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Query

  Query enables one to set all the dynamic context states to the node and path given as arguments, and then inherit from it. The query context (i.e., the node and path originally supplied as a query) is not dynamic, and so is unaffected by this inheritance specification.

In standard DATR, the dynamic contexts are the global and local contexts, so Query:<'Foo' a b> sets the global context to Foo:<a b> and then inherits from Foo:<a b>.

Query is functionally equivalent to Global, and so probably not as useful as its relatives, QueryNode and QueryPath . However, if one introduced additional dynamic contexts (for example, reified as additional library functions such as Universal), then Query should reset those contexts as well.


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Copyright © Roger Evans, Gerald Gazdar & Bill Keller, Tuesday 10 November 1998