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Volume Number: | 7 | |
Issue Number: | 9 | |
Column Tag | Pascal Procedures |
Related Info: Menu Manager
Menu Command Handler Unit
By David T. Craig, Kansas City, MO
Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.
[David has been involved with the Macintosh on the software side since its introduction in 1984. Currently he works as a Macintosh programmer for a small custom application development company in Kansas City, Kansas.]
Introduction
This unit manages menu commands in a manner similar to Apple’s MacApp “command menu” mechanism. Each application menu item should contain a unique “command number”, an integer value in the range 1 to 32767. This module scans the installed menus, parses the command numbers from each menu item, and stores the item command numbers in a table. When a menu item is selected, this module should be called to return the command number of the selected item. The parsed menu command number is also removed from the menu item.
Having each menu item define its own unique command value simplifies the job of the application programmer. Instead of using the menu id and menu item values for menu handling, the programmer needs only to use the unique command numbers. Using command numbers allows the programmer to move menu items around in the resource file without having to change the application source code. Users also benefit since they too can move menu items around via ResEdit as long as they don’t alter the item’s command number.
A menu item has a command number if the menu contains the character “#” followed by the command number. An example follows for a typical file menu (format compatible with Apple’s MPW Rez tool):
#1 “New#1”,noicon,nokey,nomark, plain; “Open...#2”,noicon,”O”,nomark,plain; “-”,noicon,nokey,nomark,plain; “Quit#3”, noicon,”Q”,nomark,plain;
Note that the command number must exist at the menu item’s end.
Using this Unit
This module contains several routines which completely control access to menu command numbers.
Routine MC_Build_Menu_Command_Table builds the menu command table for an application. Call this at the start of an application after the application menus have been installed. This routine takes a pointer to a list of menu handles which define all the application menus. In Pascal a simple array of MenuHandle is adequate.
Once you are completely finished with all the menus call routine MC_UnBuild_Menu_Command_Table. This should generally be called when the application quits.
Routine MC_Fetch_Menu_Command should be called when the user selects a menu item via either the ROM MenuSelect or ROM MenuKey routines. This routine returns the command number for the selected menu item.
Routine MC_Fetch_Menu_ID_and_Item returns the menu id and item numbers for a menu command number. Once this routine is used you may use the command’s id and item numbers with the many routines supported by the Apple Menu Manager.
Routine MC_Version returns the version number and compilation date and time of this module.
Applications supporting menus that change may also use this module (MicroSoft Word is an example of an application with changing menus). Whenever the menus change you must deallocate the built menu command table and rebuild the new menu command table.
WARNING: The caller of these routines must not make any assumptions about the contents of a menu command table. This data structure, which is referenced thru a handle, must be considered off limits since its internal layout may change. Use only the public routines in this module and you will have no problems.
Unit Interface Routines PROCEDURE MC_Version (VAR version_phrase: Str255); PROCEDURE MC_Build_Menu_Command_Table (menu_list: Ptr; menu_count: INTEGER; VAR command_table: Handle; VAR good_build: BOOLEAN); PROCEDURE MC_UnBuild_Menu_Command_Table (VAR command_table: Handle; VAR good_unbuild: BOOLEAN); PROCEDURE MC_Fetch_Menu_Command (command_table: Handle; menu_info: LONGINT; VAR menu_command: INTEGER); PROCEDURE MC_Fetch_Menu_ID_and_Item (command_table: Handle; menu_command: INTEGER; VAR menu_id: INTEGER; VAR menu_item: INTEGER);
Listing: UMenuCommand.p { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • • } { • ---------------------------------------------- • } { • APPLE MACINTOSH MENU COMMAND PARSER MODULE • } { • ---------------------------------------------- • } { • • } { • Author ...... David T. Craig • } { • Address ..... 736 Edgewater, Wichita, Kansas 67230 • } { • Date ........ 1989/1990 • } { • Version ..... 1.0.0 • } { • Language .... Apple MPW and Think Pascal 3.0 • } { • Computer .... Apple Macintosh • } { • • } { • Copyright ... NOT Copyright (C) 1990 by David T. Craig • } { • • } { • PURPOSE: • } { • • } { • This module manages menu commands similar to Apple’s MacApp “command menu” mechanism. • } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • • } { • Modification Notes • } { • • } { • Originally written in Lisa Pascal on a Lisa, ported to MPW and thento Think Pascal. • } { • • } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • NOT COPYRIGHT 1990 BY DAVID T. CRAIG • } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } UNIT UMenuCommand; { ########################################################## } INTERFACE { ########################################################## } {$DECL for_MPW} {$SETC for_MPW:=FALSE} {$DECL for_THINK} {$SETC for_THINK:=TRUE} { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • EXTERNAL MODULES • } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } {$IFC for_MPW} USES MemTypes, QuickDraw, OSIntf, ToolIntf, PackIntf, Traps, PasLibIntf; {$ENDC} {$IFC for_THINK} USES MemTypes, QuickDraw, OSIntf, ToolIntf, Packages; {$ENDC} { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • COMPILER DIRECTIVES • } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } {$IFC for_MPW} {$R+} { array, string, & subrange range checking [MPW PASCAL 3.0] } {$OV+} { integer overflow checking [MPW PASCAL 3.0] } {$SC+} { short-circuit boolean evaluation [MPW PASCAL 3.0] } {$ENDC} {$IFC for_THINK} {$R+} { array, string,& subrange range checking [THINK PASCAL 3.0] } {$N+} { routine name inclusion for debugger [THINK PASCAL 3.0] } {$V+} { integer overflow checking [THINK PASCAL 3.0] } {$ENDC} { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • PUBLIC MODULE INTERFACE • } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } CONST MC_c_NoCommand = 0; { menu command value for NO COMMAND } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • Routine ... MC_Version } { • Purpose ... Return the version number and compilation date of the module } { • Input ..... (none) } { • Output .... version_phrase - version number and compilation date info } { • Notes ..... Use this if you are interested in having this information. } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } PROCEDURE MC_Version (VAR version_phrase: Str255); { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • Routine ... MC_Build_Menu_Command_Table } { • Purpose ... Build a new menu command tabe from a list of menus } { • Input ..... menu_list - pointer to list of menus to build from } { • menu_count - no. menus in the menu list } { • Output .... command_table - build menu command table } { • good_build - build went well flag } { • Notes ..... Call this routine after your application’s menus are defined. } { • Using an array of MenuHandles for the menu list is an easy way to pass the menus to this routine. Duplicate command numbers are detected and result in good_build returning False. } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } PROCEDURE MC_Build_Menu_Command_Table (menu_list: Ptr; { in } menu_count: INTEGER; { in } VAR command_table: Handle; { out } VAR good_build: BOOLEAN); { out } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • Routine ... MC_UnBuild_Menu_Command_Table } { • Purpose ... Unbuild a build menu command table } { • Input ..... command_table - built menu command table } { • Output .... command_table - deallocated menu command table (=NIL) } { • good_unbuild - unbuild process went well flag } { • Notes ..... This routine should be called when you are completely done with a menu command table. } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } PROCEDURE MC_UnBuild_Menu_Command_Table (VAR command_table: Handle; { in/out } VAR good_unbuild: BOOLEAN); { in } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • Routine ... MC_Fetch_Menu_Command } { • Purpose ... Fetch the menu command command for a menu selected by the ROM Menu Manager routine MenuSelect } { • Input ..... command_table - command table from MC_Build_Menu_Command_Table } { • menu_info - menu info from ROM MenuSelect } { • Output .... menu_command - selected menu command value (0=no command) } { • Notes ..... Call this routine when the user has selected a menu and you have called ROM MenuSelect or ROM MenuKey. } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } PROCEDURE MC_Fetch_Menu_Command(command_table: Handle; {in} menu_info: LONGINT; { in } VAR menu_command: INTEGER); { out } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • Routine ... MC_Fetch_Menu_ID_and_Item } { • Purpose ... Return the menu id and item numbers for a command number } { • Input ..... command_table - command table from MC_Build_Menu_Command_Table } { • menu_command - menu command number } { • Output .... menu_id - menu id value for the command number } { • menu_item - menu item value for the command number } { • Notes ..... If the command number is invalid, then menu_id and menu_item are set to -1, an invalid value for either of these numbers. } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } PROCEDURE MC_Fetch_Menu_ID_and_Item(command_table:Handle;{in} menu_command: INTEGER; { in } VAR menu_id: INTEGER; { out } VAR menu_item: INTEGER); { out } { ########################################################## } IMPLEMENTATION { ########################################################## } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • PRIVATE MODULE CONSTANTS • } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } CONST pc_module_version = ‘1.0.0’; { module version number } pc_command_identifier = ‘#’;{ command # character for menus} pc_command_num_min = 1; { min and max menu command values } pc_command_num_max = MAXINT; { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • PRIVATE MODULE TYPES • } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } TYPE { general data types } pt_word = 0..MAXINT; { list of menu handles used indirectly by callers } pt_menu_list = ARRAY[1..1] OF MenuHandle; pt_menu_list_ptr = ^pt_menu_list; { menu command structure for a single menu item } pt_command_info = RECORD ci_command_number: INTEGER;{ unique command number } ci_menu_id: INTEGER; { menu id number for command } ci_menu_item: pt_word; { menu item number for command } END; pt_command_list = ARRAY[1..1] OF pt_command_info; pt_command_list_p = ^pt_command_list; pt_command_list_h = ^pt_command_list_p; { NOTE: The menu commands for all the menus in an application are stored as a dynamic array structure. This structure acts just like a simple array, but its size may vary. Access to the elements of this array requires disabling range checking since the array from Pascal’s perspective contains only a single element } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • • } { • PRIVATE MODULE ROUTINES • } { • • } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • Routine ... find_Command_in_Table } { • Purpose ... Attempt to locate a command number in a menu command table } { • Input ..... the_command_table - menu command table } { • the_command - command number to find } { • Output .... the_table_index - index of found command number (0=not found) } { • the_command_info - info about the found command } { • Notes ..... Output parm the_table_index is set to 0 (zero) if the command number does not exist in menu command table. } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } PROCEDURE find_Command_in_Table (the_command_table: pt_command_list_h; { in } the_command: INTEGER; { in } VAR the_table_index: pt_word; { out } VAR the_command_info: pt_command_info); { out } VAR list_size: Size; { physical byte size of command list } list_records: pt_word; { no. records in command list } error: INTEGER; { error result for a MemMgr call } BEGIN { ---------- find_Command_in_Table ---------- } the_table_index := 0; { assume the command does not exist in the table } IF the_command_table <> NIL THEN BEGIN list_size := GetHandleSize(Handle(the_command_table)); error := MemError; IF (error = NoErr) AND (list_size > 0) THEN BEGIN list_records := list_size DIV SIZEOF(the_command_info); WHILE (list_records >= 1) AND (the_table_index = 0) DO BEGIN {$PUSH} {$R-} the_command_info := the_command_table^^[list_records]; {$POP} IF the_command = the_command_info.ci_command_number THEN BEGIN the_table_index := list_records; { !!! GOTCHA !!! } END; list_records := list_records - 1; END; { WHILE list_records } END; END; END; { ---------- find_Command_in_Table ---------- } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • Routine ... add_Command_to_CmdList } { • Purpose ... Add a single menu command structure to the end of an } { • existing menu command table } { • Input ..... the_command_table - menu command table } { • the_menu_id - menu id value } { • the_menu_item - menu item value } { • the_command_number - menu command number } { • Output .... the_error - error result } { • Notes ..... Command table must already exist for this routine to work. } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } PROCEDURE add_Command_to_CmdList (the_command_table: pt_command_list_h; the_menu_id: INTEGER; the_menu_item: pt_word; the_command_number: INTEGER; VAR the_error: INTEGER); VAR command_to_add: pt_command_info;{info about command toadd} list_size: Size; { physical byte size of command list } list_records: pt_word; { no. records in command list } BEGIN { ---------- add_Command_to_CmdList ---------- } the_error := NoErr; IF the_command_table = NIL THEN the_error := NILHandleErr ELSE BEGIN { setup the command info to actually add to the table end } command_to_add.ci_command_number := the_command_number; command_to_add.ci_menu_id := the_menu_id; command_to_add.ci_menu_item := the_menu_item; { grow the table by one record for the addition } list_size := GetHandleSize(Handle(the_command_table)); the_error := MemError; IF the_error = NoErr THEN BEGIN list_size := list_size + SIZEOF(command_to_add); SetHandleSize(Handle(the_command_table), list_size); the_error := MemError; { store the command info record at the end of the table } IF the_error = NoErr THEN BEGIN list_records := list_size DIV SIZEOF(command_to_add); {$PUSH} {$R-} the_command_table^^[list_records] := command_to_add; {$POP} END; END; END; END; { ---------- add_Command_to_CmdList ---------- } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • • } { • PUBLIC MODULE ROUTINES • } { • • } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • Routine ... MC_Version } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } PROCEDURE MC_Version (VAR version_phrase: Str255); VAR comp_stuff: STRING[63]; { compilation date and time info } BEGIN { ---------- MC_Version ---------- } { NOTE: COMPDATE and COMPTIME contain the compilation date and time as strings. These are both built into MPW Pascal and THINK Pascal. MPW treats them as string constants while THINK treats them as string functions. } comp_stuff := CONCAT(‘[‘, COMPDATE, ‘ -- ‘, COMPTIME, ‘]’); version_phrase := CONCAT(pc_module_version, ‘ ‘, comp_stuff); END; { ---------- MC_Version ---------- } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • Routine ... MC_Build_Menu_Command_Table } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } PROCEDURE MC_Build_Menu_Command_Table (menu_list: Ptr; menu_count: INTEGER; VAR command_table: Handle; VAR good_build: BOOLEAN); VAR menu_index: pt_word;{ menuhandle list indexer } menu_list_ptr: pt_menu_list_ptr; { menu list pointer } menu_stuff: MenuHandle; { single entry from menu list } menu_id: INTEGER; { menu id value from menu list entry } menu_item: pt_word; {menuitem value from menu list entry} menu_phrase: Str255; { phrase for a single menu item } command_identifier: STRING[1]; { command identifier character } command_position: pt_word; { position of command identifier in item } command_phrase: Str255; { menu command number phrase (eg: “203”) } command_number: LONGINT; { command number value (long) } command_value: INTEGER; { command number value (word) } table_index: pt_word; { menu command table index of a command } command_info: pt_command_info; { information about a single menu command } good_unbuild: BOOLEAN; { deallocating menu command table result } error: INTEGER; { internal error result } BEGIN { ------ MC_Build_Menu_Command_Table ------ } command_table := NIL; good_build := FALSE; IF menu_count >= 1 THEN BEGIN command_table := NewHandle(0); error := MemError; IF error = NoErr THEN BEGIN good_build := TRUE; { assume all will go well from now on } menu_index := 0; { scan each of the menu handles } REPEAT BEGIN menu_index := menu_index + 1; menu_list_ptr := pt_menu_list_ptr(menu_list); {$PUSH} {$R-} menu_stuff := menu_list_ptr^[menu_index]; {$POP} IF menu_stuff <> NIL THEN BEGIN command_identifier := ‘?’; command_identifier[1] := pc_command_identifier; { scan the menu items in the current menu handle } menu_id := menu_stuff^^.MenuID; menu_item := 0; REPEAT BEGIN menu_item := menu_item + 1; GetItem(menu_stuff, menu_item, menu_phrase); IF LENGTH(menu_phrase) >= 2 THEN BEGIN command_position := POS(command_identifier, menu_phrase); IF command_position > 0 THEN BEGIN command_phrase := COPY(menu_phrase, command_position, LENGTH(menu_phrase) - command_position + 1); DELETE(command_phrase, 1, 1); DELETE(menu_phrase, command_position, LENGTH(menu_phrase) - command_position + 1); SetItem(menu_stuff, menu_item, menu_phrase); WHILE POS(‘ ‘, command_phrase) > 0 DO DELETE(command_phrase, POS(‘ ‘, command_phrase), 1); StringToNum(command_phrase, command_number); command_value := LoWord(command_number); IF (command_value < pc_command_num_min) OR (command_value > pc_command_num_max) THEN good_build := FALSE ELSE BEGIN { command value is valid, now check for duplication } find_Command_in_Table( pt_command_list_h(command_table), command_value, table_index, command_info); IF table_index > 0 THEN good_build := FALSE { !!! DUPLICATE !!! } ELSE BEGIN add_Command_to_CmdList (pt_command_list_h(command_table), menu_id, menu_item, command_value, error); IF error <> NoErr THEN good_build := FALSE; END; END; END; END; END; UNTIL (menu_phrase = ‘’) OR NOT (good_build); END; IF error <> NoErr THEN good_build := FALSE; END; UNTIL (menu_index >= menu_count) OR (error <> NoErr); END; END; IF NOT (good_build) AND (command_table <> NIL) THEN BEGIN MC_UnBuild_Menu_Command_Table(command_table, good_unbuild); END; END; { ------ MC_Build_Menu_Command_Table ------ } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • Routine ... MC_UnBuild_Menu_Command_Table } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } PROCEDURE MC_UnBuild_Menu_Command_Table (VAR command_table: Handle; VAR good_unbuild: BOOLEAN); VAR error: INTEGER; BEGIN { ------ MC_UnBuild_Menu_Command_Table ------ } good_unbuild := TRUE; IF command_table = NIL THEN good_unbuild := FALSE ELSE BEGIN DisposHandle(command_table); error := MemError; IF error <> NoErr THEN good_unbuild := FALSE; command_table := NIL; END; END; { ------ MC_UnBuild_Menu_Command_Table ------ } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • Routine ... MC_Fetch_Menu_Command } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } PROCEDURE MC_Fetch_Menu_Command (command_table: Handle; menu_info: LONGINT; VAR menu_command: INTEGER); TYPE t_menu_selection = RECORD ms_menu_id: INTEGER; ms_menu_item: INTEGER; END; VAR menu_selection: t_menu_selection; { info about selected menu item } cmd_table: pt_command_list_h;{ menu command table } command_info: pt_command_info; { menu command info } list_size: Size; { physical byte size of command list } list_records: pt_word; { no. records in command list } BEGIN { ---------- MC_Fetch_Menu_Command ---------- } { assume the command will NOT be found } menu_command := MC_c_NoCommand; { determine the selected menu ID and menu ITEM } menu_selection := t_menu_selection(menu_info); IF command_table <> NIL THEN BEGIN cmd_table := pt_command_list_h(command_table); list_size := GetHandleSize(command_table); list_records := list_size DIV SIZEOF(command_info); WHILE list_records >= 1 DO BEGIN {$PUSH} {$R-} command_info := cmd_table^^[list_records]; {$POP} WITH menu_selection, command_info DO IF (ms_menu_id = ci_menu_id) AND (ms_menu_item = ci_menu_item) THEN BEGIN menu_command := ci_command_number; { !!! GOTCHA !!! } END; list_records := list_records - 1; END; { WHILE list_records } END; END; { ---------- MC_Fetch_Menu_Command ---------- } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • Routine ... MC_Fetch_Menu_ID_and_Item } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } PROCEDURE MC_Fetch_Menu_ID_and_Item (command_table: Handle; { in } menu_command: INTEGER; { in } VAR menu_id: INTEGER; { out } VAR menu_item: INTEGER); { out } VAR command_info: pt_command_info; { menu command info } table_index: pt_word; { index of command in menu command table } BEGIN { ---------- MC_Fetch_Menu_ID_and_Item ---------- } { assume no command match will occur } menu_id := -1; menu_item := -1; { attempt to locate the inputted command in the menu command table } IF command_table <> NIL THEN BEGIN find_Command_in_Table(pt_command_list_h(command_table), menu_command, table_index, command_info); IF table_index >= 1 THEN BEGIN { command found in table --> return command’s menu stuff } menu_id := command_info.ci_menu_id; menu_item := command_info.ci_menu_item; END; END; END; { ---------- MC_Fetch_Menu_ID_and_Item ---------- } END. { UNIT UMenuCommand } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• } { • • } { • FINIS • } { • • } { •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• }
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