cleaning

typechecking support for a few more contexts for expressions (e.g. on
expressions in joins, check expressions, wheres in updates and
deletes, etc.)
type checking support for a few more statement types
work on implicit casts
improvements to checksource command
prototype idea for extension system
hack to improve typechecking of function bodies - they are now type
checked after the whole rest of the file
lots of work on catalog typechecking

main internal changes:
lots of refactoring
heavy rearrangement of ag code, it's not a complete mess anymore
split local binding code from catalog code

environment

New environment data type with abstracted implementation, can now
process ddl in a script and type check against it. Some work on
variable scoping, and annotations. New commands: annotateSource (adds
some annotations for statements into the original source code as
comments), and checksource, which outputs type errors in emacs
friendly format.

annotated tree

The API and type checking code has had a major overhaul, now uses
annotations inline in the ast, has rudimentary haddock documentation,
and the API is starting to take shape. No significant progress on
actual parsing or typechecking since last release.

secondtypechecking

typechecks a fair amount of select statements, and does some type
checking of insert, update, delete and create statements. It can also
take a sql file and parse, type check, and spit it back out with type
checking information interspersed with the statements (but with the
formatting mangled and the comments stripped).


earlytypechecking

hasn't fixed the error messages, but can now type check some select
statements, it includes a command to read a sql file in, type check it
against a database, then pretty print the ast interspersed with the
inferred types of each statement in comments.


lexing

parses with a separate lexer, unfortunately the error messages have
gone wrong.


prealpha1

parses without a separate lexer and gives ok error messages