shared_source/c_tcl_base_7_5_w_mods/tclresolve.c

/* $Header$ */
/*
 * tclResolve.c --
 *
 *      Contains hooks for customized command/variable name resolution
 *      schemes.  These hooks allow extensions like [incr Tcl] to add
 *      their own name resolution rules to the Tcl language.  Rules can
 *      be applied to a particular namespace, to the interpreter as a
 *      whole, or both.
 *
 * Copyright (c) 1998 Lucent Technologies, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclresolve.c,v 1.1.1.1 2001/06/13 04:45:45 dtashley Exp $
 */

#include "tclInt.h"

/*
 * Declarations for procedures local to this file:
 */

static void             BumpCmdRefEpochs _ANSI_ARGS_((Namespace *nsPtr));


/*
 *----------------------------------------------------------------------
 *
 * Tcl_AddInterpResolvers --
 *
 *      Adds a set of command/variable resolution procedures to an
 *      interpreter.  These procedures are consulted when commands
 *      are resolved in Tcl_FindCommand, and when variables are
 *      resolved in TclLookupVar and LookupCompiledLocal.  Each
 *      namespace may also have its own set of resolution procedures
 *      which take precedence over those for the interpreter.
 *
 *      When a name is resolved, it is handled as follows.  First,
 *      the name is passed to the resolution procedures for the
 *      namespace.  If not resolved, the name is passed to each of
 *      the resolution procedures added to the interpreter.  Finally,
 *      if still not resolved, the name is handled using the default
 *      Tcl rules for name resolution.
 *
 * Results:
 *      Returns pointers to the current name resolution procedures
 *      in the cmdProcPtr, varProcPtr and compiledVarProcPtr
 *      arguments.
 *
 * Side effects:
 *      If a compiledVarProc is specified, this procedure bumps the
 *      compileEpoch for the interpreter, forcing all code to be
 *      recompiled.  If a cmdProc is specified, this procedure bumps
 *      the cmdRefEpoch in all namespaces, forcing commands to be
 *      resolved again using the new rules.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_AddInterpResolvers(interp, name, cmdProc, varProc, compiledVarProc)

    Tcl_Interp *interp;                 /* Interpreter whose name resolution
                                         * rules are being modified. */
    char *name;                         /* Name of this resolution scheme. */
    Tcl_ResolveCmdProc *cmdProc;        /* New procedure for command
                                         * resolution */
    Tcl_ResolveVarProc *varProc;        /* Procedure for variable resolution
                                         * at runtime */
    Tcl_ResolveCompiledVarProc *compiledVarProc;
                                        /* Procedure for variable resolution
                                         * at compile time. */
{
    Interp *iPtr = (Interp*)interp;
    ResolverScheme *resPtr;

    /*
     *  Since we're adding a new name resolution scheme, we must force
     *  all code to be recompiled to use the new scheme.  If there
     *  are new compiled variable resolution rules, bump the compiler
     *  epoch to invalidate compiled code.  If there are new command
     *  resolution rules, bump the cmdRefEpoch in all namespaces.
     */
    if (compiledVarProc) {
        iPtr->compileEpoch++;
    }
    if (cmdProc) {
        BumpCmdRefEpochs(iPtr->globalNsPtr);
    }

    /*
     *  Look for an existing scheme with the given name.  If found,
     *  then replace its rules.
     */
    for (resPtr = iPtr->resolverPtr; resPtr != NULL; resPtr = resPtr->nextPtr) {
        if (*name == *resPtr->name && strcmp(name, resPtr->name) == 0) {
            resPtr->cmdResProc = cmdProc;
            resPtr->varResProc = varProc;
            resPtr->compiledVarResProc = compiledVarProc;
            return;
        }
    }

    /*
     *  Otherwise, this is a new scheme.  Add it to the FRONT
     *  of the linked list, so that it overrides existing schemes.
     */
    resPtr = (ResolverScheme *) ckalloc(sizeof(ResolverScheme));
    resPtr->name = (char*)ckalloc((unsigned)(strlen(name)+1));
    strcpy(resPtr->name, name);
    resPtr->cmdResProc = cmdProc;
    resPtr->varResProc = varProc;
    resPtr->compiledVarResProc = compiledVarProc;
    resPtr->nextPtr = iPtr->resolverPtr;
    iPtr->resolverPtr = resPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetInterpResolvers --
 *
 *      Looks for a set of command/variable resolution procedures with
 *      the given name in an interpreter.  These procedures are
 *      registered by calling Tcl_AddInterpResolvers.
 *
 * Results:
 *      If the name is recognized, this procedure returns non-zero,
 *      along with pointers to the name resolution procedures in
 *      the Tcl_ResolverInfo structure.  If the name is not recognized,
 *      this procedure returns zero.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_GetInterpResolvers(interp, name, resInfoPtr)

    Tcl_Interp *interp;                 /* Interpreter whose name resolution
                                         * rules are being queried. */
    char *name;                         /* Look for a scheme with this name. */
    Tcl_ResolverInfo *resInfoPtr;       /* Returns pointers to the procedures,
                                         * if found */
{
    Interp *iPtr = (Interp*)interp;
    ResolverScheme *resPtr;

    /*
     *  Look for an existing scheme with the given name.  If found,
     *  then return pointers to its procedures.
     */
    for (resPtr = iPtr->resolverPtr; resPtr != NULL; resPtr = resPtr->nextPtr) {
        if (*name == *resPtr->name && strcmp(name, resPtr->name) == 0) {
            resInfoPtr->cmdResProc = resPtr->cmdResProc;
            resInfoPtr->varResProc = resPtr->varResProc;
            resInfoPtr->compiledVarResProc = resPtr->compiledVarResProc;
            return 1;
        }
    }

    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_RemoveInterpResolvers --
 *
 *      Removes a set of command/variable resolution procedures
 *      previously added by Tcl_AddInterpResolvers.  The next time
 *      a command/variable name is resolved, these procedures
 *      won't be consulted.
 *
 * Results:
 *      Returns non-zero if the name was recognized and the
 *      resolution scheme was deleted.  Returns zero otherwise.
 *
 * Side effects:
 *      If a scheme with a compiledVarProc was deleted, this procedure
 *      bumps the compileEpoch for the interpreter, forcing all code
 *      to be recompiled.  If a scheme with a cmdProc was deleted,
 *      this procedure bumps the cmdRefEpoch in all namespaces,
 *      forcing commands to be resolved again using the new rules.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_RemoveInterpResolvers(interp, name)

    Tcl_Interp *interp;                 /* Interpreter whose name resolution
                                         * rules are being modified. */
    char *name;                         /* Name of the scheme to be removed. */
{
    Interp *iPtr = (Interp*)interp;
    ResolverScheme **prevPtrPtr, *resPtr;

    /*
     *  Look for an existing scheme with the given name.
     */
    prevPtrPtr = &iPtr->resolverPtr;
    for (resPtr = iPtr->resolverPtr; resPtr != NULL; resPtr = resPtr->nextPtr) {
        if (*name == *resPtr->name && strcmp(name, resPtr->name) == 0) {
            break;
        }
        prevPtrPtr = &resPtr->nextPtr;
    }

    /*
     *  If we found the scheme, delete it.
     */
    if (resPtr) {
        /*
         *  If we're deleting a scheme with compiled variable resolution
         *  rules, bump the compiler epoch to invalidate compiled code.
         *  If we're deleting a scheme with command resolution rules,
         *  bump the cmdRefEpoch in all namespaces.
         */
        if (resPtr->compiledVarResProc) {
            iPtr->compileEpoch++;
        }
        if (resPtr->cmdResProc) {
            BumpCmdRefEpochs(iPtr->globalNsPtr);
        }

        *prevPtrPtr = resPtr->nextPtr;
        ckfree(resPtr->name);
        ckfree((char *) resPtr);

        return 1;
    }
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * BumpCmdRefEpochs --
 *
 *      This procedure is used to bump the cmdRefEpoch counters in
 *      the specified namespace and all of its child namespaces.
 *      It is used whenever name resolution schemes are added/removed
 *      from an interpreter, to invalidate all command references.
 *
 * Results:
 *      None.
 *
 * Side effects:
 *      Bumps the cmdRefEpoch in the specified namespace and its
 *      children, recursively.
 *
 *----------------------------------------------------------------------
 */

static void
BumpCmdRefEpochs(nsPtr)
    Namespace *nsPtr;                   /* Namespace being modified. */
{
    Tcl_HashEntry *entry;
    Tcl_HashSearch search;
    Namespace *childNsPtr;

    nsPtr->cmdRefEpoch++;

    for (entry = Tcl_FirstHashEntry(&nsPtr->childTable, &search);
            entry != NULL;
            entry = Tcl_NextHashEntry(&search)) {

        childNsPtr = (Namespace *) Tcl_GetHashValue(entry);
        BumpCmdRefEpochs(childNsPtr);
    }
}


/*
 *----------------------------------------------------------------------
 *
 * Tcl_SetNamespaceResolvers --
 *
 *      Sets the command/variable resolution procedures for a namespace,
 *      thereby changing the way that command/variable names are
 *      interpreted.  This allows extension writers to support different
 *      name resolution schemes, such as those for object-oriented
 *      packages.
 *
 *      Command resolution is handled by a procedure of the following
 *      type:
 *
 *        typedef int (Tcl_ResolveCmdProc) _ANSI_ARGS_((
 *              Tcl_Interp* interp, char* name, Tcl_Namespace *context,
 *              int flags, Tcl_Command *rPtr));
 *          
 *      Whenever a command is executed or Tcl_FindCommand is invoked
 *      within the namespace, this procedure is called to resolve the
 *      command name.  If this procedure is able to resolve the name,
 *      it should return the status code TCL_OK, along with the
 *      corresponding Tcl_Command in the rPtr argument.  Otherwise,
 *      the procedure can return TCL_CONTINUE, and the command will
 *      be treated under the usual name resolution rules.  Or, it can
 *      return TCL_ERROR, and the command will be considered invalid.
 *
 *      Variable resolution is handled by two procedures.  The first
 *      is called whenever a variable needs to be resolved at compile
 *      time:
 *
 *        typedef int (Tcl_ResolveCompiledVarProc) _ANSI_ARGS_((
 *              Tcl_Interp* interp, char* name, Tcl_Namespace *context,
 *              Tcl_ResolvedVarInfo *rPtr));
 *
 *      If this procedure is able to resolve the name, it should return
 *      the status code TCL_OK, along with variable resolution info in
 *      the rPtr argument; this info will be used to set up compiled
 *      locals in the call frame at runtime.  The procedure may also
 *      return TCL_CONTINUE, and the variable will be treated under
 *      the usual name resolution rules.  Or, it can return TCL_ERROR,
 *      and the variable will be considered invalid.
 *
 *      Another procedure is used whenever a variable needs to be
 *      resolved at runtime but it is not recognized as a compiled local.
 *      (For example, the variable may be requested via
 *      Tcl_FindNamespaceVar.) This procedure has the following type:
 *
 *        typedef int (Tcl_ResolveVarProc) _ANSI_ARGS_((
 *              Tcl_Interp* interp, char* name, Tcl_Namespace *context,
 *              int flags, Tcl_Var *rPtr));
 *
 *      This procedure is quite similar to the compile-time version.
 *      It returns the same status codes, but if variable resolution
 *      succeeds, this procedure returns a Tcl_Var directly via the
 *      rPtr argument.
 *
 * Results:
 *      Nothing.
 *
 * Side effects:
 *      Bumps the command epoch counter for the namespace, invalidating
 *      all command references in that namespace.  Also bumps the
 *      resolver epoch counter for the namespace, forcing all code
 *      in the namespace to be recompiled.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_SetNamespaceResolvers(namespacePtr, cmdProc, varProc, compiledVarProc)
    Tcl_Namespace *namespacePtr;        /* Namespace whose resolution rules
                                         * are being modified. */
    Tcl_ResolveCmdProc *cmdProc;        /* Procedure for command resolution */
    Tcl_ResolveVarProc *varProc;        /* Procedure for variable resolution
                                         * at runtime */
    Tcl_ResolveCompiledVarProc *compiledVarProc;
                                        /* Procedure for variable resolution
                                         * at compile time. */
{
    Namespace *nsPtr = (Namespace*)namespacePtr;

    /*
     *  Plug in the new command resolver, and bump the epoch counters
     *  so that all code will have to be recompiled and all commands
     *  will have to be resolved again using the new policy.
     */
    nsPtr->cmdResProc = cmdProc;
    nsPtr->varResProc = varProc;
    nsPtr->compiledVarResProc = compiledVarProc;

    nsPtr->cmdRefEpoch++;
    nsPtr->resolverEpoch++;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetNamespaceResolvers --
 *
 *      Returns the current command/variable resolution procedures
 *      for a namespace.  By default, these procedures are NULL.
 *      New procedures can be installed by calling
 *      Tcl_SetNamespaceResolvers, to provide new name resolution
 *      rules.
 *
 * Results:
 *      Returns non-zero if any name resolution procedures have been
 *      assigned to this namespace; also returns pointers to the
 *      procedures in the Tcl_ResolverInfo structure.  Returns zero
 *      otherwise.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_GetNamespaceResolvers(namespacePtr, resInfoPtr)

    Tcl_Namespace *namespacePtr;        /* Namespace whose resolution rules
                                         * are being modified. */
    Tcl_ResolverInfo *resInfoPtr;       /* Returns: pointers for all
                                         * name resolution procedures
                                         * assigned to this namespace. */
{
    Namespace *nsPtr = (Namespace*)namespacePtr;

    resInfoPtr->cmdResProc = nsPtr->cmdResProc;
    resInfoPtr->varResProc = nsPtr->varResProc;
    resInfoPtr->compiledVarResProc = nsPtr->compiledVarResProc;

    if (nsPtr->cmdResProc != NULL ||
        nsPtr->varResProc != NULL ||
        nsPtr->compiledVarResProc != NULL) {
        return 1;
    }
    return 0;
}

/* End of tclresolve.c */
1	dashley	71	/* $Header$ */
2			/*
3			* tclResolve.c --
4			*
5			* Contains hooks for customized command/variable name resolution
6			* schemes. These hooks allow extensions like [incr Tcl] to add
7			* their own name resolution rules to the Tcl language. Rules can
8			* be applied to a particular namespace, to the interpreter as a
9			* whole, or both.
10			*
11			* Copyright (c) 1998 Lucent Technologies, Inc.
12			*
13			* See the file "license.terms" for information on usage and redistribution
14			* of this file, and for a DISCLAIMER OF ALL WARRANTIES.
15			*
16			* RCS: @(#) $Id: tclresolve.c,v 1.1.1.1 2001/06/13 04:45:45 dtashley Exp $
17			*/
18
19			#include "tclInt.h"
20
21			/*
22			* Declarations for procedures local to this file:
23			*/
24
25			static void BumpCmdRefEpochs _ANSI_ARGS_((Namespace *nsPtr));
26
27
28			/*
29			*----------------------------------------------------------------------
30			*
31			* Tcl_AddInterpResolvers --
32			*
33			* Adds a set of command/variable resolution procedures to an
34			* interpreter. These procedures are consulted when commands
35			* are resolved in Tcl_FindCommand, and when variables are
36			* resolved in TclLookupVar and LookupCompiledLocal. Each
37			* namespace may also have its own set of resolution procedures
38			* which take precedence over those for the interpreter.
39			*
40			* When a name is resolved, it is handled as follows. First,
41			* the name is passed to the resolution procedures for the
42			* namespace. If not resolved, the name is passed to each of
43			* the resolution procedures added to the interpreter. Finally,
44			* if still not resolved, the name is handled using the default
45			* Tcl rules for name resolution.
46			*
47			* Results:
48			* Returns pointers to the current name resolution procedures
49			* in the cmdProcPtr, varProcPtr and compiledVarProcPtr
50			* arguments.
51			*
52			* Side effects:
53			* If a compiledVarProc is specified, this procedure bumps the
54			* compileEpoch for the interpreter, forcing all code to be
55			* recompiled. If a cmdProc is specified, this procedure bumps
56			* the cmdRefEpoch in all namespaces, forcing commands to be
57			* resolved again using the new rules.
58			*
59			*----------------------------------------------------------------------
60			*/
61
62			void
63			Tcl_AddInterpResolvers(interp, name, cmdProc, varProc, compiledVarProc)
64
65			Tcl_Interp interp; / Interpreter whose name resolution
66			* rules are being modified. */
67			char name; / Name of this resolution scheme. */
68			Tcl_ResolveCmdProc cmdProc; / New procedure for command
69			* resolution */
70			Tcl_ResolveVarProc varProc; / Procedure for variable resolution
71			* at runtime */
72			Tcl_ResolveCompiledVarProc *compiledVarProc;
73			/* Procedure for variable resolution
74			* at compile time. */
75			{
76			Interp iPtr = (Interp)interp;
77			ResolverScheme *resPtr;
78
79			/*
80			* Since we're adding a new name resolution scheme, we must force
81			* all code to be recompiled to use the new scheme. If there
82			* are new compiled variable resolution rules, bump the compiler
83			* epoch to invalidate compiled code. If there are new command
84			* resolution rules, bump the cmdRefEpoch in all namespaces.
85			*/
86			if (compiledVarProc) {
87			iPtr->compileEpoch++;
88			}
89			if (cmdProc) {
90			BumpCmdRefEpochs(iPtr->globalNsPtr);
91			}
92
93			/*
94			* Look for an existing scheme with the given name. If found,
95			* then replace its rules.
96			*/
97			for (resPtr = iPtr->resolverPtr; resPtr != NULL; resPtr = resPtr->nextPtr) {
98			if (name == resPtr->name && strcmp(name, resPtr->name) == 0) {
99			resPtr->cmdResProc = cmdProc;
100			resPtr->varResProc = varProc;
101			resPtr->compiledVarResProc = compiledVarProc;
102			return;
103			}
104			}
105
106			/*
107			* Otherwise, this is a new scheme. Add it to the FRONT
108			* of the linked list, so that it overrides existing schemes.
109			*/
110			resPtr = (ResolverScheme *) ckalloc(sizeof(ResolverScheme));
111			resPtr->name = (char*)ckalloc((unsigned)(strlen(name)+1));
112			strcpy(resPtr->name, name);
113			resPtr->cmdResProc = cmdProc;
114			resPtr->varResProc = varProc;
115			resPtr->compiledVarResProc = compiledVarProc;
116			resPtr->nextPtr = iPtr->resolverPtr;
117			iPtr->resolverPtr = resPtr;
118			}
119
120			/*
121			*----------------------------------------------------------------------
122			*
123			* Tcl_GetInterpResolvers --
124			*
125			* Looks for a set of command/variable resolution procedures with
126			* the given name in an interpreter. These procedures are
127			* registered by calling Tcl_AddInterpResolvers.
128			*
129			* Results:
130			* If the name is recognized, this procedure returns non-zero,
131			* along with pointers to the name resolution procedures in
132			* the Tcl_ResolverInfo structure. If the name is not recognized,
133			* this procedure returns zero.
134			*
135			* Side effects:
136			* None.
137			*
138			*----------------------------------------------------------------------
139			*/
140
141			int
142			Tcl_GetInterpResolvers(interp, name, resInfoPtr)
143
144			Tcl_Interp interp; / Interpreter whose name resolution
145			* rules are being queried. */
146			char name; / Look for a scheme with this name. */
147			Tcl_ResolverInfo resInfoPtr; / Returns pointers to the procedures,
148			* if found */
149			{
150			Interp iPtr = (Interp)interp;
151			ResolverScheme *resPtr;
152
153			/*
154			* Look for an existing scheme with the given name. If found,
155			* then return pointers to its procedures.
156			*/
157			for (resPtr = iPtr->resolverPtr; resPtr != NULL; resPtr = resPtr->nextPtr) {
158			if (name == resPtr->name && strcmp(name, resPtr->name) == 0) {
159			resInfoPtr->cmdResProc = resPtr->cmdResProc;
160			resInfoPtr->varResProc = resPtr->varResProc;
161			resInfoPtr->compiledVarResProc = resPtr->compiledVarResProc;
162			return 1;
163			}
164			}
165
166			return 0;
167			}
168
169			/*
170			*----------------------------------------------------------------------
171			*
172			* Tcl_RemoveInterpResolvers --
173			*
174			* Removes a set of command/variable resolution procedures
175			* previously added by Tcl_AddInterpResolvers. The next time
176			* a command/variable name is resolved, these procedures
177			* won't be consulted.
178			*
179			* Results:
180			* Returns non-zero if the name was recognized and the
181			* resolution scheme was deleted. Returns zero otherwise.
182			*
183			* Side effects:
184			* If a scheme with a compiledVarProc was deleted, this procedure
185			* bumps the compileEpoch for the interpreter, forcing all code
186			* to be recompiled. If a scheme with a cmdProc was deleted,
187			* this procedure bumps the cmdRefEpoch in all namespaces,
188			* forcing commands to be resolved again using the new rules.
189			*
190			*----------------------------------------------------------------------
191			*/
192
193			int
194			Tcl_RemoveInterpResolvers(interp, name)
195
196			Tcl_Interp interp; / Interpreter whose name resolution
197			* rules are being modified. */
198			char name; / Name of the scheme to be removed. */
199			{
200			Interp iPtr = (Interp)interp;
201			ResolverScheme *prevPtrPtr, resPtr;
202
203			/*
204			* Look for an existing scheme with the given name.
205			*/
206			prevPtrPtr = &iPtr->resolverPtr;
207			for (resPtr = iPtr->resolverPtr; resPtr != NULL; resPtr = resPtr->nextPtr) {
208			if (name == resPtr->name && strcmp(name, resPtr->name) == 0) {
209			break;
210			}
211			prevPtrPtr = &resPtr->nextPtr;
212			}
213
214			/*
215			* If we found the scheme, delete it.
216			*/
217			if (resPtr) {
218			/*
219			* If we're deleting a scheme with compiled variable resolution
220			* rules, bump the compiler epoch to invalidate compiled code.
221			* If we're deleting a scheme with command resolution rules,
222			* bump the cmdRefEpoch in all namespaces.
223			*/
224			if (resPtr->compiledVarResProc) {
225			iPtr->compileEpoch++;
226			}
227			if (resPtr->cmdResProc) {
228			BumpCmdRefEpochs(iPtr->globalNsPtr);
229			}
230
231			*prevPtrPtr = resPtr->nextPtr;
232			ckfree(resPtr->name);
233			ckfree((char *) resPtr);
234
235			return 1;
236			}
237			return 0;
238			}
239
240			/*
241			*----------------------------------------------------------------------
242			*
243			* BumpCmdRefEpochs --
244			*
245			* This procedure is used to bump the cmdRefEpoch counters in
246			* the specified namespace and all of its child namespaces.
247			* It is used whenever name resolution schemes are added/removed
248			* from an interpreter, to invalidate all command references.
249			*
250			* Results:
251			* None.
252			*
253			* Side effects:
254			* Bumps the cmdRefEpoch in the specified namespace and its
255			* children, recursively.
256			*
257			*----------------------------------------------------------------------
258			*/
259
260			static void
261			BumpCmdRefEpochs(nsPtr)
262			Namespace nsPtr; / Namespace being modified. */
263			{
264			Tcl_HashEntry *entry;
265			Tcl_HashSearch search;
266			Namespace *childNsPtr;
267
268			nsPtr->cmdRefEpoch++;
269
270			for (entry = Tcl_FirstHashEntry(&nsPtr->childTable, &search);
271			entry != NULL;
272			entry = Tcl_NextHashEntry(&search)) {
273
274			childNsPtr = (Namespace *) Tcl_GetHashValue(entry);
275			BumpCmdRefEpochs(childNsPtr);
276			}
277			}
278
279
280			/*
281			*----------------------------------------------------------------------
282			*
283			* Tcl_SetNamespaceResolvers --
284			*
285			* Sets the command/variable resolution procedures for a namespace,
286			* thereby changing the way that command/variable names are
287			* interpreted. This allows extension writers to support different
288			* name resolution schemes, such as those for object-oriented
289			* packages.
290			*
291			* Command resolution is handled by a procedure of the following
292			* type:
293			*
294			* typedef int (Tcl_ResolveCmdProc) _ANSI_ARGS_((
295			* Tcl_Interp* interp, char* name, Tcl_Namespace *context,
296			* int flags, Tcl_Command *rPtr));
297			*
298			* Whenever a command is executed or Tcl_FindCommand is invoked
299			* within the namespace, this procedure is called to resolve the
300			* command name. If this procedure is able to resolve the name,
301			* it should return the status code TCL_OK, along with the
302			* corresponding Tcl_Command in the rPtr argument. Otherwise,
303			* the procedure can return TCL_CONTINUE, and the command will
304			* be treated under the usual name resolution rules. Or, it can
305			* return TCL_ERROR, and the command will be considered invalid.
306			*
307			* Variable resolution is handled by two procedures. The first
308			* is called whenever a variable needs to be resolved at compile
309			* time:
310			*
311			* typedef int (Tcl_ResolveCompiledVarProc) _ANSI_ARGS_((
312			* Tcl_Interp* interp, char* name, Tcl_Namespace *context,
313			* Tcl_ResolvedVarInfo *rPtr));
314			*
315			* If this procedure is able to resolve the name, it should return
316			* the status code TCL_OK, along with variable resolution info in
317			* the rPtr argument; this info will be used to set up compiled
318			* locals in the call frame at runtime. The procedure may also
319			* return TCL_CONTINUE, and the variable will be treated under
320			* the usual name resolution rules. Or, it can return TCL_ERROR,
321			* and the variable will be considered invalid.
322			*
323			* Another procedure is used whenever a variable needs to be
324			* resolved at runtime but it is not recognized as a compiled local.
325			* (For example, the variable may be requested via
326			* Tcl_FindNamespaceVar.) This procedure has the following type:
327			*
328			* typedef int (Tcl_ResolveVarProc) _ANSI_ARGS_((
329			* Tcl_Interp* interp, char* name, Tcl_Namespace *context,
330			* int flags, Tcl_Var *rPtr));
331			*
332			* This procedure is quite similar to the compile-time version.
333			* It returns the same status codes, but if variable resolution
334			* succeeds, this procedure returns a Tcl_Var directly via the
335			* rPtr argument.
336			*
337			* Results:
338			* Nothing.
339			*
340			* Side effects:
341			* Bumps the command epoch counter for the namespace, invalidating
342			* all command references in that namespace. Also bumps the
343			* resolver epoch counter for the namespace, forcing all code
344			* in the namespace to be recompiled.
345			*
346			*----------------------------------------------------------------------
347			*/
348
349			void
350			Tcl_SetNamespaceResolvers(namespacePtr, cmdProc, varProc, compiledVarProc)
351			Tcl_Namespace namespacePtr; / Namespace whose resolution rules
352			* are being modified. */
353			Tcl_ResolveCmdProc cmdProc; / Procedure for command resolution */
354			Tcl_ResolveVarProc varProc; / Procedure for variable resolution
355			* at runtime */
356			Tcl_ResolveCompiledVarProc *compiledVarProc;
357			/* Procedure for variable resolution
358			* at compile time. */
359			{
360			Namespace nsPtr = (Namespace)namespacePtr;
361
362			/*
363			* Plug in the new command resolver, and bump the epoch counters
364			* so that all code will have to be recompiled and all commands
365			* will have to be resolved again using the new policy.
366			*/
367			nsPtr->cmdResProc = cmdProc;
368			nsPtr->varResProc = varProc;
369			nsPtr->compiledVarResProc = compiledVarProc;
370
371			nsPtr->cmdRefEpoch++;
372			nsPtr->resolverEpoch++;
373			}
374
375			/*
376			*----------------------------------------------------------------------
377			*
378			* Tcl_GetNamespaceResolvers --
379			*
380			* Returns the current command/variable resolution procedures
381			* for a namespace. By default, these procedures are NULL.
382			* New procedures can be installed by calling
383			* Tcl_SetNamespaceResolvers, to provide new name resolution
384			* rules.
385			*
386			* Results:
387			* Returns non-zero if any name resolution procedures have been
388			* assigned to this namespace; also returns pointers to the
389			* procedures in the Tcl_ResolverInfo structure. Returns zero
390			* otherwise.
391			*
392			* Side effects:
393			* None.
394			*
395			*----------------------------------------------------------------------
396			*/
397
398			int
399			Tcl_GetNamespaceResolvers(namespacePtr, resInfoPtr)
400
401			Tcl_Namespace namespacePtr; / Namespace whose resolution rules
402			* are being modified. */
403			Tcl_ResolverInfo resInfoPtr; / Returns: pointers for all
404			* name resolution procedures
405			* assigned to this namespace. */
406			{
407			Namespace nsPtr = (Namespace)namespacePtr;
408
409			resInfoPtr->cmdResProc = nsPtr->cmdResProc;
410			resInfoPtr->varResProc = nsPtr->varResProc;
411			resInfoPtr->compiledVarResProc = nsPtr->compiledVarResProc;
412
413			if (nsPtr->cmdResProc != NULL \|\|
414			nsPtr->varResProc != NULL \|\|
415			nsPtr->compiledVarResProc != NULL) {
416			return 1;
417			}
418			return 0;
419			}
420
421			/* End of tclresolve.c */