Bumped into this randomly. We do correctly parse escape sequence, but
the format would simply but the unescaped string back on save. Now it
properly re-escapes strings before flushing them back. I also removed
the escape sequence for 'backspace' and 'new page' form feed as I
don't see any use case for those in an Aiken program really...
We do not actually every parse negative values in there, as a negative value is a combination of a 'Negate' and 'UInt' expression.
However, for patterns and constant, it'll be simpler to parse whole Int values as there's no ambiguity with arithmetic operations
there. To avoid confusion of having some 'Int' constructors containing only non-negative values, and some being on the whole range,
I've renamed the constructor to 'UInt' to make this more obvious.
This was a bit more tricky than anticipated but played out nicely in
the end. Now we have one holistic way of parsing todos and errors
instead of it being duplicated between when/clause and sequence. The
error/todo parser has been moved up to the expression part rather than
being managed when parsing sequences. Not sure what motivated that to
begin with.
Fixes#621.
KtorZ