPtr,            /* Data associated with procedure. */
    Tcl_Obj *bodyPtr,         /* Body of proc. (Usually procPtr->bodyPtr,
                         * but could be any code fragment compiled in
                         * the context of this procedure.) */
    Namespace *nsPtr,         /* Namespace containing procedure. */
    CONST char *description,  /* string describing this body of code. */
    CONST char *procName,     /* Name of this procedure. */
    Proc **procPtrPtr)        /* Points to storage where a replacement
                         * (Proc *) value may be written. */
{
    Interp *iPtr = (Interp *) interp;
    int i;
    Tcl_CallFrame *framePtr;
    Proc *saveProcPtr;
    ByteCode *codePtr = bodyPtr->internalRep.otherValuePtr;
    CompiledLocal *localPtr;

    /*
     * If necessary, compile the procedure's body. The compiler will allocate
     * frame slots for the procedure's non-argument local variables. If the
     * ByteCode already exists, make sure it hasn't been invalidated by
     * someone redefining a core command (this might make the compiled code
     * wrong). Also, if the code was compiled in/for a different interpreter,
     * we recompile it. Note that compiling the body might increase
     * procPtr->numCompiledLocals if new local variables are found while
     * compiling.
     *
     * Precompiled procedure bodies, however, are immutable and therefore they
     * are not recompiled, even if things have changed.
     */

    if (bodyPtr->typePtr == &tclByteCodeType) {
      if (((Interp *) *codePtr->interpHandle == iPtr)
            && (codePtr->compileEpoch == iPtr->compileEpoch)
            && (codePtr->nsPtr == nsPtr)
            && (codePtr->nsEpoch == nsPtr->resolverEpoch)) {
          return TCL_OK;
      } else {
          if (codePtr->flags & TCL_BYTECODE_PRECOMPILED) {
            if ((Interp *) *codePtr->interpHandle != iPtr) {
                Tcl_AppendResult(interp,
                      "a precompiled script jumped interps", NULL);
                return TCL_ERROR;
            }
            codePtr->compileEpoch = iPtr->compileEpoch;
            codePtr->nsPtr = nsPtr;
          } else {
            bodyPtr->typePtr->freeIntRepProc(bodyPtr);
            bodyPtr->typePtr = NULL;
          }
      }
    }
    if (bodyPtr->typePtr != &tclByteCodeType) {
      Tcl_HashEntry *hePtr;

#ifdef TCL_COMPILE_DEBUG
      if (tclTraceCompile >= 1) {
          /*
           * Display a line summarizing the top level command we are about
           * to compile.
           */

          Tcl_Obj *message;

          TclNewLiteralStringObj(message, "Compiling ");
          Tcl_IncrRefCount(message);
          Tcl_AppendStringsToObj(message, description, " \"", NULL);
          Tcl_AppendLimitedToObj(message, procName, -1, 50, NULL);
          fprintf(stdout, "%s\"\n", TclGetString(message));
          Tcl_DecrRefCount(message);
      }
#endif

      /*
       * Plug the current procPtr into the interpreter and coerce the code
       * body to byte codes. The interpreter needs to know which proc it's
       * compiling so that it can access its list of compiled locals.
       *
       * TRICKY NOTE: Be careful to push a call frame with the proper
       *   namespace context, so that the byte codes are compiled in the
       *   appropriate class context.
       */

      saveProcPtr = iPtr->compiledProcPtr;

      if (procPtrPtr != NULL && procPtr->refCount > 1) {
          Tcl_Command token;
          Tcl_CmdInfo info;
          Proc *newProc = (Proc *) ckalloc(sizeof(Proc));

          newProc->iPtr = procPtr->iPtr;
          newProc->refCount = 1;
          newProc->cmdPtr = procPtr->cmdPtr;
          token = (Tcl_Command) newProc->cmdPtr;
          newProc->bodyPtr = Tcl_DuplicateObj(bodyPtr);
          bodyPtr = newProc->bodyPtr;
          Tcl_IncrRefCount(bodyPtr);
          newProc->numArgs = procPtr->numArgs;

          newProc->numCompiledLocals = newProc->numArgs;
          newProc->firstLocalPtr = NULL;
          newProc->lastLocalPtr = NULL;
          localPtr = procPtr->firstLocalPtr;
          for (i=0; i<newProc->numArgs; i++, localPtr=localPtr->nextPtr) {
            CompiledLocal *copy = (CompiledLocal *) ckalloc((unsigned)
                  (sizeof(CompiledLocal) - sizeof(localPtr->name)
                  + localPtr->nameLength + 1));

            if (newProc->firstLocalPtr == NULL) {
                newProc->firstLocalPtr = newProc->lastLocalPtr = copy;
            } else {
                newProc->lastLocalPtr->nextPtr = copy;
                newProc->lastLocalPtr = copy;
            }
            copy->nextPtr = NULL;
            copy->nameLength = localPtr->nameLength;
            copy->frameIndex = localPtr->frameIndex;
            copy->flags = localPtr->flags;
            copy->defValuePtr = localPtr->defValuePtr;
            if (copy->defValuePtr) {
                Tcl_IncrRefCount(copy->defValuePtr);
            }
            copy->resolveInfo = localPtr->resolveInfo;
            strcpy(copy->name, localPtr->name);
          }

          /*
           * Reset the ClientData
           */

          Tcl_GetCommandInfoFromToken(token, &info);
          if (info.objClientData == (ClientData) procPtr) {
            info.objClientData = (ClientData) newProc;
          }
          if (info.clientData == (ClientData) procPtr) {
            info.clientData = (ClientData) newProc;
          }
          if (info.deleteData == (ClientData) procPtr) {
            info.deleteData = (ClientData) newProc;
          }
          Tcl_SetCommandInfoFromToken(token, &info);

          procPtr->refCount--;
          *procPtrPtr = procPtr = newProc;
      }
      iPtr->compiledProcPtr = procPtr;

      (void) TclPushStackFrame(interp, &framePtr,
            (Tcl_Namespace *) nsPtr, /* isProcCallFrame */ 0);

      /*
       * TIP #280: We get the invoking context from the cmdFrame which
       * was saved by 'Tcl_ProcObjCmd' (using linePBodyPtr).
       */

      hePtr = Tcl_FindHashEntry(iPtr->linePBodyPtr, (char *) procPtr);

      /*
       * Constructed saved frame has body as word 0. See Tcl_ProcObjCmd.
       */

      iPtr->invokeWord = 0;
      iPtr->invokeCmdFramePtr =
            (hePtr ? (CmdFrame *) Tcl_GetHashValue(hePtr) : NULL);
      (void) tclByteCodeType.setFromAnyProc(interp, bodyPtr);
      iPtr->invokeCmdFramePtr = NULL;
      TclPopStackFrame(interp);
      iPtr->compiledProcPtr = saveProcPtr;
    } else if (codePtr->nsEpoch != nsPtr->resolverEpoch) {
      /*
       * The resolver epoch has changed, but we only need to invalidate the
       * resolver cache.
       */

      codePtr->nsEpoch = nsPtr->resolverEpoch;
      codePtr->flags |= TCL_BYTECODE_RESOLVE_VARS;
    }
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * MakeProcError --
 *
 *    Function called by TclObjInterpProc to create the stack information
 *    upon an error from a procedure.
 *
 * Results:
 *    The interpreter's error info trace is set to a value that supplements
 *    the error code.
 *
 * Side effects:
 *    none.
 *
 *----------------------------------------------------------------------
 */

static void
MakeProcError(
    Tcl_Interp *interp,       /* The interpreter in which the procedure was
                         * called. */
    Tcl_Obj *procNameObj)     /* Name of the procedure. Used for error
                         * messages and trace information. */
{
    int overflow, limit = 60, nameLen;
    const char *procName = Tcl_GetStringFromObj(procNameObj, &nameLen);

    overflow = (nameLen > limit);
    Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
          "\n    (procedure \"%.*s%s\" line %d)",
          (overflow ? limit : nameLen), procName,
          (overflow ? "..." : ""), interp->errorLine));
}

/*
 *----------------------------------------------------------------------
 *
 * TclProcDeleteProc --
 *
 *    This function is invoked just before a command procedure is removed
 *    from an interpreter. Its job is to release all the resources allocated
 *    to the procedure.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    Memory gets freed, unless the procedure is actively being executed.
 *    In this case the cleanup is delayed until the last call to the current
 *    procedure completes.
 *
 *----------------------------------------------------------------------
 */

void
TclProcDeleteProc(
    ClientData clientData)    /* Procedure to be deleted. */
{
    Proc *procPtr = (Proc *) clientData;

    procPtr->refCount--;
    if (procPtr->refCount <= 0) {
      TclProcCleanupProc(procPtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclProcCleanupProc --
 *
 *    This function does all the real work of freeing up a Proc structure.
 *    It's called only when the structure's reference count becomes zero.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    Memory gets freed.
 *
 *----------------------------------------------------------------------
 */

void
TclProcCleanupProc(
    register Proc *procPtr)   /* Procedure to be deleted. */
{
    register CompiledLocal *localPtr;
    Tcl_Obj *bodyPtr = procPtr->bodyPtr;
    Tcl_Obj *defPtr;
    Tcl_ResolvedVarInfo *resVarInfo;
    Tcl_HashEntry *hePtr = NULL;
    CmdFrame *cfPtr = NULL;
    Interp *iPtr = procPtr->iPtr;

    if (bodyPtr != NULL) {
      Tcl_DecrRefCount(bodyPtr);
    }
    for (localPtr = procPtr->firstLocalPtr; localPtr != NULL; ) {
      CompiledLocal *nextPtr = localPtr->nextPtr;

      resVarInfo = localPtr->resolveInfo;
      if (resVarInfo) {
          if (resVarInfo->deleteProc) {
            (*resVarInfo->deleteProc)(resVarInfo);
          } else {
            ckfree((char *) resVarInfo);
          }
      }

      if (localPtr->defValuePtr != NULL) {
          defPtr = localPtr->defValuePtr;
          Tcl_DecrRefCount(defPtr);
      }
      ckfree((char *) localPtr);
      localPtr = nextPtr;
    }
    ckfree((char *) procPtr);

    /*
     * TIP #280: Release the location data associated with this Proc
     * structure, if any. The interpreter may not exist (For example for
     * procbody structurues created by tbcload.
     */

    if (!iPtr) {
      return;
    }

    hePtr = Tcl_FindHashEntry(iPtr->linePBodyPtr, (char *) procPtr);
    if (!hePtr) {
      return;
    }

    cfPtr = (CmdFrame *) Tcl_GetHashValue(hePtr);

    if (cfPtr->type == TCL_LOCATION_SOURCE) {
      Tcl_DecrRefCount(cfPtr->data.eval.path);
      cfPtr->data.eval.path = NULL;
    }
    ckfree((char *) cfPtr->line);
    cfPtr->line = NULL;
    ckfree((char *) cfPtr);
    Tcl_DeleteHashEntry(hePtr);
}

/*
 *----------------------------------------------------------------------
 *
 * TclUpdateReturnInfo --
 *
 *    This function is called when procedures return, and at other points
 *    where the TCL_RETURN code is used. It examines the returnLevel and
 *    returnCode to determine the real return status.
 *
 * Results:
 *    The return value is the true completion code to use for the procedure
 *    or script, instead of TCL_RETURN.
 *
 * Side effects:
 *    None.
 *
 *----------------------------------------------------------------------
 */

int
TclUpdateReturnInfo(
    Interp *iPtr)       /* Interpreter for which TCL_RETURN exception
                         * is being processed. */
{
    int code = TCL_RETURN;

    iPtr->returnLevel--;
    if (iPtr->returnLevel < 0) {
      Tcl_Panic("TclUpdateReturnInfo: negative return level");
    }
    if (iPtr->returnLevel == 0) {
      /*
       * Now we've reached the level to return the requested -code.
       */

      code = iPtr->returnCode;
      if (code == TCL_ERROR) {
          iPtr->flags |= ERR_LEGACY_COPY;
      }
    }
    return code;
}

/*
 *----------------------------------------------------------------------
 *
 * TclGetObjInterpProc --
 *
 *    Returns a pointer to the TclObjInterpProc function; this is different
 *    from the value obtained from the TclObjInterpProc reference on systems
 *    like Windows where import and export versions of a function exported
 *    by a DLL exist.
 *
 * Results:
 *    Returns the internal address of the TclObjInterpProc function.
 *
 * Side effects:
 *    None.
 *
 *----------------------------------------------------------------------
 */

TclObjCmdProcType
TclGetObjInterpProc(void)
{
    return (TclObjCmdProcType) TclObjInterpProc;
}

/*
 *----------------------------------------------------------------------
 *
 * TclNewProcBodyObj --
 *
 *    Creates a new object, of type "procbody", whose internal
 *    representation is the given Proc struct. The newly created object's
 *    reference count is 0.
 *
 * Results:
 *    Returns a pointer to a newly allocated Tcl_Obj, NULL on error.
 *
 * Side effects:
 *    The reference count in the ByteCode attached to the Proc is bumped up
 *    by one, since the internal rep stores a pointer to it.
 *
 *----------------------------------------------------------------------
 */

Tcl_Obj *
TclNewProcBodyObj(
    Proc *procPtr)            /* the Proc struct to store as the internal
                         * representation. */
{
    Tcl_Obj *objPtr;

    if (!procPtr) {
      return NULL;
    }

    TclNewObj(objPtr);
    if (objPtr) {
      objPtr->typePtr = &tclProcBodyType;
      objPtr->internalRep.otherValuePtr = procPtr;

      procPtr->refCount++;
    }

    return objPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * ProcBodyDup --
 *
 *    Tcl_ObjType's Dup function for the proc body object. Bumps the
 *    reference count on the Proc stored in the internal representation.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    Sets up the object in dupPtr to be a duplicate of the one in srcPtr.
 *
 *----------------------------------------------------------------------
 */

static void
ProcBodyDup(
    Tcl_Obj *srcPtr,          /* Object to copy. */
    Tcl_Obj *dupPtr)          /* Target object for the duplication. */
{
    Proc *procPtr = srcPtr->internalRep.otherValuePtr;

    dupPtr->typePtr = &tclProcBodyType;
    dupPtr->internalRep.otherValuePtr = procPtr;
    procPtr->refCount++;
}

/*
 *----------------------------------------------------------------------
 *
 * ProcBodyFree --
 *
 *    Tcl_ObjType's Free function for the proc body object. The reference
 *    count on its Proc struct is decreased by 1; if the count reaches 0,
 *    the proc is freed.
 *
 * Results:
 *    None.
 *
 * Side effects:
 *    If the reference count on the Proc struct reaches 0, the struct is
 *    freed.
 *
 *----------------------------------------------------------------------
 */

static void
ProcBodyFree(
    Tcl_Obj *objPtr)          /* The object to clean up. */
{
    Proc *procPtr = objPtr->internalRep.otherValuePtr;

    procPtr->refCount--;
    if (procPtr->refCount <= 0) {
      TclProcCleanupProc(procPtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * DupLambdaInternalRep, FreeLambdaInternalRep, SetLambdaFromAny --
 *
 *    How to manage the internal representations of lambda term objects.
 *    Syntactically they look like a two- or three-element list, where the
 *    first element is the formal arguments, the second is the the body, and
 *    the (optional) third is the namespace to execute the lambda term
 *    within (the global namespace is assumed if it is absent).
 *
 *----------------------------------------------------------------------
 */

static void
DupLambdaInternalRep(
    Tcl_Obj *srcPtr,          /* Object with internal rep to copy. */
    register Tcl_Obj *copyPtr)      /* Object with internal rep to set. */
{
    Proc *procPtr = srcPtr->internalRep.twoPtrValue.ptr1;
    Tcl_Obj *nsObjPtr = srcPtr->internalRep.twoPtrValue.ptr2;

    copyPtr->internalRep.twoPtrValue.ptr1 = procPtr;
    copyPtr->internalRep.twoPtrValue.ptr2 = nsObjPtr;

    procPtr->refCount++;
    Tcl_IncrRefCount(nsObjPtr);
    copyPtr->typePtr = &lambdaType;
}

static void
FreeLambdaInternalRep(
    register Tcl_Obj *objPtr) /* CmdName object with internal representation
                         * to free. */
{
    Proc *procPtr = objPtr->internalRep.twoPtrValue.ptr1;
    Tcl_Obj *nsObjPtr = objPtr->internalRep.twoPtrValue.ptr2;

    procPtr->refCount--;
    if (procPtr->refCount == 0) {
      TclProcCleanupProc(procPtr);
    }
    TclDecrRefCount(nsObjPtr);
}

static int
SetLambdaFromAny(
    Tcl_Interp *interp,       /* Used for error reporting if not NULL. */
    register Tcl_Obj *objPtr) /* The object to convert. */
{
    Interp *iPtr = (Interp *) interp;
    char *name;
    Tcl_Obj *argsPtr, *bodyPtr, *nsObjPtr, **objv, *errPtr;
    int objc, result;
    Proc *procPtr;

    /*
     * Convert objPtr to list type first; if it cannot be converted, or if its
     * length is not 2, then it cannot be converted to lambdaType.
     */

    result = TclListObjGetElements(interp, objPtr, &objc, &objv);
    if ((result != TCL_OK) || ((objc != 2) && (objc != 3))) {
      TclNewLiteralStringObj(errPtr, "can't interpret \"");
      Tcl_AppendObjToObj(errPtr, objPtr);
      Tcl_AppendToObj(errPtr, "\" as a lambda expression", -1);
      Tcl_SetObjResult(interp, errPtr);
      return TCL_ERROR;
    }

    argsPtr = objv[0];
    bodyPtr = objv[1];

    /*
     * Create and initialize the Proc struct. The cmdPtr field is set to NULL
     * to signal that this is an anonymous function.
     */

    name = TclGetString(objPtr);

    if (TclCreateProc(interp, /*ignored nsPtr*/ NULL, name, argsPtr, bodyPtr,
          &procPtr) != TCL_OK) {
      Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
            "\n    (parsing lambda expression \"%s\")", name));
      return TCL_ERROR;
    }

    /*
     * CAREFUL: TclCreateProc returns refCount==1! [Bug 1578454]
     * procPtr->refCount = 1;
     */

    procPtr->cmdPtr = NULL;

    /*
     * TIP #280: Remember the line the apply body is starting on. In a Byte
     * code context we ask the engine to provide us with the necessary
     * information. This is for the initialization of the byte code compiler
     * when the body is used for the first time.
     *
     * NOTE: The body is the second word in the 'objPtr'. Its location,
     * accessible through 'context.line[1]' (see below) is therefore only the
     * first approximation of the actual line the body is on. We have to use
     * the string rep of the 'objPtr' to determine the exact line. This is
     * available already through 'name'. Use 'TclListLines', see 'switch'
     * (tclCmdMZ.c).
     *
     * This code is nearly identical to the #280 code in Tcl_ProcObjCmd, see
     * this file. The differences are the different index of the body in the
     * line array of the context, and the special processing mentioned in the
     * previous paragraph to track into the list. Find a way to factor the
     * common elements into a single function.
     */

    if (iPtr->cmdFramePtr) {
      CmdFrame *contextPtr;

      contextPtr = (CmdFrame *) TclStackAlloc(interp, sizeof(CmdFrame));
      *contextPtr = *iPtr->cmdFramePtr;

      if (contextPtr->type == TCL_LOCATION_BC) {
          /*
           * Retrieve the source context from the bytecode. This call
           * accounts for the reference to the source file, if any, held in
           * 'context.data.eval.path'.
           */

          TclGetSrcInfoForPc(contextPtr);
      } else if (contextPtr->type == TCL_LOCATION_SOURCE) {
          /*
           * We created a new reference to the source file path name when we
           * created 'context' above. Account for the reference.
           */

          Tcl_IncrRefCount(contextPtr->data.eval.path);

      }

      if (contextPtr->type == TCL_LOCATION_SOURCE) {
          /*
           * We can record source location within a lambda only if the body
           * was not created by substitution.
           */

          if (contextPtr->line
                && (contextPtr->nline >= 2) && (contextPtr->line[1] >= 0)) {
            int isNew, buf[2];
            CmdFrame *cfPtr = (CmdFrame *) ckalloc(sizeof(CmdFrame));

            /*
             * Move from approximation (line of list cmd word) to actual
             * location (line of 2nd list element).
             */

            TclListLines(name, contextPtr->line[1], 2, buf);

            cfPtr->level = -1;
            cfPtr->type = contextPtr->type;
            cfPtr->line = (int *) ckalloc(sizeof(int));
            cfPtr->line[0] = buf[1];
            cfPtr->nline = 1;
            cfPtr->framePtr = NULL;
            cfPtr->nextPtr = NULL;

            cfPtr->data.eval.path = contextPtr->data.eval.path;
            Tcl_IncrRefCount(cfPtr->data.eval.path);

            cfPtr->cmd.str.cmd = NULL;
            cfPtr->cmd.str.len = 0;

            Tcl_SetHashValue(Tcl_CreateHashEntry(iPtr->linePBodyPtr,
                  (char *) procPtr, &isNew), cfPtr);
          }

          /*
           * 'contextPtr' is going out of scope. Release the reference that
           * it's holding to the source file path
           */

          Tcl_DecrRefCount(contextPtr->data.eval.path);
      }
      TclStackFree(interp, contextPtr);
    }

    /*
     * Set the namespace for this lambda: given by objv[2] understood as a
     * global reference, or else global per default.
     */

    if (objc == 2) {
      TclNewLiteralStringObj(nsObjPtr, "::");
    } else {
      char *nsName = TclGetString(objv[2]);

      if ((*nsName != ':') || (*(nsName+1) != ':')) {
          TclNewLiteralStringObj(nsObjPtr, "::");
          Tcl_AppendObjToObj(nsObjPtr, objv[2]);
      } else {
          nsObjPtr = objv[2];
      }
    }

    Tcl_IncrRefCount(nsObjPtr);

    /*
     * Free the list internalrep of objPtr - this will free argsPtr, but
     * bodyPtr retains a reference from the Proc structure. Then finish the
     * conversion to lambdaType.
     */

    objPtr->typePtr->freeIntRepProc(objPtr);

    objPtr->internalRep.twoPtrValue.ptr1 = procPtr;
    objPtr->internalRep.twoPtrValue.ptr2 = nsObjPtr;
    objPtr->typePtr = &lambdaType;
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ApplyObjCmd --
 *
 *    This object-based function is invoked to process the "apply" Tcl
 *    command. See the user documentation for details on what it does.
 *
 * Results:
 *    A standard Tcl object result value.
 *
 * Side effects:
 *    Depends on the content of the lambda term (i.e., objv[1]).
 *
 *----------------------------------------------------------------------
 */

int
Tcl_ApplyObjCmd(
    ClientData dummy,         /* Not used. */
    Tcl_Interp *interp,       /* Current interpreter. */
    int objc,                 /* Number of arguments. */
    Tcl_Obj *CONST objv[])    /* Argument objects. */
{
    Interp *iPtr = (Interp *) interp;
    Proc *procPtr = NULL;
    Tcl_Obj *lambdaPtr, *nsObjPtr;
    int result, isRootEnsemble;
    Command cmd;
    Tcl_Namespace *nsPtr;
    ExtraFrameInfo efi;

    if (objc < 2) {
      Tcl_WrongNumArgs(interp, 1, objv, "lambdaExpr ?arg1 arg2 ...?");
      return TCL_ERROR;
    }

    /*
     * Set lambdaPtr, convert it to lambdaType in the current interp if
     * necessary.
     */

    lambdaPtr = objv[1];
    if (lambdaPtr->typePtr == &lambdaType) {
      procPtr = lambdaPtr->internalRep.twoPtrValue.ptr1;
    }

#define JOE_EXTENSION 0
#if JOE_EXTENSION
    else {
      /*
       * Joe English's suggestion to allow cmdNames to function as lambdas.
       * Also requires making tclCmdNameType non-static in tclObj.c
       */

      Tcl_Obj *elemPtr;
      int numElem;

      if ((lambdaPtr->typePtr == &tclCmdNameType) ||
            (TclListObjGetElements(interp, lambdaPtr, &numElem,
            &elemPtr) == TCL_OK && numElem == 1)) {
          return Tcl_EvalObjv(interp, objc-1, objv+1, 0);
      }
    }
#endif

    if ((procPtr == NULL) || (procPtr->iPtr != iPtr)) {
      result = SetLambdaFromAny(interp, lambdaPtr);
      if (result != TCL_OK) {
          return result;
      }
      procPtr = lambdaPtr->internalRep.twoPtrValue.ptr1;
    }

    memset(&cmd, 0, sizeof(Command));
    procPtr->cmdPtr = &cmd;

    /*
     * TIP#280 (semi-)HACK!
     *
     * Using cmd.clientData to tell [info frame] how to render the
     * 'lambdaPtr'. The InfoFrameCmd will detect this case by testing cmd.hPtr
     * for NULL. This condition holds here because of the 'memset' above, and
     * nowhere else (in the core). Regular commands always have a valid
     * 'hPtr', and lambda's never.
     */

    efi.length = 1;
    efi.fields[0].name = "lambda";
    efi.fields[0].proc = NULL;
    efi.fields[0].clientData = lambdaPtr;
    cmd.clientData = &efi;

    /*
     * Find the namespace where this lambda should run, and push a call frame
     * for that namespace. Note that TclObjInterpProc() will pop it.
     */

    nsObjPtr = lambdaPtr->internalRep.twoPtrValue.ptr2;
    result = TclGetNamespaceFromObj(interp, nsObjPtr, &nsPtr);
    if (result != TCL_OK) {
      return result;
    }

    cmd.nsPtr = (Namespace *) nsPtr;

    isRootEnsemble = (iPtr->ensembleRewrite.sourceObjs == NULL);
    if (isRootEnsemble) {
      iPtr->ensembleRewrite.sourceObjs = objv;
      iPtr->ensembleRewrite.numRemovedObjs = 1;
      iPtr->ensembleRewrite.numInsertedObjs = 0;
    } else {
      iPtr->ensembleRewrite.numInsertedObjs -= 1;
    }

    result = PushProcCallFrame((ClientData) procPtr, interp, objc, objv, 1);
    if (result == TCL_OK) {
      result = TclObjInterpProcCore(interp, objv[1], 2, &MakeLambdaError);
    }

    if (isRootEnsemble) {
      iPtr->ensembleRewrite.sourceObjs = NULL;
      iPtr->ensembleRewrite.numRemovedObjs = 0;
      iPtr->ensembleRewrite.numInsertedObjs = 0;
    }

    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * MakeLambdaError --
 *
 *    Function called by TclObjInterpProc to create the stack information
 *    upon an error from a lambda term.
 *
 * Results:
 *    The interpreter's error info trace is set to a value that supplements
 *    the error code.
 *
 * Side effects:
 *    none.
 *
 *----------------------------------------------------------------------
 */

static void
MakeLambdaError(
    Tcl_Interp *interp,       /* The interpreter in which the procedure was
                         * called. */
    Tcl_Obj *procNameObj)     /* Name of the procedure. Used for error
                         * messages and trace information. */
{
    int overflow, limit = 60, nameLen;
    const char *procName = Tcl_GetStringFromObj(procNameObj, &nameLen);

    overflow = (nameLen > limit);
    Tcl_AppendObjToErrorInfo(interp, Tcl_ObjPrintf(
          "\n    (lambda term \"%.*s%s\" line %d)",
          (overflow ? limit : nameLen), procName,
          (overflow ? "..." : ""), interp->errorLine));
}


/*
 *----------------------------------------------------------------------
 *
 * Tcl_DisassembleObjCmd --
 *
 *    Implementation of the "::tcl::unsupported::disassemble" command. This
 *    command is not documented, but will disassemble procedures, lambda
 *    terms and general scripts. Note that will compile terms if necessary
 *    in order to disassemble them.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_DisassembleObjCmd(
    ClientData dummy,         /* Not used. */
    Tcl_Interp *interp,       /* Current interpreter. */
    int objc,                 /* Number of arguments. */
    Tcl_Obj *CONST objv[])    /* Argument objects. */
{
    static const char *types[] = {
      "lambda", "proc", "script", NULL
    };
    enum Types {
      DISAS_LAMBDA, DISAS_PROC, DISAS_SCRIPT
    };
    int idx, result;

    if (objc != 3) {
      Tcl_WrongNumArgs(interp, 1, objv, "type procName|lambdaTerm|script");
      return TCL_ERROR;
    }
    if (Tcl_GetIndexFromObj(interp, objv[1], types, "type", 0, &idx)!=TCL_OK){
      return TCL_ERROR;
    }

    switch ((enum Types) idx) {
    case DISAS_LAMBDA: {
      Proc *procPtr = NULL;
      Command cmd;
      Tcl_Obj *nsObjPtr;
      Tcl_Namespace *nsPtr;

      /*
       * Compile (if uncompiled) and disassemble a lambda term.
       */

      if (objv[2]->typePtr == &lambdaType) {
          procPtr = objv[2]->internalRep.twoPtrValue.ptr1;
      }
      if (procPtr == NULL || procPtr->iPtr != (Interp *) interp) {
          result = SetLambdaFromAny(interp, objv[2]);
          if (result != TCL_OK) {
            return result;
          }
          procPtr = objv[2]->internalRep.twoPtrValue.ptr1;
      }

      memset(&cmd, 0, sizeof(Command));
      nsObjPtr = objv[2]->internalRep.twoPtrValue.ptr2;
      result = TclGetNamespaceFromObj(interp, nsObjPtr, &nsPtr);
      if (result != TCL_OK) {
          return result;
      }
      cmd.nsPtr = (Namespace *) nsPtr;
      procPtr->cmdPtr = &cmd;
      result = PushProcCallFrame(procPtr, interp, objc, objv, 1);
      if (result != TCL_OK) {
          return result;
      }
      TclPopStackFrame(interp);
      if (((ByteCode *) procPtr->bodyPtr->internalRep.otherValuePtr)->flags
            & TCL_BYTECODE_PRECOMPILED) {
          Tcl_AppendResult(interp, "may not disassemble prebuilt bytecode",
                NULL);
          return TCL_ERROR;
      }
      Tcl_SetObjResult(interp, TclDisassembleByteCodeObj(procPtr->bodyPtr));
      break;
    }
    case DISAS_PROC: {
      Proc *procPtr = TclFindProc((Interp *) interp, TclGetString(objv[2]));

      if (procPtr == NULL) {
          Tcl_AppendResult(interp, "\"", TclGetString(objv[2]),
                "\" isn't a procedure", NULL);
          return TCL_ERROR;
      }

      /*
       * Compile (if uncompiled) and disassemble a procedure.
       */

      result = PushProcCallFrame(procPtr, interp, 2, objv+1, 1);
      if (result != TCL_OK) {
          return result;
      }
      TclPopStackFrame(interp);
      if (((ByteCode *) procPtr->bodyPtr->internalRep.otherValuePtr)->flags
            & TCL_BYTECODE_PRECOMPILED) {
          Tcl_AppendResult(interp, "may not disassemble prebuilt bytecode",
                NULL);
          return TCL_ERROR;
      }
      Tcl_SetObjResult(interp, TclDisassembleByteCodeObj(procPtr->bodyPtr));
      break;
    }
    case DISAS_SCRIPT:
      /*
       * Compile and disassemble a script.
       */

      if (objv[2]->typePtr != &tclByteCodeType) {
          if (TclSetByteCodeFromAny(interp, objv[2], NULL, NULL) != TCL_OK){
            return TCL_ERROR;
          }
      }
      Tcl_SetObjResult(interp, TclDisassembleByteCodeObj(objv[2]));
      break;
    }
    return TCL_OK;
}

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */

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