kkallio@6: (* NAVBAR provides services to construct and pretty print to xml typical
kkallio@6:  * menu items (of a visible text and a url link) and menu bars assembled
kkallio@6:  * from them.  It is intended to be used as a low-level component in
kkallio@6:  * constructing navigation related widgets and theme parts. *)
kkallio@6: 
kkallio@6: type navItem
kkallio@6: (* Items in the navigation menu. *)
kkallio@6: 
kkallio@6: con navBar :: Type -> Type
kkallio@6: (* A menu bar of navigation links. Up to one link may be active. *)
kkallio@6: 
kkallio@6: type build
kkallio@6: type print
kkallio@6: (* These track the current navbar mode. *)
kkallio@6: 
kkallio@6: class mode
kkallio@6: (* To make sure we always print the navbar correctly. *)
kkallio@6: 
kkallio@6: val navToXml_build : mode build
kkallio@6: val navToXml_print : mode print
kkallio@6: (* How to print both modes. *)
kkallio@6: 
kkallio@6: val printingNavBar : navBar build -> navBar print
kkallio@6: (* This switches the navbar from building mode to printing mode.  Normally not
kkallio@6:  * necessary to call this, but is in the signature in case the programmer will
kkallio@6:  * pass the same navbar to several components wanting to print it.  Then by
kkallio@6:  * using this first multiple (redundant) calls to List.rev can be avoided.
kkallio@6:  * Mode tracking makes this optimization safe. *)
kkallio@6: 
kkallio@6: val emptyNavBar : navBar build
kkallio@6: (* An empty menu bar. *)
kkallio@6: 
kkallio@6: val mkNavItem : string -> url -> navItem
kkallio@6: (* Make a menu item with visible text given by the string and linking to url. *)
kkallio@6: 
kkallio@6: val navAdd : navItem -> navBar build -> navBar build
kkallio@6: (* Add an unactive item to the right end of the navbar. *)
kkallio@6: 
kkallio@6: val navAddActive : navItem -> navBar build -> navBar build
kkallio@6: (* Add an active item to the right end of the navbar.  If there already
kkallio@6:  * was an active item it will be deactivated. *)
kkallio@6: 
kkallio@6: val navItemToXml : option css_class -> navItem -> xbody
kkallio@6: (* Pretty print a navItem with an optional style to a piece of <a>...</a> xml. *)
kkallio@6: 
kkallio@6: val navBarToXml : t ::: Type -> mode t -> navBar t -> xbody
kkallio@6: (* Pretty print the navigation menu as a piece of xml made of
kkallio@6:  * a chain <li><a>...</a></li> repeated. *)
kkallio@6: 
kkallio@6: style active
kkallio@6: style last
kkallio@6: (* CSS classes to mark the active and last menu item. *)