Re: [htmltmpl] MARK= enhancement to the HTML::Template LOOP construct

[Mathew R. <mat...@re...>]

My local copy of H::T is modified so that a) you can create custom =
TMPL_xxx tags, and b) you can create custom ESCAPE tags by overloading a =
H::T::Escape (I have factured out that functionality into seperate =
modules).

I'd be interested to how you did this MARK stuff - I have previously =
used H::T::Expr to generate custom layouts, although I consider this =
solution to be rather hack'ish since I tend to think that TMPL_LOOP's =
need not always loop from start to finish of Perl array.

regards,
Mathew

  ----- Original Message -----=20
  From: Bob Diss=20
  To: htm...@li...=20
  Sent: Wednesday, October 06, 2004 10:31 PM
  Subject: [htmltmpl] MARK=3D enhancement to the HTML::Template LOOP =
construct


  Greetings everyone!  I've been using HTML::Template on my site for =
several years now, and I'm really pleased with what it can do and how =
easy it is to teach my HTML'ers.  I'd like to share with you some =
enhancements I've done to make it even more powerful (for me, at least).

  I make heavy use of the <TMPL_LOOP> tag on my site.  However, I seem =
to always want to do something that's hard.  For example, I want to =
layout the loop items in three columns (instead of two using the __ODD__ =
tag).  Or, I want to layout just the first 5 items and (if there are =
more) make a link to "see more".  Or, I want to lay items in 4 balanced =
columns (i.e. A-G arranged vertically in the first column, H-N in the =
second, O-U in the third, V-Z in the last).

  To accomplish this, I implemented a "MARK=3Dsome-value" tag for the =
<TMPL_LOOP> construct.  This MARK tag requests that the additional loop =
context variables __MARK__, __MARKFIRST__, and __MARKLAST__ be set.  =
There are four possible formats for the MARK value.

  If I say "MARK=3D3" then the first item and every third item =
thereafter will have __MARK__ set to true (i.e. it will be true for =
items 1, 4, 7, 10, etc.).  __MARKFIRST__ is set true whenever __MARK__ =
is true, and __MARKLAST__ is set true for the last item before __MARK__ =
is true (i.e. items 3, 6, 9, etc.).  With this I can easily setup =
N-column displays in HTML by triggering my <TR> starts and ends with =
__MARKFIRST__ and __MARKLAST__.

  If I say "MARK=3D-6" then all the items before item 6 (items 1 through =
5) will be __MARK__'ed true.  The first item will be __MARKFIRST__, and =
the 5th item (or the last item if there are less than 6 items) will be =
__MARKLAST__.  This helps me process a list of items when I just want to =
show the first N, but want to be smart enough to know if there are more =
items to talk about.  Since the <TMPL_LOOP> iterates over all the items, =
I can trap the __LAST__ item and check to see if it was __MARK__'ed.  If =
so, I can offer a "more" link.

  Of course, there's a complimentary "MARK=3D+5" option to mark the =
items that occur after item 5 (items 6 on).

  Finally, the hardest thing to do is layout balanced columns.  To do =
this I specify "MARK=3DTOTGRP/GRP", as in "MARK=3D3/2".  This tells the =
loop to divide the items in to TOTGRP balanced groupings (three in this =
case), and __MARK__ the items in the GRP grouping (two in this case).  =
For example: I often have a list of alphabetized names, and I want to =
show them in a way that people are used to, which is to have them =
vertically alphabetized, and split into N balanced columns.  Using this =
tag my HTML becomes something like this:

  <TABLE><TR VALIGN=3D"TOP">

  <TD>
  <TMPL_LOOP NAME=3D"foo" MARK=3D"3/1">
  <TMPL_IF __MARK__> output an item in column 1<BR></TMPL_IF>
  </TMPL_LOOP>
  </TD>=20

  <TD>
  <TMPL_LOOP NAME=3D"foo" MARK=3D"3/2">
  <TMPL_IF __MARK__> output an item in column 2 <BR></TMPL_IF>
  </TMPL_LOOP>
  </TD>=20

  <TD>
  <TMPL_LOOP NAME=3D"foo" MARK=3D"3/3">
  <TMPL_IF __MARK__> output an item in column 3 <BR></TMPL_IF>
  </TMPL_LOOP>
  </TD>

  </TR></TABLE>

  I've found these enhancements to be very useful, as they save me from =
coding layout decision flags in my loop items, while enabling more =
sophisticated layout possibilities.

  Comments?  Thoughts?  Suggestions?  It works for me -- would it work =
for anyone else?

  -Bob Diss



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