I am coming to like this URL matching even more... :) are there any polymorphic lessons to be learnt from other OO languages that might help?

Another thought springs to mind - is there a place for a hierarchy in your interface? It might also assist in despatch efficiency, or even just remind the using programmer to consider despatch efficiency. I don't know if it would have any relevance to handling multi- matching despatches - maybe this is how you specify a multi-despatch?

# flat
/edit?name=(\w+);city=(\w+);... { 
    $r->print "Edit '$name' in '$city'"; 
  }; 

/edit?name=(\w+);job=(.*);... { 
    $r->print "Edit '$name' who does '$job'"; 
  };

# hierarchical1
/edit => [

  name=(\w+);city=(\w+);... { 
    $r->print "Edit '$name' in '$city'"; 
  },

  name=(\w+);job=(.*);... { 
    $r->print "Edit '$name' who does '$job'"; 
  },  

]

# hierarchical2
/edit => [

  name=(\w+);... => [
    
    city=(\w+);... { 
      $r->print "Edit '$name' in '$city'"; 
    },

    job=(.*);... { 
      $r->print "Edit '$name' who does '$job'"; 
    },  
  ],

]

# hierarchical3
/edit => {

  /contact => [
    name=(\w+);city=(\w+);... { 
      $r->print "Edit '$name' in '$city'"; 
    },

    name=(\w+);job=(.*);... { 
      $r->print "Edit '$name' who does '$job'"; 
    },  
  ],

  /basket => [
    
    items=[(\w+)];... { 
      $r->print "Edit items in basket"; 
    },

    delivery=(\w+);... { 
      $r->print "Edit delivery details"; 
    },

  ],

}
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