Missed comment from previous code review.
Next up: execution tests so this won't happen again
LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/134480043
Improve the generated code by using a const instead of a var for the names string.
This requires some refactoring to get neat const() and var() blocks.
Also change the generate map code go use a single sliced string, to reduce the
size of the compiled representation (only one string value).
LGTM=gri
R=gri
CC=golang-codereviews
https://golang.org/cl/135450044
Refactor a little to make testing easier.
Add golden tests and a check fo splitIntoRuns, which is the subtlest piece.
Still to come: execution tests.
Also fix a few issues in the generated code.
LGTM=gri
R=gri
CC=golang-codereviews, josharian
https://golang.org/cl/134450044