1Tcl_Ensemble(3) Tcl Library Procedures Tcl_Ensemble(3)
2______________________________________________________________________________
6
8 Tcl_CreateEnsemble, Tcl_FindEnsemble, Tcl_GetEnsembleFlags,
9 Tcl_GetEnsembleMappingDict, Tcl_GetEnsembleNamespace, Tcl_GetEnsemble‐
10 UnknownHandler, Tcl_GetEnsembleSubcommandList, Tcl_IsEnsemble,
11 Tcl_SetEnsembleFlags, Tcl_SetEnsembleMappingDict, Tcl_SetEnsembleSub‐
12 commandList, Tcl_SetEnsembleUnknownHandler - manipulate ensemble com‐
13 mands
14
16 #include <tcl.h>
17 Tcl_Command
19 Tcl_CreateEnsemble(interp, name, namespacePtr, ensFlags)
20 Tcl_Command
22 Tcl_FindEnsemble(interp, cmdNameObj, flags)
23 int
25 Tcl_IsEnsemble(token)
26 int
28 Tcl_GetEnsembleFlags(interp, token, ensFlagsPtr)
29 int
31 Tcl_SetEnsembleFlags(interp, token, ensFlags)
32 int
34 Tcl_GetEnsembleMappingDict(interp, token, dictObjPtr)
35 int
37 Tcl_SetEnsembleMappingDict(interp, token, dictObj)
38 int
40 Tcl_GetEnsembleSubcommandList(interp, token, listObjPtr)
41 int
43 Tcl_SetEnsembleSubcommandList(interp, token, listObj)
44 int
46 Tcl_GetEnsembleUnknownHandler(interp, token, listObjPtr)
47 int
49 Tcl_SetEnsembleUnknownHandler(interp, token, listObj)
50 int
52 Tcl_GetEnsembleNamespace(interp, token, namespacePtrPtr)
53
55 Tcl_Interp *interp (in/out) The interpreter in which
56 the ensemble is to be
57 created or found. Also
58 where error result mes‐
59 sages are written. The
60 functions whose names
61 start with Tcl_GetEnsem‐
62 ble may have a NULL for
63 the interp, but all other
64 functions must not.
65 const char *name (in) The name of the ensemble
67 command to be created.
68 Tcl_Namespace *namespacePtr (in) The namespace to which
70 the ensemble command is
71 to be bound, or NULL for
72 the current namespace.
73 int ensFlags (in) An ORed set of flag bits
75 describing the basic con‐
76 figuration of the ensem‐
77 ble. Currently only one
78 bit has meaning,
79 TCL_ENSEMBLE_PREFIX,
80 which is present when the
81 ensemble command should
82 also match unambiguous
83 prefixes of subcommands.
84 Tcl_Obj *cmdNameObj (in) A value holding the name
86 of the ensemble command
87 to look up.
88 int flags (in) An ORed set of flag bits
90 controlling the behavior
91 of Tcl_FindEnsemble. Cur‐
92 rently only
93 TCL_LEAVE_ERR_MSG is sup‐
94 ported.
95 Tcl_Command token (in) A normal command token
97 that refers to an ensem‐
98 ble command, or which you
99 wish to use for testing
100 as an ensemble command in
101 Tcl_IsEnsemble.
102 int *ensFlagsPtr (out) Pointer to a variable
104 into which to write the
105 current ensemble flag
106 bits; currently only the
107 bit TCL_ENSEMBLE_PREFIX
108 is defined.
109 Tcl_Obj *dictObj (in) A dictionary value to use
111 for the subcommand to
112 implementation command
113 prefix mapping dictionary
114 in the ensemble. May be
115 NULL if the mapping dic‐
116 tionary is to be removed.
117 Tcl_Obj **dictObjPtr (out) Pointer to a variable
119 into which to write the
120 current ensemble mapping
121 dictionary.
122 Tcl_Obj *listObj (in) A list value to use for
124 the defined list of sub‐
125 commands in the dictio‐
126 nary or the unknown sub‐
127 commmand handler command
128 prefix. May be NULL if
129 the subcommand list or
130 unknown handler are to be
131 removed.
132 Tcl_Obj **listObjPtr (out) Pointer to a variable
134 into which to write the
135 current defiend list of
136 subcommands or the cur‐
137 rent unknown handler pre‐
138 fix.
139 Tcl_Namespace **namespacePtrPtr (out) Pointer to a variable
141 into which to write the
142 handle of the namespace
143 to which the ensemble is
144 bound.
145_________________________________________________________________
146
149 An ensemble is a command, bound to some namespace, which consists of a
150 collection of subcommands implemented by other Tcl commands. The first
151 argument to the ensemble command is always interpreted as a selector
152 that states what subcommand to execute.
153 Ensembles are created using Tcl_CreateEnsemble, which takes four argu‐
155 ments: the interpreter to work within, the name of the ensemble to cre‐
156 ate, the namespace within the interpreter to bind the ensemble to, and
157 the default set of ensemble flags. The result of the function is the
158 command token for the ensemble, which may be used to further configure
159 the ensemble using the API descibed below in ENSEMBLE PROPERTIES.
160 Given the name of an ensemble command, the token for that command may
162 be retrieved using Tcl_FindEnsemble. If the given command name (in cmd‐
163 NameObj) does not refer to an ensemble command, the result of the func‐
164 tion is NULL and (if the TCL_LEAVE_ERR_MSG bit is set in flags) an
165 error message is left in the interpreter result.
166 A command token may be checked to see if it refers to an ensemble using
168 Tcl_IsEnsemble. This returns 1 if the token refers to an ensemble, or 0
169 otherwise.
170 ENSEMBLE PROPERTIES
172 Every ensemble has four read-write properties and a read-only property.
173 The properties are:
174 flags (read-write)
176 The set of flags for the ensemble, expressed as a bit-field.
177 Currently, the only public flag is TCL_ENSEMBLE_PREFIX which is
178 set when unambiguous prefixes of subcommands are permitted to be
179 resolved to implementations as well as exact matches. The flags
180 may be read and written using Tcl_GetEnsembleFlags and
181 Tcl_SetEnsembleFlags respectively. The result of both of those
182 functions is a Tcl result code (TCL_OK, or TCL_ERROR if the
183 token does not refer to an ensemble).
184 mapping dictionary (read-write)
186 A dictionary containing a mapping from subcommand names to lists
187 of words to use as a command prefix (replacing the first two
188 words of the command which are the ensemble command itself and
189 the subcommand name), or NULL if every subcommand is to be
190 mapped to the command with the same unqualified name in the
191 ensemble's bound namespace. Defaults to NULL. May be read and
192 written using Tcl_GetEnsembleMappingDict and Tcl_SetEnsembleMap‐
193 pingDict respectively. The result of both of those functions is
194 a Tcl result code (TCL_OK, or TCL_ERROR if the token does not
195 refer to an ensemble) and the dictionary obtained from
196 Tcl_GetEnsembleMappingDict should always be treated as immutable
197 even if it is unshared.
198 subcommand list (read-write)
200 A list of all the subcommand names for the ensemble, or NULL if
201 this is to be derived from either the keys of the mapping dic‐
202 tionary (see above) or (if that is also NULL) from the set of
203 commands exported by the bound namespace. May be read and writ‐
204 ten using Tcl_GetEnsembleSubcommandList and Tcl_SetEnsembleSub‐
205 commandList respectively. The result of both of those functions
206 is a Tcl result code (TCL_OK, or TCL_ERROR if the token does not
207 refer to an ensemble) and the list obtained from Tcl_GetEnsem‐
208 bleSubcommandList should alays be treated as immutable even if
209 it is unshared.
210 unknown subcommand handler command prefix (read-write)
212 A list of words to prepend on the front of any subcommand when
213 the subcommand is unknown to the ensemble (according to the cur‐
214 rent prefix handling rule); see the namespace ensemble command
215 for more details. If NULL, the default behavior - generate a
216 suitable error message - will be used when an unknown subcommand
217 is encountered. May be read and written using Tcl_GetEnsembleUn‐
218 knownHandler and Tcl_SetEnsembleUnknownHandler respectively. The
219 result of both functions is a Tcl result code (TCL_OK, or
220 TCL_ERROR if the token does not refer to an ensemble) and the
221 list obtained from Tcl_GetEnsembleUnknownHandler should always
222 be treated as immutable even if it is unshared.
223 bound namespace (read-only)
225 The namespace to which the ensemble is bound; when the namespace
226 is deleted, so too will the ensemble, and this namespace is also
227 the namespace whose list of exported commands is used if both
228 the mapping dictionary and the subcommand list properties are
229 NULL. May be read using Tcl_GetEnsembleNamespace which returns a
230 Tcl result code (TCL_OK, or TCL_ERROR if the token does not
231 refer to an ensemble).
232
235 namespace(n), Tcl_DeleteCommandFromToken(3)
236Tcl 8.5 Tcl_Ensemble(3)