Implement proper operator precedence.
Implemented post-decrement operator in for incr position.
Implemented '>=' '<=' and '!=' operators.
Fixed a bug in how repeat statements are generated.

Probably introduced a couple more though...
Fixed some issues with pretty printer.
Maintain nesting in pretty printing.
Flatten block statements.

Which leads to nicer pretty printed output.
Distinguish between Expr and Value.
Use template haskell to auto-derive show.