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    AslRequest -- get input from user for an ASL requester (V36)

    BOOL result = AslRequest( request, ptags );
    D0                        A0       A1

    BOOL    result;
    APTR    request;
    struct TagItem       *ptags;

    Prompts the user for input, based on the specific type of
    requester and modifying tagitems.  The actions and results
    are specific to the type but in general the action is to open
    a requesting window prompting the user for a specific input.
    If the user cancels or the system aborts the request, NULL
    is returned, otherwise the request data structure readable
    data reflects the user input.
    Note that tag values stay in effect for each use of the
    requester until they are cleared or modified by passing the
    same tag with a new value.

    request = requester structure allocated with AllocAslRequest().
    ptags = pointer to an array of TagItems which may be used to
        modify the requester.

    AslRequestTags( type, tags... ) which accepts your tags
    on the stack, is available in amiga.lib.

    Example Usage: AslRequestTags( ASL_FileRequest,
                                   ASL_Hail, "My Title Bar",
                                   TAG_DONE );


      TAGITEMS !!! )

    ASL_Hail (STRPTR) - Hailing text to prompt user, typically
        displayed in window title bar.
    ASL_Window (struct Window *) - Parent window for the request
        function, which is used to select the screen on which the
        requesting window will be displayed and also is used for
        a shared IDCMP port.

    ASL_LeftEdge (WORD) - Preferred display position for left edge where
        request window should open.
    ASL_TopEdge (WORD) - Preferred top edge of request window.
    ASL_Width (WORD)   - Preferred width of request window.
    ASL_Height (WORD)  - Preferred height of request window.

    ASL_HookFunc (APTR) - Pointer to callback function, specific to
        each AslRequest type.

    ASL_File (STRPTR) - FileRequester initial filename string.
    ASL_Dir (STRPTR) - FileRequester initial directory path string.

    ASL_FontName (STRPTR) - FontRequester initial fontname string.
    ASL_FontHeight (UWORD) - FontRequester initial height (ta_YSize).
    ASL_FontStyles (UBYTE) - FontRequester initial styles (ta_Style).
    ASL_FontFlags (UBYTE) - FontRequester initial flags (ta_Flags).
    ASL_FrontPen (BYTE) - FontRequester front pen color (fo_FrontPen).
    ASL_BackPen (BYTE) - FontRequester back pen color (fo_BackPen).
    ASL_MinHeight (UWORD) - Minimum height for FontRequester display
        of font sizes.  (Application must check return value).
    ASL_MaxHeight (UWORD) - Maximum height for FontRequester display
        of font sizes. (Application must check ta_YSize returned).

    ASL_OKText (STRPTR) - Replacement for default "OK" gadget text.
        ( Limited to approx. six characters ).
    ASL_CancelText (STRPTR) - Replacement for default "CANCEL"
        gadget text. ( Limited to approx. six characters ).

    ASL_FuncFlags (ULONG) - Function flags, depends on requester
        type.  Example: FILF_SAVE for FileRequester.
    ASL_ExtFlags1 (ULONG) - Extended flags (to pass FILF1_ bitdefs)
               Example: FIL1F_NOFILES for file requester

    If NULL, typically the user cancelled the requester or a system
    failure prevented the requester from being opened.  If non-zero,
    values will be set depending on the particular type of request,
    in the requesting data structure.  See "libraries/asl.h" for
    information on the READ-ONLY fields in each specific type of


    Asl provides a way for applications to interact with requester
    operation via a callback (hook) function.  For the ASL file and
    font requesters, there are two ASL_FuncFlags to specify that you
    want a callback:

         for FileRequester: FILF_DOWILDFUNC and FILF_DOMSGFUNC
         for FontRequester: FONF_DOWILDFUNC and FONF_DOMSGFUNC

    The DOWILDFUNC allows you to perform the pattern matching.
    The DOMSGFUNC allows you to handle IDCMP messages received
    for windows that are sharing a UserPort with the requester.

    If you set one or both of these flags via the ASL_FuncFlags
    tagitem, you must provide a pointer to your hook function
    using the ASL_HookFunc tagitem.  Your function will be called
    as follows:

     ULONG rf_Function(ULONG Mask, CPTR Object, CPTR AslRequester)

    The Mask value is a copy of the specific ASL_FuncFlag value
    the callback is for.  Object is a pointer to a data object
    specific to the reason for the callback (defined by Mask).
    AslRequester is a pointer to the requester structure.

    Note that you can only define one HookFunc per requester.
    Your hook function must examine the Mask passed to it to
    determine what the callback is for and what the Object is.

    The following table will explain what is passed to, and
    expected to be returned by a hook functions for various masks:

    FileRequester DOWILDFUNC
    Purpose: to accept or reject individual files for display list
    Inputs: Mask            = FILF_DOWILDFUNC
            Object          = struct AnchorPath *
            AslRequester    = struct FileRequester *
    Result: You return zero to accept file for display in list

    FontRequester DOWILDFUNC
    Purpose: to accept or reject individual fonts for display list
    Inputs: Mask            = FONF_DOWILDFUNC
            Object          = struct TextAttr *
            AslRequester    = struct FontRequester *
    Result: You return non-zero to accept font for display in list

    FileRequester (or FontRequester) DOMSGFUNC
    Purpose: to handle IDCMP msgs for other windows sharing port
    Inputs: Mask            = FILF_DOMSGFUNC (FONF_DOMSGFUNC)
            Object          = struct IntuiMessage *
            AslRequester    = struct FileRequester (FontRequester) *
    Result: You must return the Object pointer (asl will Reply the Object)

    AllocAslRequest(), FreeAslRequest()

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