wml::des::navbar(3)						     EN Tools						       wml::des::navbar(3)

NAME

       wml::des::navbar - Navigation Bar

SYNOPSIS

	#use wml::des::navbar

	#   explicitly write javascript code now
	<navbar:jsfuncs>

	#   define a navigation bar
	<navbar:define name=<name> [<options>]>
	    <navbar:header>...</navbar:header>
	    <navbar:footer>...</navbar:footer>
	    <navbar:prolog [<options>]>...</navbar:prolog>
	    <navbar:epilog [<options>]>...</navbar:epilog>
	    <navbar:button id=<id1> txt=... [<options>]>
		 :
	    <navbar:button id=<idN> txt=... [<options>]>
	    <navbar:filter>...</navbar:filter>
	</navbar:define>

	#   debug the internal structure
	<navbar:debug name=<name>>

	#   render the navigation bar
	<navbar:render name=<name> [options]>

DESCRIPTION

       This include file defines a complex navigation bar container tag named "<navbar:define>". It can be used to define navigation bars of any
       optical style by specifying its parts in general and individually and letting the "<navbar:render>" tag create the complete particular HTML
       code.  Creating a navigation bar is a two step process. First you define it according to this grammar:

	  navbar   ::= HEADER{0,1}
		       PROLOG{0,3} BUTTON{1,N} EPILOG{0,3}
		       FOOTER{0,1}
		       FILTER{0,1}

	  HEADER   ::= navbar:header

	  PROLOG   ::= navbar:prolog (type=N)
		     | navbar:prolog (type=S)
		     | navbar:prolog (type=SS)

	  BUTTON   ::= navbar:button

	  EPILOG   ::= navbar:epilog (type=N)
		     | navbar:epilog (type=S)
		     | navbar:epilog (type=SS)

	  FOOTER   ::= navbar:footer

	  FILTER   ::= navbar:filter

       or in other words: navigation bar consists of an optional header and footer, up to three different (according to "type") prologs and
       epilogs for the navigation buttons and at least one actual navigation button.  Additionally a filter can be applied. The "navbar:XXXX"
       names in the above grammar directly correspond to the existing tags you have to use.

       After you have defined such a navigation bar (which is usually done inside an include file) you can create the corresponding HTML markup
       code by placing "<navbar:render>" at the point where this markup code should occur.  This tag can be used more then once when you want (for
       instance inside a page header and its footer or once with graphics and once with the "txtonly" attribute for the textual version, etc.).

       Always notice that "<navbar:render>" has no internal built-in knowledge of your navigation bar except its structure according to the above
       grammar. So, you only receive nice results when you define a nice grammar instance with the available "navbar:XXXX" tags. The
       "<navbar:render>" tag is not there to create nice things you usually couldn't do yourself. It is there to avoid the nasty compilation of
       one million prologs and epilogs for each button where each of these consists of similar HTML code. So, "<navbar:render>" is your workhorse,
       the intelligence is yours.

       But how do we actually get navigation bars? Haven't we forgot something which is essential to navigation bars? Yes, we have. Navigation
       bars feature is that we can define them at one point for the underlaying hyperlink structure and use them at any point inside this
       structure while the hyperlinks are automatically aligned for the current location. But this feature the core of WML already provides
       through its adjustable path variables. So, this include file is useless without this feature. Or in other words: You really have to define
       some root-variable of your structure in a .wmlrc file and then use this variable when defining the hyperlinks inside the
       "<navbar:button>"'s "url" attribute.  Never forget this point!

       For complete examples see under "EXAMPLES" below.

OPTIONS

   Options of "<navbar:define>":
       This defines the navigation bar.

       name=STR
	   This sets the name of the navigation bar which is used both for internal data respresentation and for referencing in "<navbar:debug>"
	   and "<navbar:render>". Always use this attribute (or you risk other navigation bars to be overwritten) and always use a unique name
	   here when using more then one navigation bar.

       imgstar=SPEC
	   This contains a colon-separated list of three strings. They are used for substitution of asterisks in the "<navbar:button>"'s "img"
	   attribute when this attribute only contains one image filename and this filename contains an asterisk. In other words: this single
	   image filename is expanded to a colon-separated list of three image filenames while for each filename the asterisk is substituted with
	   the corresponding string from the "imgstar" attribute.

	   Example:

	     <navbar:define imgstar=std:sel:ovr ...>
	       ...
	       <navbar:button img=button-1-*.gif ...>
	       <navbar:button img=button-2-*.gif ...>
	       ...
	     </navbar:define>

	   This is equivalent to the following:

	     <navbar:define ...>
	       ...
	       <navbar:button img=button-1-std.gif:button-1-sel.gif:button-1-ovr.gif ...>
	       <navbar:button img=button-2-std.gif:button-2-sel.gif:button-2-ovr.gif ...>
	       ...
	     </navbar:define>

       imgbase=PATH
	   Defines a common image base directory, i.e. all non-absolute pathnames in "<navbar:button>"'s "img" attributes are prefixed with PATH.
	   Per default there is no such prefix.

       urlbase=PATH
	   Defines a common navigation base directory, i.e. all non-absolute pathnames in "<navbar:button>"'s "url" attributes are prefixed with
	   PATH. Per default there is no such prefix. Is is useful that PATH itself contains an WML adjustable path variable.

       target=STR
	   The target frame or window to which all hyperlinks are per default redirected to. This can be overwritten by the "target" attribute of
	   "<navbar:button>".

   Options of "<navbar:header>":
       This defines the global header for the navigation bar.  Currently there are no attributes used.

   Options of "<navbar:footer>":
       This defines the global footer for the navigation bar.  Currently there are no attributes used.

   Options of "<navbar:prolog>":
       This defines the prolog of "<navbar:button>"s, i.e.  the local header for each navigation button.

       pos=SPEC
	   This sets the button position where to apply this prolog, i.e.  the number of the button starting with the number 1. Use this to apply
	   a special prolog to a particular button only. The default is "any" for SPEC which means: apply this prolog to any button as long as
	   there is no specially defined one for it.  There are three important special values for SPEC: "first" (=1), "last" (=number of used
	   "<navbar:button>"'s) and "next" which applies to the next button only.

       type=SPEC
	   This sets the type of application of this button. There are three possible values for SPEC: ``"N"'' (normal: used for buttons in normal
	   state), ``"S"'' (selected: used for selected buttons) and ``"SS"'' (sub-selected: used for selected buttons but level is deeper).

	   This type is triggered by the "select=ID" and "subselected" attributes of "<navbar:render>".

   Options of "<navbar:epilog>":
       This defines the epilog of "<navbar:button>"s, i.e.  the local footer for each navigation button. The available attributes or the same as
       for "<navbar:prolog>".

   Options of "<navbar:button>":
       This defines a particular navigation button, i.e. a text or image surrounded by a hyperlink plus a few special features like status bar
       hints and a rollover effect for images.

       id=STR
	   The identification string for this button. This has to be a unique identifier which later is used with "<navbar:render>"'s "select"
	   attribute to mark this button as selected.

       alias=STR
	   The former "id" attribute has to be unique. This tag allows you to group buttons as if they had the same "id" attribute.

       txt=STR
	   The textual representation of the button which is displayed.  When no "alt" attribute is specified, it defaults to the value of this
	   "txt" attribute.

       alt=STR
	   The "alt" attribute for the created "<img>" tags.  When images are not displayed this is used instead by most browsers. If images are
	   displayed this is ignored by most browsers. It defaults to the value of the "txt" attribute.

       img=SPEC
	   The image(s) to display for this button. This can be a single image file or a colon-separated list of three images. The first one is
	   the normal button, the second one is the selected button variant and the third one is the variant which is displayed when the mouse is
	   over the button (but only if the button is not a selected one).

       hint=STR
	   The text displayed in the browsers status bar when the mouse is over the button.

       url=PATH
	   The hyperlink URL which is activated when the button is pressed. There are three special URLs: "#UP#", "#PREV#" and "#NEXT#", which
	   refer to the node one level up, the previous or the next node.

       target=STR
	   A target frame or window where the hyperlink is redirected to.

       menu=STR
	   The name of a navigation bar to insert at this point.

       :a:ATTR=STR :img:ATTR=STR
	   The ``ATTR=STR'' pairs are passed along to the desired HTML tags.  It is also possible to add a prefix to tag name to select only
	   normal (".N"), selected (".S") or subselected (".SS") buttons.

   Options of "<navbar:debug>":
       Use this tag while developing your navigation bar definition.  It dumps the internal structure of this definition.

       name=STR
	   The name of the navigation bar to dump. See the corresponding "name" attribute of "<navbar:define>".

   Options of "<navbar:render>":
       name=STR
	   The name of the navigation bar definition to use when rendering.

       select=ID
	   Select a particular button as selected.

       subselected
	   Marks the selected button as a subselected one, i.e. the current page for which the button is selected is deeper than the original page
	   for which this button stands.

       txtcol_select=#rrggbb
	   This is a hack because of the HTML rendering of typical browsers on anchors.  You have to use this attribute when you want to create
	   textual navigations bars with specific colors, this can not be performed with prologs and epilogs when defining navbars.

       txtcol_normal=#rrggbb
	   This is the corresponding tag to "txtcol_select" because we want to have a homogen configuration style.

       menumode=inner|outer
	   With menumode=inner (default), a selected sub-menu is inserted before epilog of current entry, otherwise it is put after.

       txtonly
	   Forces the rendering to ignore all defined images.

       nohints
	   Do not create Javascript hints for navigation buttons.

       :a:ATTR=STR :img:ATTR=STR
	   The ``ATTR=STR'' pairs are passed along to all the desired HTML tags found in this navbar.  It is also possible to add a prefix to tag
	   name to select only normal (".N"), selected (".S") or subselected (".SS") buttons.  For instance with

	      <navbar:render name=main :img:class=nav
		 :a.N:class=nav-n :a.S:class=nav-s :a.SS:class=nav-ss />

	   attribute ``class="nav"'' is added to all images, ``class="nav-s"'' is added to anchor when button is selected (this is a dummy
	   example, since when button is selected, there is no such anchor), ``class="nav-ss"'' is added when button is subselected, and normal
	   links have ``class="nav-n"''.

   Options of "<navbar:filter>":
       This defines the body of a Perl filtering function which can be used to post-process the generated HTML markup code before it is written
       out.  Currently there are no attributes used.

       When no "<navbar:filter>" tag is specified, no such filtering occurs. When

	 <navbar:filter> BODY </navbar:filter>

       is specified, internally an anonymous Perl function is created and the HTML markup code is filtered through this function as follows:

	 $func = sub { BODY };
	 $markup_code = &{$func}($markup_code, $CFG, $select);

       where $CFG is the internal configuration structure as seen with "<navbar:debug>" and $markup_code is a literal string holding the HTML
       markup code. In other words, when you want to apply a filter, you have to do it with the following skeleton:

	 <navbar:filter>
	     my ($mcode, $CFG, $select) = @_;
	     ...
	     return $mcode;
	 </navbar:filter>

   Options of "<navbar:jsfuncs>":
       This prints Javascript functions used for rollover effects on images.  This macro discards itself after first invocation so that
       definitions are printed only once.  It is automatically called by "<navbar:render>", so it could looks useless.	But if you consider

	 <en><navbar:render name=main></en>
	 <fr><navbar:render name=main></fr>

       javascript code only appears in English version.  The correct solution is to put this tag outside of any slice:

	 <navbar:jsfuncs>
	 <en><navbar:render name=main></en>
	 <fr><navbar:render name=main></fr>

EXAMPLES

   Classic Navigation bar
       File: nb.inc

	 <navbar:define name=test
		 imgbase="img/" urlbase="$(ROOT)"
		 txtcol_normal="#000000" txtcol_select="#ffffff">
	   <navbar:header>
	     <table cellspacing=1 cellpadding=2 border=0>
	     <tr>
	   </navbar:header>

	   <navbar:prolog>	  <td bgcolor="#cccccc"> </navbar:prolog>
	   <navbar:prolog type=S> <td bgcolor="#cc3333"> </navbar:prolog>

	   <navbar:button id=foo txt="Foo" url="foo.html" hint="The Foo Page">
	   <navbar:button id=bar txt="Bar" url="bar.html" hint="The Bar Page">
	   <navbar:button id=baz txt="Baz" url="baz.html" hint="The Baz Page">

	   <navbar:epilog> </td> </navbar:epilog>

	   <navbar:footer>
	     </tr>
	     </table>
	   </navbar:footer>
	 </navbar:define>

	 <navbar:render name=$(name) select=$(select)>

       File: .wmlrc

	 -DROOT~.
	 -I.

       File: foo.wml

	 #use wml::std::page
	 #use wml::des::navbar

	 <page indent=2>

	 #include "nb.inc" name=test select=foo

	 <h1>The Foo Page</h1>
	 <p>
	 Foo...

       File: bar.wml

	 #use wml::std::page
	 #use wml::des::navbar

	 <page indent=2>

	 #include "nb.inc" name=test select=bar

	 <h1>The Bar Page</h1>
	 <p>
	 Bar...

   Nested Navigation bar
       File: nb.inc

	 <navbar:define
		 name=test imgbase="img/"
		 txtcol_normal="#000000" txtcol_select="#ffffff">
	   <navbar:header>
	     <ul>
	   </navbar:header>
	   <navbar:prolog><li></navbar:prolog>

	   <navbar:button id=foo txt="Foo" url="foo.html">
	   <navbar:button id=bar txt="Bar" url="bar.html" menu="nb-bar">

	   <navbar:footer>
	     </ul>
	   </navbar:footer>
	 </navbar:define>
	 <navbar:define name="nb-bar">
	   <navbar:header>
	     <ul>
	   </navbar:header>
	   <navbar:prolog><li></navbar:prolog>

	   <navbar:button txt="First bar item">
	   <navbar:button txt="Second bar item">

	   <navbar:footer>
	     </ul>
	   </navbar:footer>
	 </navbar:define>

	 <navbar:render name=test select=$(select)>

       File: foo.wml

	 #use wml::std::page
	 #use wml::des::navbar

	 <page indent=2>

	 #include 'nb.inc' select=foo

	 <h1>The Foo Page</h1>
	 <p>
	 Foo...

       File: bar.wml

	 #use wml::std::page
	 #use wml::des::navbar

	 <page indent=2>

	 #include 'nb.inc' select=bar

	 <h1>The Bar Page</h1>
	 <p>
	 Bar...

AUTHORS

	Ralf S. Engelschall
	rse@engelschall.com
	www.engelschall.com

	Denis Barbier
	barbier@engelschall.com

REQUIRES

	Internal: P1, P2, P3
	External: --

SEE ALSO

       wml(1)

EN Tools							    2014-04-16						       wml::des::navbar(3)