[DAS2] Re: feature filter examples

[Andrew Dalke]

Another confusing situation.  Is the following allowed

   att=name:Andrew,lang:en

to mean
    attribute name contains "Andrew" OR
    attribute lang contains "en"

This appears to be legal under the current spec because

     Within the URL query string, multiple criterion=value
     pairs are ANDED together:
        ...
     To describe OR relationships, you may separate filter
     values by commas.

In my above example the "criterion" is "att" (because it's
to the left of the "=") and the "value" is
   "name:Andrew,lang:en"
which is made of two value fields
   "name:Andrew" "lang:en"

Note though that that means

   att=name:Andrew,lang:en

does not mean to find

   attribute "name" contains "Andrew" OR
   attribute "name" contains "lang:en"

Nor is it
   attribute "name" contains "Andrew" OR
   attribute "name" contains "lang"
   SYNTAX ERROR - ':' not allowed at this point

It also means that

   att=name:Andrew,Gregg

IS NOT legal, because "Gregg" is not a valid value
for the "att" criterion.


				Andrew
				dalke at dalkescientific.com