harbour-core/doc/en/menu.txt

/*
 * Copyright 1999 Chen Kedem <niki@actcom.co.il>
 *    Documentation for: __AtPrompt(), @...PROMPT, __MenuTo(), MENU TO
 *
 * See COPYING.txt for licensing terms.
 *
 */

/* $DOC$
   $TEMPLATE$
      Function
   $NAME$
      AChoice()
   $CATEGORY$
      API
   $SUBCATEGORY$
      User interface
   $ONELINER$
      Allows selection of an element from an array
   $SYNTAX$
      AChoice( <nTop>, <nLeft>, <nBottom>, <nRight>, <acMenuItems>, [<alSelableItems> | <lSelableItems>], [<cUserFunction> | <bUserBlock>], [<nInitialItem>], [<nWindowRow>] ) --> nPosition
   $ARGUMENTS$
      <nTop>           - topmost row used to display array (default 0)

      <nLeft>          - leftmost row used to display array (default 0)

      <nBottom>        - bottommost row used to display array (default MaxRow())

      <nRight>         - rightmost row used to display array (default MaxCol())

      <acMenuItems>    - the character array of items from which to select

      <alSelableItems> - an array of items, either logical or character,
                         which is used to determine if a particular item
                         may be selected.  If the type of a given item is
                         character, it is macro evaluated, and the result
                         is expected to be a logical.  A value of .T. means
                         that the item may be selected, .F. that it may not.
                         (See next argument: lSelectableItems)

      <lSelableItems>  - a logical value which is used to apply to all
                         items in acMenuItems.  If .T., all items may be
                         selected; if .F., none may be selected.
                         (See previous argument: alSelectableItems)
                         Default .T.

      <cUserFunction>  - the name of a function to be called which may
                         affect special processing of keystrokes.  It is
                         specified without parentheses or parameters.
                         When it is called, it will be supplied with the
                         parameters: nMode, nCurElement, and nRowPos.
                         Default NIL.

      <bUserBlock>     - a codeblock to be called which may
                         affect special processing of keystrokes. It
                         should be specified in the form
                         {| nMode, nCurElemenet, nRowPos | ;
                           MyFunc( nMode, nCurElemenet, nRowPos ) }.
                         Default NIL.

      <nInitialItem>   - the number of the element to be highlighted as
                         the current item when the array is initially
                         displayed.  1 origin.  Default 1.

      <nWindowRow>     - the number of the window row on which the initial
                         item is to be displayed. 0 origin.  Default 0.
   $RETURNS$
      <nPosition>  - the number of the item to be selected, or 0 if the
      selection was aborted.
   $DESCRIPTION$
      Allows selection of an element from an array.
      Please see standard CA-Cl*pper documentation for ACHOICE for
      additional detail.
   $EXAMPLES$
      aItems := { "One", "Two", "Three" }
      nChoice := AChoice( 10, 10, 20, 20, aItems )
      IF nChoice == 0
         ? "You did not choose an item"
      ELSE
         ? ;
            "You chose element", hb_ntos( nChoice ), ;
            "which has a value of", aItems[ nChoice ]
      ENDIF
   $FILES$
      Library is core
   $COMPLIANCE$
      C
   $SEEALSO$
      MENU TO
   $END$
 */

/* $DOC$
   $TEMPLATE$
      Function
   $NAME$
      __AtPrompt()
   $CATEGORY$
      API
   $SUBCATEGORY$
      User interface
   $ONELINER$
      Display a menu item on screen and define a message
   $SYNTAX$
      __AtPrompt( <nRow>, <nCol>, <cPrompt>, [<xMsg>] ) --> .F.
   $ARGUMENTS$
      <nRow> is the row number to display the menu <cPrompt>. Value could
      range from zero to MaxRow().

      <nCol> is the column number to display the menu <cPrompt>. Value
      could range from zero to MaxCol().

      <cPrompt> is the menu item character string to display.

      <xMsg> define a message to display each time this menu item is
      highlighted. <xMsg> could be a character string or code block that
      is evaluated to a character string. If <xMsg> is not specified or
      of the wrong type, an empty string ("") would be used.
   $RETURNS$
      __AtPrompt() always return .F.
   $DESCRIPTION$
      With __AtPrompt() you define and display a menu item, each call to
      __AtPrompt() add another item to the menu, to start the menu itself
      you should call the __MenuTo() function (MENU TO command). You can
      define any row and column combination and they will be displayed at
      the order of definition. After each call to __AtPrompt(), the cursor
      is placed one column to the right of the last text displayed, and
      Row() and Col() are updated.

      @...PROMPT command is preprocessed into __AtPrompt() function during
      compile time.
   $EXAMPLES$
      // display a two line menu with status line at the bottom
      // let the user select favorite day
      SET MESSAGE TO 24 CENTER
      @ 10, 2 PROMPT "Sunday" MESSAGE "This is the 1st item"
      @ 11, 2 PROMPT "Monday" MESSAGE "Now we're on the 2nd item"
      MENU TO nChoice
      DO CASE
      CASE nChoice == 0           // user press Esc key
         QUIT
      CASE nChoice == 1           // user select 1st menu item
         ? "Guess you don't like Mondays"
      CASE nChoice == 2           // user select 2nd menu item
         ? "Just another day for some"
      ENDCASE
   $STATUS$
      R
   $COMPLIANCE$
      C
   $FILES$
      Library is core
   $SEEALSO$
      AChoice(), MENU TO, SET MESSAGE, SET INTENSITY, SET WRAP, __MenuTo()
   $END$
 */

/* $DOC$
   $TEMPLATE$
      Command
   $NAME$
      @...PROMPT
   $CATEGORY$
      Command
   $SUBCATEGORY$
      User interface
   $ONELINER$
      Display a menu item on screen and define a message
   $SYNTAX$
      @ <nRow>, <nCol> PROMPT <cPrompt> [MESSAGE <xMsg>]
   $ARGUMENTS$
      <nRow> is the row number to display the menu <cPrompt>. Value could
      range from zero to MaxRow().

      <nCol> is the column number to display the menu <cPrompt>. Value
      could range from zero to MaxCol().

      <cPrompt> is the menu item character string to display.

      <xMsg> define a message to display each time this menu item is
      highlighted. <xMsg> could be a character string or code block that
      is evaluated to a character string. If <xMsg> is not specified or
      of the wrong type, an empty string ("") would be used.
   $DESCRIPTION$
      With @...Prompt you define and display a menu item, each call to
      @...Prompt add another item to the menu, to start the menu itself
      you should call the __MenuTo() function (MENU TO command). You can
      define any row and column combination and they will be displayed at
      the order of definition. After each call to @...Prompt, the cursor
      is placed one column to the right of the last text displayed, and
      Row() and Col() are updated.

      @...PROMPT command is preprocessed into __AtPrompt() function during
      compile time.
   $EXAMPLES$
      // display a two line menu with status line at the bottom
      // let the user select favorite day
      SET MESSAGE TO 24 CENTER
      @ 10, 2 PROMPT "Sunday" MESSAGE "This is the 1st item"
      @ 11, 2 PROMPT "Monday" MESSAGE "Now we're on the 2nd item"
      MENU TO nChoice
      DO CASE
      CASE nChoice == 0           // user press Esc key
         QUIT
      CASE nChoice == 1           // user select 1st menu item
         ? "Guess you don't like Mondays"
      CASE nChoice == 2           // user select 2nd menu item
         ? "Just another day for some"
      ENDCASE
   $STATUS$
      R
   $COMPLIANCE$
      C
   $SEEALSO$
      AChoice(), MENU TO, SET MESSAGE, SET INTENSITY, SET WRAP, __MenuTo()
   $END$
 */

/* $DOC$
   $TEMPLATE$
      Function
   $NAME$
      __MenuTo()
   $CATEGORY$
      API
   $SUBCATEGORY$
      User interface
   $ONELINER$
      Invoked a menu defined by set of @...PROMPT
   $SYNTAX$
      __MenuTo( <bBlock>, <cVariable> ) --> nChoice
   $ARGUMENTS$
      <bBlock> is a set/get code block for variable named <cVariable>.

      <cVariable> is a character string that contain the name of the
      variable to hold the menu choices, if this variable does not exist
      a PRIVATE variable with the name <cVariable> would be created to
      hold the result.
   $RETURNS$
      __MenuTo() return the number of select menu item, or 0 if there was
      no item to select from or if the user pressed the Esc key.
   $DESCRIPTION$
      __MenuTo() invoked the menu define by previous __AtPrompt() call
      and display a highlight bar that the user can move to select an
      option from the menu. If <cVariable> does not exist or not visible,
      a PRIVATE variable named <cVariable> is created and hold the current
      menu selection. If there is a variable named <cVariable>, its value
      is used to select the first highlighted item.

      Menu prompts and messages are displayed in current Standard color,
      highlighted bar is displayed using current Enhanced color.

      Pressing the arrow keys move the highlighted bar. When a menu item
      is highlighted the message associated with it is displayed on the
      line specified with SET MESSAGE. If SET WRAP is ON and the user
      press UP arrow while on the first selection the last menu item is
      highlighted, if the user press Down arrow while on the last item,
      the first item is highlighted.

      Following are active keys that handled by __MenuTo():

      <table>
       key            Meaning

       Up             Move to previous item
       Down           Move to next item
       Left           Move to previous item
       Right          Move to next item
       Home           Move to the first item
       End            Move to the last item
       Page-Up        Select menu item, return position
       Page-Down      Select menu item, return position
       Enter          Select menu item, return position
       Esc            Abort selection, return 0
       First letter   Select next menu with the same first letter,
       |              return this item position.
      </table>
      upon exit the cursor is placed at MaxRow() - 1, 0
      __MenuTo() can be nested without loosing the previous prompts.

      MENU TO command is preprocessed into __MenuTo() function during
      compile time.
   $EXAMPLES$
      // display menu item on each screen corner and let user select one
      CLS
      SET MESSAGE TO MaxRow() / 2 CENTER
      SET WRAP ON
      @ 0           , 0             PROMPT "1. Upper left"   MESSAGE " One "
      @ 0           , MaxCol() - 16 PROMPT "2. Upper right"  MESSAGE " Two "
      @ MaxRow() - 1, MaxCol() - 16 PROMPT "3. Bottom right" MESSAGE "Three"
      @ MaxRow() - 1, 0             PROMPT "4. Bottom left"  MESSAGE "Four "
      MENU TO nChoice
      SetPos( MaxRow() / 2, MaxCol() / 2 - 10 )
      IF nChoice == 0
         ?? "Esc was pressed"
      ELSE
         ?? "Selected option is", nChoice
      ENDIF
   $STATUS$
      R
   $COMPLIANCE$
      C
   $FILES$
      Library is core
   $SEEALSO$
      @...PROMPT, AChoice(), SET MESSAGE, SET INTENSITY, SET WRAP, __AtPrompt()
   $END$
 */

/* $DOC$
   $TEMPLATE$
      Command
   $NAME$
      MENU TO
   $CATEGORY$
      API
   $SUBCATEGORY$
      User interface
   $ONELINER$
      Invoked a menu defined by set of @...PROMPT
   $SYNTAX$
      MENU TO <cVariable>
   $ARGUMENTS$
      <cVariable> is a character string that contain the name of the
      variable to hold the menu choices, if this variable does not exist
      a PRIVATE variable with the name <cVariable> would be created to
      hold the result.
   $DESCRIPTION$
      MENU TO invoked the menu define by previous __AtPrompt() call
      and display a highlight bar that the user can move to select an
      option from the menu. If <cVariable> does not exist or not visible,
      a PRIVATE variable named <cVariable> is created and hold the current
      menu selection. If there is a variable named <cVariable>, its value
      is used to select the first highlighted item.

      Menu prompts and messages are displayed in current Standard color,
      highlighted bar is displayed using current Enhanced color.

      Pressing the arrow keys move the highlighted bar. When a menu item
      is highlighted the message associated with it is displayed on the
      line specified with SET MESSAGE. If SET WRAP is ON and the user
      press UP arrow while on the first selection the last menu item is
      highlighted, if the user press Down arrow while on the last item,
      the first item is highlighted.

      Following are active keys that handled by MENU TO:

      <table>
       key            Meaning

       Up             Move to previous item
       Down           Move to next item
       Left           Move to previous item
       Right          Move to next item
       Home           Move to the first item
       End            Move to the last item
       Page-Up        Select menu item, return position
       Page-Down      Select menu item, return position
       Enter          Select menu item, return position
       Esc            Abort selection, return 0
       First letter   Select next menu with the same first letter,
       |              return this item position.
      </table>
      upon exit the cursor is placed at MaxRow() - 1, 0
      MENU TO can be nested without loosing the previous prompts.

      MENU TO command is preprocessed into __MenuTo() function during
      compile time.
   $EXAMPLES$
      // display menu item on each screen corner and let user select one
      CLS
      SET MESSAGE TO MaxRow() / 2 CENTER
      SET WRAP ON
      @ 0           , 0             PROMPT "1. Upper left"   MESSAGE " One "
      @ 0           , MaxCol() - 16 PROMPT "2. Upper right"  MESSAGE " Two "
      @ MaxRow() - 1, MaxCol() - 16 PROMPT "3. Bottom right" MESSAGE "Three"
      @ MaxRow() - 1, 0             PROMPT "4. Bottom left"  MESSAGE "Four "
      MENU TO nChoice
      SetPos( MaxRow() / 2, MaxCol() / 2 - 10 )
      IF nChoice == 0
         ?? "Esc was pressed"
      ELSE
         ?? "Selected option is", nChoice
      ENDIF
   $STATUS$
      R
   $COMPLIANCE$
      C
   $SEEALSO$
      @...PROMPT, AChoice(), SET MESSAGE, SET INTENSITY, SET WRAP, __AtPrompt()
   $END$
 */