[Pmwiki-users] Re: new directive tag syntax (was: Pmwiki new version)

[Patrick R. Michaud]

On Thu, Jun 10, 2004 at 08:02:07AM -0700, Wayne Lee wrote:
> 
> why have separate syntax for values
> and directives?

I think the biggest reason is that values sometimes need to appear
within a directive, and the separate syntax becomes easier to read.
For example, I think it's much easier for people to read and parse

   [:search {$Group}/ text:]

than it is to read

   [:search [:group:]/ text:]
   {{search {{group}}/ text}}
   (.search (.group.)/ text.)

but perhaps that's just my quirkiness.  I'll also note that the
possibility of nested directives with the same syntax can make the 
programming side of things *much* more complicated -- not only for me 
but also for anyone who wants to add new directives to PmWiki 
(e.g. in a Cookbook module).  The fact that this makes the programming
more complex doesn't mean it shouldn't be done, but it is a consideration
for people who would like to customize things later.

To me a value and a directive are slightly different--a directive usually
implies we want to perform (or suppress) some action, whereas a value
is just a simple text substitution.  Again, I'll go back to the notion
of title--I think we need both a directive to set a page's title as well
as a way of displaying the page's title in the output.  To me this
implies different markup

   [:title my page's title:]  -- set the title for the page
   {$Title}                   -- substitute page's title here

although that doesn't have to be the case

   [:settitle my page's title:]
   [:title:]                

> the '$' can be replaced by an internationally
> acceptable letter that easy to type after the '['.
> the original colon at the end of the directive
> (e.g. [:noheader:]) is an extra letter to type,
> and an extra letter to type in error, that IMO
> doesn't buy much.

The extra character at the end of the directive buys a *lot*, namely, the
ability to include a closing bracket in a parameter.  If we go with
[$directive param], then there's not an easy way for "param" to contain
a closing bracket.

Pm