[macker-user] Including external files

[Paul C. <can...@po...>]

A Macker user wrote in to ask if there's a way to include shared  
pattern definitions between rules files.  (Hi Michael!)  There is,  
though it's a bit ugly: use XML external entities.

Create a file -- say "my-patterns.xml" -- next to your rules file.   
Put your shared patterns / rules / whatever in it:

     <var name="basepkg" value="net.innig.macker" />

     <pattern name="macker" class="${basepkg}.**" />

     ..etc..

Then change your rules file so that it starts like this:

     <?xml version="1.0" encoding="UTF-8"?>

     <!DOCTYPE macker PUBLIC
         "-//innig//DTD Macker 0.2//EN"
         "http://innig.net/macker/dtd/macker-0.4.dtd" [

       <!ENTITY myPatterns SYSTEM "my-patterns.xml">
       <!-- you can add more entity declarations here -->

     ]>

     <macker>
     ...etc...

Finally, at the point in your rules file where you want to include  
the shared patterns, do this:

         &myPatterns;

This plops my-patterns.xml straight into your document at that  
location, sort of like an #include in C.

Not pretty, but it does work.  I'm open to suggestions for a simple  
include facility to replace this.

Paul


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"Prediction is hard, especially of the future."  -- Niels Bohr