path: root/doc/Namespace.3

'\"
'\" Copyright (c) 2003 Donal K. Fellows
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
'\" Note that some of these functions do not seem to belong, but they
'\" were all introduced with the same TIP (#139)
'\"
.TH Tcl_Namespace 3 8.5 Tcl "Tcl Library Procedures"
.so man.macros
.BS
.SH NAME
Tcl_AppendExportList, Tcl_CreateNamespace, Tcl_DeleteNamespace, Tcl_Export, Tcl_FindCommand, Tcl_FindNamespace, Tcl_ForgetImport, Tcl_GetCurrentNamespace, Tcl_GetGlobalNamespace, Tcl_GetNamespaceUnknownHandler, Tcl_Import, Tcl_SetNamespaceUnknownHandler \- manipulate namespaces
.SH SYNOPSIS
.nf
\fB#include <tcl.h>\fR
.sp
Tcl_Namespace *
\fBTcl_CreateNamespace\fR(\fIinterp, name, clientData, deleteProc\fR)
.sp
\fBTcl_DeleteNamespace\fR(\fInsPtr\fR)
.sp
int
\fBTcl_AppendExportList\fR(\fIinterp, nsPtr, objPtr\fR)
.sp
int
\fBTcl_Export\fR(\fIinterp, nsPtr, pattern, resetListFirst\fR)
.sp
int
\fBTcl_Import\fR(\fIinterp, nsPtr, pattern, allowOverwrite\fR)
.sp
int
\fBTcl_ForgetImport\fR(\fIinterp, nsPtr, pattern\fR)
.sp
Tcl_Namespace *
\fBTcl_GetCurrentNamespace\fR(\fIinterp\fR)
.sp
Tcl_Namespace *
\fBTcl_GetGlobalNamespace\fR(\fIinterp\fR)
.sp
Tcl_Namespace *
\fBTcl_FindNamespace\fR(\fIinterp, name, contextNsPtr, flags\fR)
.sp
Tcl_Command
\fBTcl_FindCommand\fR(\fIinterp, name, contextNsPtr, flags\fR)
.sp
Tcl_Obj *
\fBTcl_GetNamespaceUnknownHandler\fR(\fIinterp, nsPtr\fR)
.sp
int
\fBTcl_SetNamespaceUnknownHandler\fR(\fIinterp, nsPtr, handlerPtr\fR)
.SH ARGUMENTS
.AS Tcl_NamespaceDeleteProc allowOverwrite in/out
.AP Tcl_Interp *interp in/out
The interpreter in which the namespace exists and where name lookups
are performed. Also where error result messages are written.
.AP "const char" *name in
The name of the namespace or command to be created or accessed.
.AP void *clientData in
A context pointer by the creator of the namespace.  Not interpreted by
Tcl at all.
.AP Tcl_NamespaceDeleteProc *deleteProc in
A pointer to function to call when the namespace is deleted, or NULL
if no such callback is to be performed.
.AP Tcl_Namespace *nsPtr in
The namespace to be manipulated, or NULL (for other than
\fBTcl_DeleteNamespace\fR) to manipulate the current namespace.
.AP Tcl_Obj *objPtr out
A reference to an unshared value to which the function output will be
written.
.AP "const char" *pattern in
The glob-style pattern (see \fBTcl_StringMatch\fR) that describes the
commands to be imported or exported.
.AP int resetListFirst in
Whether the list of export patterns should be reset before adding the
current pattern to it.
.AP int allowOverwrite in
Whether new commands created by this import action can overwrite
existing commands.
.AP Tcl_Namespace *contextNsPtr in
The location in the namespace hierarchy where the search for a
namespace or command should be conducted relative to when the search
term is not rooted at the global namespace.  NULL indicates the
current namespace.
.AP int flags in
OR-ed combination of bits controlling how the search is to be
performed.  The following flags are supported: \fBTCL_GLOBAL_ONLY\fR
(indicates that the search is always to be conducted relative to the
global namespace), \fBTCL_NAMESPACE_ONLY\fR (just for \fBTcl_FindCommand\fR;
indicates that the search is always to be conducted relative to the
context namespace), and \fBTCL_LEAVE_ERR_MSG\fR (indicates that an error
message should be left in the interpreter if the search fails.)
.AP Tcl_Obj *handlerPtr in
A script fragment to be installed as the unknown command handler for the
namespace, or NULL to reset the handler to its default.
.BE
.SH DESCRIPTION
.PP
Namespaces are hierarchic naming contexts that can contain commands
and variables.  They also maintain a list of patterns that describes
what commands are exported, and can import commands that have been
exported by other namespaces.  Namespaces can also be manipulated
through the Tcl command \fBnamespace\fR.
.PP
The \fITcl_Namespace\fR structure encapsulates a namespace, and is
guaranteed to have the following fields in it: \fIname\fR (the local
name of the namespace, with no namespace separator characters in it,
with empty denoting the global namespace), \fIfullName\fR (the fully
specified name of the namespace), \fIclientData\fR, \fIdeleteProc\fR
(the values specified in the call to \fBTcl_CreateNamespace\fR), and
\fIparentPtr\fR (a pointer to the containing namespace, or NULL for
the global namespace.)
.PP
\fBTcl_CreateNamespace\fR creates a new namespace.  The
\fIdeleteProc\fR will have the following type signature:
.PP
.CS
typedef void \fBTcl_NamespaceDeleteProc\fR(
        void *\fIclientData\fR);
.CE
.PP
\fBTcl_DeleteNamespace\fR deletes a namespace, calling the
\fIdeleteProc\fR defined for the namespace (if any).
.PP
\fBTcl_AppendExportList\fR retrieves the export patterns for a
namespace given namespace and appends them (as list items) to
\fIobjPtr\fR.
.PP
\fBTcl_Export\fR sets and appends to the export patterns for a
namespace.  Patterns are appended unless the \fIresetListFirst\fR flag
is true.
.PP
\fBTcl_Import\fR imports commands matching a pattern into a
namespace.  Note that the pattern must include the name of the
namespace to import from.  This function returns an error if
an attempt to import a command over an existing command is made,
unless the \fIallowOverwrite\fR flag has been set.
.PP
\fBTcl_ForgetImport\fR removes imports matching a pattern.
.PP
\fBTcl_GetCurrentNamespace\fR returns the current namespace for an
interpreter.
.PP
\fBTcl_GetGlobalNamespace\fR returns the global namespace for an
interpreter.
.PP
\fBTcl_FindNamespace\fR searches for a namespace named \fIname\fR
within the context of the namespace \fIcontextNsPtr\fR.  If the
namespace cannot be found, NULL is returned.
.PP
\fBTcl_FindCommand\fR searches for a command named \fIname\fR within
the context of the namespace \fIcontextNsPtr\fR.  If the command
cannot be found, NULL is returned.
.PP
\fBTcl_GetNamespaceUnknownHandler\fR returns the unknown command handler
for the namespace, or NULL if none is set.
.PP
\fBTcl_SetNamespaceUnknownHandler\fR sets the unknown command handler for
the namespace. If \fIhandlerPtr\fR is NULL, then the handler is reset to
its default.
.SH "REFERENCE COUNT MANAGEMENT"
.PP
The \fIobjPtr\fR argument to \fBTcl_AppendExportList\fR should be an
unshared object, as it will be modified by this function. The
reference count of \fIobjPtr\fR will not be altered.
.PP
\fBTcl_GetNamespaceUnknownHandler\fR returns a possibly shared value.
Its reference count should be incremented if the value is to be
retained.
.PP
The \fIhandlerPtr\fR argument to \fBTcl_SetNamespaceUnknownHandler\fR
will have its reference count incremented if it is a non-empty list.
.SH "SEE ALSO"
Tcl_CreateCommand(3), Tcl_ListObjAppendList(3), Tcl_SetVar(3)
.SH KEYWORDS
namespace, command