Ideas
~~~~~
"Optimization" encompasses:
  - substitution informed by equational reasoning (about states)
  - removal of redundant code, as justified by reasoning about
    continuations

"Code motion" is achieved by inserting redundant code,
thereby making original code redundant, which in turn
can be removed.

Technique
~~~~~~~~~
No single technique; the secret sauce is how we combine things:
  - Zipper CFG
  - Disctinct representations for construction and analyis of CFGs
  - Maximum use of polymorphism
  - Type classes to make notation resemble prior art
  - Transfer equations coded in dragon-book style
  - Fixed points courtesy Lerner, Grove, and Chambers (2002)

Contribution
~~~~~~~~~~~~
We make dataflow optimization easy to think about and easy to build:

 * Ideas that reconcile the ad-hoc 'optimization zoo' found in the
   dragon book with methods of reasoning long understood by functional
   programmers.

 * Design and implementation that make it not just possible but *easy*
   to use dataflow techniques in your compiler.



---------------------------------
Working title: Dataflow Optimization Made Simple

Note: By decomposing 'optimizations' into smaller units, we simplify.
'induction-variable elimination' is *not* an atomic thing!


---------------------------------
Vague Outline
1. Intro
2. Short example
3. Logical view of optimization
4. Clients (examples, including type class declarations)
5. Graphs
6. Fixed-point computation; the dataflow monad
7. Discussion