Each layer in turn extracts its header from a tuple and passes the remaining headers up to the layer above.
The virtual projections associated with the reified virtual tuple have also been reified as real projections.
Both categories can be further refined in an ontology of semantic tuple types.
Variables and base type constants are passed through unchanged and, for a tuple, the translation rebuilds the tuple with the translated values.
The translation of a tuple that contains non-values threads the compile-time information through the evaluation from left to right.
Then, tuple centres can be conceived as general-purpose coordination artifacts, which can be customized (programmed, tuned) dynamically to entail a specific coordinating behaviour.
The idea, of course, is that the calling convention for a function that returns an unboxed tuple arranges to return the components in registers.
The first argument of the tuple matches the category of the first daughter of the indexed rules.
