Re: custom non-atomic steps?

On 19 July 2013 21:07, Geert Josten wrote:

  Hi,

> It really is much alike higher order functions, perhaps just
> more than you realized..

  That claim does not help to see how it would.  As far as I
understand, the discussed use case is to be able to declare the step
my:if so the following:

    <my:if test="...">
       <px:xpath-context .../>
       [ sub-pipeline ]
    </my:if>

is equivalent to:

    <p:choose>
       <p:when test="...">
          <px:xpath-context .../>
          [ sub-pipeline ]
       </p:when>
       <p:otherwise>
          <p:identity/>
       </p:otherwise>
    </p:choose>

  This is a macro definition.  Like the powerful 'defmacro' in Lisp.
Function items give the ability to call a step using a dynamic
reference, rather than a static name, and to pass those references
around.

  I think this macro feature would be a very convenient feature.  And
could help fighting the verbosity of the language: if you find
yourself using all the time the same constructs (like the "if then
something else identity" above), then you can improve the language
yourself...

  Regards,

-- 
Florent Georges
http://fgeorges.org/
http://h2oconsulting.be/

Received on Sunday, 21 July 2013 11:24:50 UTC