wml::des::navbar - Navigation Bar

 #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]>

This include file defines a complex navigation bar container tag named CW<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 CW<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 CWtype) prologs and epilogs for the navigation buttons and at least one actual navigation button. Additionally a filter can be applied. The CWnavbar: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 CW<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 CWtxtonly attribute for the textual version, etc.).

Always notice that CW<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 CWnavbar:XXXX tags. The CW<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, CW<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 CW<navbar:button>'s CWurl attribute. Never forget this point!

For complete examples see under CWEXAMPLES below.

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 CW<navbar:debug> and CW<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 CW<navbar:button>'s CWimg 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 CWimgstar 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 CW<navbar:button>'s CWimg 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 CW<navbar:button>'s CWurl 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 CWtarget attribute of CW<navbar:button>. This defines the global header for the navigation bar. Currently there are no attributes used. This defines the global footer for the navigation bar. Currently there are no attributes used. This defines the prolog of CW<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 CWany 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: CWfirst (=1), CWlast (=number of used CW<navbar:button>'s) and CWnext 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: ``CWN'' (normal: used for buttons in normal state), ``CWS'' (selected: used for selected buttons) and ``CWSS'' (sub-selected: used for selected buttons but level is deeper). This type is triggered by the CWselect=CIIDCW and CWsubselected attributes of CW<navbar:render>. This defines the epilog of CW<navbar:button>s, i.e. the local footer for each navigation button. The available attributes or the same as for CW<navbar:prolog>. 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 CW<navbar:render>'s CWselect attribute to mark this button as selected.

alias=STR

The former CWid attribute has to be unique. This tag allows you to group buttons as if they had the same CWid attribute.

txt=STR

The textual representation of the button which is displayed. When no CWalt attribute is specified, it defaults to the value of this CWtxt attribute.

alt=STR

The CWalt attribute for the created CW<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 CWtxt 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: CW#UP#, CW#PREV# and CW#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 (CW.N), selected (CW.S) or subselected (CW.SS) buttons. 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 CWname attribute of CW<navbar:define>.

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 CWtxtcol_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 (CW.N), selected (CW.S) or subselected (CW.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''. 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 CW<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 CW$CFG is the internal configuration structure as seen with CW<navbar:debug> and CW$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>

  <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>

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...

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...

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

 Denis Barbier
 barbier@engelschall.com

 Internal: P1, P2, P3
 External: --

wml(1)