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Tcl_Ensemble(3tcl) Tcl Library Procedures Tcl_Ensemble(3tcl) 





NAME


Tcl_CreateEnsemble, Tcl_FindEnsemble, Tcl_GetEnsembleFlags,
    Tcl_GetEnsembleMappingDict, Tcl_GetEnsembleNamespace,
    Tcl_GetEnsembleParameterList, Tcl_GetEnsembleUnknownHandler,
    Tcl_GetEnsembleSubcommandList, Tcl_IsEnsemble, Tcl_SetEnsembleFlags,
    Tcl_SetEnsembleMappingDict, Tcl_SetEnsembleParameterList,
    Tcl_SetEnsembleSubcommandList, Tcl_SetEnsembleUnknownHandler - manipulate
    ensemble commands






SYNOPSIS


#include <tcl.h>

Tcl_Command
Tcl_CreateEnsemble(interp, name, namespacePtr, ensFlags)

Tcl_Command
Tcl_FindEnsemble(interp, cmdNameObj, flags)

int
Tcl_IsEnsemble(token)

int
Tcl_GetEnsembleFlags(interp, token, ensFlagsPtr)

int
Tcl_SetEnsembleFlags(interp, token, ensFlags)

int
Tcl_GetEnsembleMappingDict(interp, token, dictObjPtr)

int
Tcl_SetEnsembleMappingDict(interp, token, dictObj)

int
Tcl_GetEnsembleParameterList(interp, token, listObjPtr)

int
Tcl_SetEnsembleParameterList(interp, token, listObj)

int
Tcl_GetEnsembleSubcommandList(interp, token, listObjPtr)

int
Tcl_SetEnsembleSubcommandList(interp, token, listObj)

int
Tcl_GetEnsembleUnknownHandler(interp, token, listObjPtr)

int
Tcl_SetEnsembleUnknownHandler(interp, token, listObj)

int
Tcl_GetEnsembleNamespace(interp, token, namespacePtrPtr)






ARGUMENTS



  
Tcl_Interp *interp (in/out)

  
The interpreter in which the ensemble is to be created or found. Also
      where error result messages are written. The functions whose names start
      with Tcl_GetEnsemble may have a NULL for the interp, but all
      other functions must not.

  
const char *name (in)

  
The name of the ensemble command to be created.

  
Tcl_Namespace *namespacePtr (in)

  
The namespace to which the ensemble command is to be bound, or NULL for
      the current namespace.

  
int ensFlags (in)

  
An ORed set of flag bits describing the basic configuration of the
      ensemble. Currently only one bit has meaning, TCL_ENSEMBLE_PREFIX,
      which is present when the ensemble command should also match unambiguous
      prefixes of subcommands.

  
Tcl_Obj *cmdNameObj (in)

  
A value holding the name of the ensemble command to look up.

  
int flags (in)

  
An ORed set of flag bits controlling the behavior of
      Tcl_FindEnsemble. Currently only TCL_LEAVE_ERR_MSG is
      supported.

  
Tcl_Command token (in)

  
A normal command token that refers to an ensemble command, or which you
      wish to use for testing as an ensemble command in
    Tcl_IsEnsemble.

  
int *ensFlagsPtr (out)

  
Pointer to a variable into which to write the current ensemble flag bits;
      currently only the bit TCL_ENSEMBLE_PREFIX is defined.

  
Tcl_Obj *dictObj (in)

  
A dictionary value to use for the subcommand to implementation command
      prefix mapping dictionary in the ensemble. May be NULL if the mapping
      dictionary is to be removed.

  
Tcl_Obj **dictObjPtr (out)

  
Pointer to a variable into which to write the current ensemble mapping
      dictionary.

  
Tcl_Obj *listObj (in)

  
A list value to use for the list of formal pre-subcommand parameters, the
      defined list of subcommands in the dictionary or the unknown subcommand
      handler command prefix. May be NULL if the subcommand list or unknown
      handler are to be removed.

  
Tcl_Obj **listObjPtr (out)

  
Pointer to a variable into which to write the current list of formal
      pre-subcommand parameters, the defined list of subcommands or the current
      unknown handler prefix.

  
Tcl_Namespace **namespacePtrPtr (out)

  
Pointer to a variable into which to write the handle of the namespace to
      which the ensemble is bound.
    
    

    

  








DESCRIPTION


An ensemble is a command, bound to some namespace, which consists
    of a collection of subcommands implemented by other Tcl commands. The first
    argument to the ensemble command is always interpreted as a selector that
    states what subcommand to execute.


Ensembles are created using Tcl_CreateEnsemble, which takes
    four arguments: the interpreter to work within, the name of the ensemble to
    create, the namespace within the interpreter to bind the ensemble to, and
    the default set of ensemble flags. The result of the function is the command
    token for the ensemble, which may be used to further configure the ensemble
    using the API described below in ENSEMBLE PROPERTIES.


Given the name of an ensemble command, the token for that command
    may be retrieved using Tcl_FindEnsemble. If the given command name
    (in cmdNameObj) does not refer to an ensemble command, the result of
    the function is NULL and (if the TCL_LEAVE_ERR_MSG bit is set in
    flags) an error message is left in the interpreter result.


A command token may be checked to see if it refers to an ensemble
    using Tcl_IsEnsemble. This returns 1 if the token refers to an
    ensemble, or 0 otherwise.




ENSEMBLE PROPERTIES


Every ensemble has four read-write properties and a read-only
    property. The properties are:



  

  
The set of flags for the ensemble, expressed as a bit-field. Currently,
      the only public flag is TCL_ENSEMBLE_PREFIX which is set when
      unambiguous prefixes of subcommands are permitted to be resolved to
      implementations as well as exact matches. The flags may be read and
      written using Tcl_GetEnsembleFlags and Tcl_SetEnsembleFlags
      respectively. The result of both of those functions is a Tcl result code
      (TCL_OK, or TCL_ERROR if the token does not refer to an
      ensemble).

  

  
A dictionary containing a mapping from subcommand names to lists of words
      to use as a command prefix (replacing the first two words of the command
      which are the ensemble command itself and the subcommand name), or NULL if
      every subcommand is to be mapped to the command with the same unqualified
      name in the ensemble's bound namespace. Defaults to NULL. May be read and
      written using Tcl_GetEnsembleMappingDict and
      Tcl_SetEnsembleMappingDict respectively. The result of both of
      those functions is a Tcl result code (TCL_OK, or TCL_ERROR
      if the token does not refer to an ensemble) and the dictionary obtained
      from Tcl_GetEnsembleMappingDict should always be treated as
      immutable even if it is unshared. All command names in prefixes set via
      Tcl_SetEnsembleMappingDict must be fully qualified.

  

  
A list of formal parameter names (the names only being used when
      generating error messages) that come at invocation of the ensemble between
      the name of the ensemble and the subcommand argument. NULL (the default)
      is equivalent to the empty list. May be read and written using
      Tcl_GetEnsembleParameterList and
      Tcl_SetEnsembleParameterList respectively. The result of both of
      those functions is a Tcl result code (TCL_OK, or TCL_ERROR
      if the token does not refer to an ensemble) and the dictionary obtained
      from Tcl_GetEnsembleParameterList should always be treated as
      immutable even if it is unshared.

  

  
A list of all the subcommand names for the ensemble, or NULL if this is to
      be derived from either the keys of the mapping dictionary (see above) or
      (if that is also NULL) from the set of commands exported by the bound
      namespace. May be read and written using
      Tcl_GetEnsembleSubcommandList and
      Tcl_SetEnsembleSubcommandList respectively. The result of both of
      those functions is a Tcl result code (TCL_OK, or TCL_ERROR
      if the token does not refer to an ensemble) and the list obtained from
      Tcl_GetEnsembleSubcommandList should always be treated as immutable
      even if it is unshared.

  

  
A list of words to prepend on the front of any subcommand when the
      subcommand is unknown to the ensemble (according to the current prefix
      handling rule); see the namespace ensemble command for more
      details. If NULL, the default behavior - generate a suitable error message
      - will be used when an unknown subcommand is encountered. May be read and
      written using Tcl_GetEnsembleUnknownHandler and
      Tcl_SetEnsembleUnknownHandler respectively. The result of both
      functions is a Tcl result code (TCL_OK, or TCL_ERROR if the
      token does not refer to an ensemble) and the list obtained from
      Tcl_GetEnsembleUnknownHandler should always be treated as immutable
      even if it is unshared.

  

  
The namespace to which the ensemble is bound; when the namespace is
      deleted, so too will the ensemble, and this namespace is also the
      namespace whose list of exported commands is used if both the mapping
      dictionary and the subcommand list properties are NULL. May be read using
      Tcl_GetEnsembleNamespace which returns a Tcl result code
      (TCL_OK, or TCL_ERROR if the token does not refer to an
      ensemble).










SEE ALSO


namespace(3tcl), Tcl_DeleteCommandFromToken(3tcl)






KEYWORDS


command, ensemble







  

    8.5
    Tcl