| '\" |
| '\" Copyright (c) 1996-1997 Sun Microsystems, Inc. |
| '\" |
| '\" See the file "license.terms" for information on usage and redistribution |
| '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
| '\" |
| '\" RCS: @(#) $Id: ObjectType.3,v 1.7 2002/08/16 13:45:36 dkf Exp $ |
| '\" |
| '\" The definitions below are for supplemental macros used in Tcl/Tk |
| '\" manual entries. |
| '\" |
| '\" .AP type name in/out ?indent? |
| '\" Start paragraph describing an argument to a library procedure. |
| '\" type is type of argument (int, etc.), in/out is either "in", "out", |
| '\" or "in/out" to describe whether procedure reads or modifies arg, |
| '\" and indent is equivalent to second arg of .IP (shouldn't ever be |
| '\" needed; use .AS below instead) |
| '\" |
| '\" .AS ?type? ?name? |
| '\" Give maximum sizes of arguments for setting tab stops. Type and |
| '\" name are examples of largest possible arguments that will be passed |
| '\" to .AP later. If args are omitted, default tab stops are used. |
| '\" |
| '\" .BS |
| '\" Start box enclosure. From here until next .BE, everything will be |
| '\" enclosed in one large box. |
| '\" |
| '\" .BE |
| '\" End of box enclosure. |
| '\" |
| '\" .CS |
| '\" Begin code excerpt. |
| '\" |
| '\" .CE |
| '\" End code excerpt. |
| '\" |
| '\" .VS ?version? ?br? |
| '\" Begin vertical sidebar, for use in marking newly-changed parts |
| '\" of man pages. The first argument is ignored and used for recording |
| '\" the version when the .VS was added, so that the sidebars can be |
| '\" found and removed when they reach a certain age. If another argument |
| '\" is present, then a line break is forced before starting the sidebar. |
| '\" |
| '\" .VE |
| '\" End of vertical sidebar. |
| '\" |
| '\" .DS |
| '\" Begin an indented unfilled display. |
| '\" |
| '\" .DE |
| '\" End of indented unfilled display. |
| '\" |
| '\" .SO |
| '\" Start of list of standard options for a Tk widget. The |
| '\" options follow on successive lines, in four columns separated |
| '\" by tabs. |
| '\" |
| '\" .SE |
| '\" End of list of standard options for a Tk widget. |
| '\" |
| '\" .OP cmdName dbName dbClass |
| '\" Start of description of a specific option. cmdName gives the |
| '\" option's name as specified in the class command, dbName gives |
| '\" the option's name in the option database, and dbClass gives |
| '\" the option's class in the option database. |
| '\" |
| '\" .UL arg1 arg2 |
| '\" Print arg1 underlined, then print arg2 normally. |
| '\" |
| '\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $ |
| '\" |
| '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. |
| .if t .wh -1.3i ^B |
| .nr ^l \n(.l |
| .ad b |
| '\" # Start an argument description |
| .de AP |
| .ie !"\\$4"" .TP \\$4 |
| .el \{\ |
| . ie !"\\$2"" .TP \\n()Cu |
| . el .TP 15 |
| .\} |
| .ta \\n()Au \\n()Bu |
| .ie !"\\$3"" \{\ |
| \&\\$1 \\fI\\$2\\fP (\\$3) |
| .\".b |
| .\} |
| .el \{\ |
| .br |
| .ie !"\\$2"" \{\ |
| \&\\$1 \\fI\\$2\\fP |
| .\} |
| .el \{\ |
| \&\\fI\\$1\\fP |
| .\} |
| .\} |
| .. |
| '\" # define tabbing values for .AP |
| .de AS |
| .nr )A 10n |
| .if !"\\$1"" .nr )A \\w'\\$1'u+3n |
| .nr )B \\n()Au+15n |
| .\" |
| .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n |
| .nr )C \\n()Bu+\\w'(in/out)'u+2n |
| .. |
| .AS Tcl_Interp Tcl_CreateInterp in/out |
| '\" # BS - start boxed text |
| '\" # ^y = starting y location |
| '\" # ^b = 1 |
| .de BS |
| .br |
| .mk ^y |
| .nr ^b 1u |
| .if n .nf |
| .if n .ti 0 |
| .if n \l'\\n(.lu\(ul' |
| .if n .fi |
| .. |
| '\" # BE - end boxed text (draw box now) |
| .de BE |
| .nf |
| .ti 0 |
| .mk ^t |
| .ie n \l'\\n(^lu\(ul' |
| .el \{\ |
| .\" Draw four-sided box normally, but don't draw top of |
| .\" box if the box started on an earlier page. |
| .ie !\\n(^b-1 \{\ |
| \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| .\} |
| .el \}\ |
| \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' |
| .\} |
| .\} |
| .fi |
| .br |
| .nr ^b 0 |
| .. |
| '\" # VS - start vertical sidebar |
| '\" # ^Y = starting y location |
| '\" # ^v = 1 (for troff; for nroff this doesn't matter) |
| .de VS |
| .if !"\\$2"" .br |
| .mk ^Y |
| .ie n 'mc \s12\(br\s0 |
| .el .nr ^v 1u |
| .. |
| '\" # VE - end of vertical sidebar |
| .de VE |
| .ie n 'mc |
| .el \{\ |
| .ev 2 |
| .nf |
| .ti 0 |
| .mk ^t |
| \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' |
| .sp -1 |
| .fi |
| .ev |
| .\} |
| .nr ^v 0 |
| .. |
| '\" # Special macro to handle page bottom: finish off current |
| '\" # box/sidebar if in box/sidebar mode, then invoked standard |
| '\" # page bottom macro. |
| .de ^B |
| .ev 2 |
| 'ti 0 |
| 'nf |
| .mk ^t |
| .if \\n(^b \{\ |
| .\" Draw three-sided box if this is the box's first page, |
| .\" draw two sides but no top otherwise. |
| .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c |
| .\} |
| .if \\n(^v \{\ |
| .nr ^x \\n(^tu+1v-\\n(^Yu |
| \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c |
| .\} |
| .bp |
| 'fi |
| .ev |
| .if \\n(^b \{\ |
| .mk ^y |
| .nr ^b 2 |
| .\} |
| .if \\n(^v \{\ |
| .mk ^Y |
| .\} |
| .. |
| '\" # DS - begin display |
| .de DS |
| .RS |
| .nf |
| .sp |
| .. |
| '\" # DE - end display |
| .de DE |
| .fi |
| .RE |
| .sp |
| .. |
| '\" # SO - start of list of standard options |
| .de SO |
| .SH "STANDARD OPTIONS" |
| .LP |
| .nf |
| .ta 5.5c 11c |
| .ft B |
| .. |
| '\" # SE - end of list of standard options |
| .de SE |
| .fi |
| .ft R |
| .LP |
| See the \\fBoptions\\fR manual entry for details on the standard options. |
| .. |
| '\" # OP - start of full description for a single option |
| .de OP |
| .LP |
| .nf |
| .ta 4c |
| Command-Line Name: \\fB\\$1\\fR |
| Database Name: \\fB\\$2\\fR |
| Database Class: \\fB\\$3\\fR |
| .fi |
| .IP |
| .. |
| '\" # CS - begin code excerpt |
| .de CS |
| .RS |
| .nf |
| .ta .25i .5i .75i 1i |
| .. |
| '\" # CE - end code excerpt |
| .de CE |
| .fi |
| .RE |
| .. |
| .de UL |
| \\$1\l'|0\(ul'\\$2 |
| .. |
| .TH Tcl_ObjType 3 8.0 Tcl "Tcl Library Procedures" |
| .BS |
| .SH NAME |
| Tcl_RegisterObjType, Tcl_GetObjType, Tcl_AppendAllObjTypes, Tcl_ConvertToType \- manipulate Tcl object types |
| .SH SYNOPSIS |
| .nf |
| \fB#include <tcl.h>\fR |
| .sp |
| \fBTcl_RegisterObjType\fR(\fItypePtr\fR) |
| .sp |
| Tcl_ObjType * |
| \fBTcl_GetObjType\fR(\fItypeName\fR) |
| .sp |
| int |
| \fBTcl_AppendAllObjTypes\fR(\fIinterp, objPtr\fR) |
| .sp |
| int |
| \fBTcl_ConvertToType\fR(\fIinterp, objPtr, typePtr\fR) |
| .SH ARGUMENTS |
| .AS Tcl_ObjType *typeName in |
| .AP Tcl_ObjType *typePtr in |
| Points to the structure containing information about the Tcl object type. |
| This storage must live forever, |
| typically by being statically allocated. |
| .AP "CONST char" *typeName in |
| The name of a Tcl object type that \fBTcl_GetObjType\fR should look up. |
| .AP Tcl_Interp *interp in |
| Interpreter to use for error reporting. |
| .AP Tcl_Obj *objPtr in |
| For \fBTcl_AppendAllObjTypes\fR, this points to the object onto which |
| it appends the name of each object type as a list element. |
| For \fBTcl_ConvertToType\fR, this points to an object that |
| must have been the result of a previous call to \fBTcl_NewObj\fR. |
| .BE |
| |
| .SH DESCRIPTION |
| .PP |
| The procedures in this man page manage Tcl object types. |
| The are used to register new object types, |
| look up types, |
| and force conversions from one type to another. |
| .PP |
| \fBTcl_RegisterObjType\fR registers a new Tcl object type |
| in the table of all object types supported by Tcl. |
| The argument \fItypePtr\fR points to a Tcl_ObjType structure that |
| describes the new type by giving its name |
| and by supplying pointers to four procedures |
| that implement the type. |
| If the type table already contains a type |
| with the same name as in \fItypePtr\fR, |
| it is replaced with the new type. |
| The Tcl_ObjType structure is described |
| in the section \fBTHE TCL_OBJTYPE STRUCTURE\fR below. |
| .PP |
| \fBTcl_GetObjType\fR returns a pointer to the Tcl_ObjType |
| with name \fItypeName\fR. |
| It returns NULL if no type with that name is registered. |
| .PP |
| \fBTcl_AppendAllObjTypes\fR appends the name of each object type |
| as a list element onto the Tcl object referenced by \fIobjPtr\fR. |
| The return value is \fBTCL_OK\fR unless there was an error |
| converting \fIobjPtr\fR to a list object; |
| in that case \fBTCL_ERROR\fR is returned. |
| .PP |
| \fBTcl_ConvertToType\fR converts an object from one type to another |
| if possible. |
| It creates a new internal representation for \fIobjPtr\fR |
| appropriate for the target type \fItypePtr\fR |
| and sets its \fItypePtr\fR member to that type. |
| Any internal representation for \fIobjPtr\fR's old type is freed. |
| If an error occurs during conversion, it returns \fBTCL_ERROR\fR |
| and leaves an error message in the result object for \fIinterp\fR |
| unless \fIinterp\fR is NULL. |
| Otherwise, it returns \fBTCL_OK\fR. |
| Passing a NULL \fIinterp\fR allows this procedure to be used |
| as a test whether the conversion can be done (and in fact was done). |
| |
| .SH "THE TCL_OBJTYPE STRUCTURE" |
| .PP |
| Extension writers can define new object types by defining four |
| procedures, |
| initializing a Tcl_ObjType structure to describe the type, |
| and calling \fBTcl_RegisterObjType\fR. |
| The \fBTcl_ObjType\fR structure is defined as follows: |
| .CS |
| typedef struct Tcl_ObjType { |
| char *\fIname\fR; |
| Tcl_FreeInternalRepProc *\fIfreeIntRepProc\fR; |
| Tcl_DupInternalRepProc *\fIdupIntRepProc\fR; |
| Tcl_UpdateStringProc *\fIupdateStringProc\fR; |
| Tcl_SetFromAnyProc *\fIsetFromAnyProc\fR; |
| } Tcl_ObjType; |
| .CE |
| .PP |
| The \fIname\fR member describes the name of the type, e.g. \fBint\fR. |
| Extension writers can look up an object type using its name |
| with the \fBTcl_GetObjType\fR procedure. |
| The remaining four members are pointers to procedures |
| called by the generic Tcl object code: |
| .PP |
| The \fIsetFromAnyProc\fR member contains the address of a function |
| called to create a valid internal representation |
| from an object's string representation. |
| .CS |
| typedef int (Tcl_SetFromAnyProc) (Tcl_Interp *\fIinterp\fR, Tcl_Obj *\fIobjPtr\fR); |
| .CE |
| If an internal representation can't be created from the string, |
| it returns \fBTCL_ERROR\fR and puts a message |
| describing the error in the result object for \fIinterp\fR |
| unless \fIinterp\fR is NULL. |
| If \fIsetFromAnyProc\fR is successful, |
| it stores the new internal representation, |
| sets \fIobjPtr\fR's \fItypePtr\fR member to point to |
| \fIsetFromAnyProc\fR's \fBTcl_ObjType\fR, and returns \fBTCL_OK\fR. |
| Before setting the new internal representation, |
| the \fIsetFromAnyProc\fR must free any internal representation |
| of \fIobjPtr\fR's old type; |
| it does this by calling the old type's \fIfreeIntRepProc\fR |
| if it is not NULL. |
| As an example, the \fIsetFromAnyProc\fR for the builtin Tcl integer type |
| gets an up-to-date string representation for \fIobjPtr\fR |
| by calling \fBTcl_GetStringFromObj\fR. |
| It parses the string to obtain an integer and, |
| if this succeeds, |
| stores the integer in \fIobjPtr\fR's internal representation |
| and sets \fIobjPtr\fR's \fItypePtr\fR member to point to the integer type's |
| Tcl_ObjType structure. |
| Do not release \fIobjPtr\fR's old internal representation unless you |
| replace it with a new one or reset the \fItypePtr\fR member to NULL. |
| .PP |
| The \fIupdateStringProc\fR member contains the address of a function |
| called to create a valid string representation |
| from an object's internal representation. |
| .CS |
| typedef void (Tcl_UpdateStringProc) (Tcl_Obj *\fIobjPtr\fR); |
| .CE |
| \fIobjPtr\fR's \fIbytes\fR member is always NULL when it is called. |
| It must always set \fIbytes\fR non-NULL before returning. |
| We require the string representation's byte array |
| to have a null after the last byte, at offset \fIlength\fR; |
| this allows string representations that do not contain null bytes |
| to be treated as conventional null character-terminated C strings. |
| Storage for the byte array must be allocated in the heap by \fBTcl_Alloc\fR |
| or \fBckalloc\fR. Note that \fIupdateStringProc\fRs must allocate |
| enough storage for the string's bytes and the terminating null byte. |
| The \fIupdateStringProc\fR for Tcl's builtin list type, for example, |
| builds an array of strings for each element object |
| and then calls \fBTcl_Merge\fR |
| to construct a string with proper Tcl list structure. |
| It stores this string as the list object's string representation. |
| .PP |
| The \fIdupIntRepProc\fR member contains the address of a function |
| called to copy an internal representation from one object to another. |
| .CS |
| typedef void (Tcl_DupInternalRepProc) (Tcl_Obj *\fIsrcPtr\fR, Tcl_Obj *\fIdupPtr\fR); |
| .CE |
| \fIdupPtr\fR's internal representation is made a copy of \fIsrcPtr\fR's |
| internal representation. |
| Before the call, |
| \fIsrcPtr\fR's internal representation is valid and \fIdupPtr\fR's is not. |
| \fIsrcPtr\fR's object type determines what |
| copying its internal representation means. |
| For example, the \fIdupIntRepProc\fR for the Tcl integer type |
| simply copies an integer. |
| The builtin list type's \fIdupIntRepProc\fR |
| allocates a new array that points at the original element objects; |
| the elements are shared between the two lists |
| (and their reference counts are incremented to reflect the new references). |
| .PP |
| The \fIfreeIntRepProc\fR member contains the address of a function |
| that is called when an object is freed. |
| .CS |
| typedef void (Tcl_FreeInternalRepProc) (Tcl_Obj *\fIobjPtr\fR); |
| .CE |
| The \fIfreeIntRepProc\fR function can deallocate the storage |
| for the object's internal representation |
| and do other type-specific processing necessary when an object is freed. |
| For example, Tcl list objects have an \fIinternalRep.otherValuePtr\fR |
| that points to an array of pointers to each element in the list. |
| The list type's \fIfreeIntRepProc\fR decrements |
| the reference count for each element object |
| (since the list will no longer refer to those objects), |
| then deallocates the storage for the array of pointers. |
| The \fIfreeIntRepProc\fR member can be set to NULL |
| to indicate that the internal representation does not require freeing. |
| |
| .SH "SEE ALSO" |
| Tcl_NewObj, Tcl_DecrRefCount, Tcl_IncrRefCount |
| |
| .SH KEYWORDS |
| internal representation, object, object type, string representation, type conversion |