abstract code: get it to the stage where a "rubbish" concrete version builds

Signed-off-by: Peter Williams <pwil3058@gmail.com>
abstract code: examine implementation options for generated table design

Signed-off-by: Peter Williams <pwil3058@gmail.com>
abstract code: pass the buck on lexical failure
This will give the user a chance to handle this problem themselves.
We should be able to detect at table generation time whether they have done so
and if not do something generic.

Signed-off-by: Peter Williams <pwil3058@gmail.com>