A Gentle Introduction to SequenceL: The Taurus, Windows, and Computer Languages

Dr. Daniel E. Cooke

In this talk we will review the SequenceL Language abstraction and new results in the language design resulting from our six month effort with Guidance, Navigation, and Control Engineers at NASA's Johnson Space Center.

From a very small language, the audience will see the use of SequenceL-MildForm, a pure and simple functional language; the gradual removal of the need for recursion based upon SequenceL-WhiledForm; the further elimination of recursion as a result of the Normalize-Transpose; and the abstraction improvement recently obtained that allows for polynomial time backtracking.

Specifically we will review:

  1. The SequenceL semantics of Consume-Simplify-Produce coupled with Normalize-Transpose (CSP-NT),
  2. The addition of free variables,
  3. How CSP-NT is used to implement all language constructs beyond basic built-in operations,
  4. An outline of current runtime performance results.
  5. Preliminary results in Auto-coding.

The resulting language is a small, Turing Complete Language that has no assignment or Input-Output, making proofs correctness easy to produce, and a language in which the user can declare data products with a significant reduction in the need to also provide the iterative/recursive algorithmic structures to process or produce them.