Added CREATE PROCEDURE & FUNCTION

[Hydrocharged]

This adds:

CREATE PROCEDURE
SHOW PROCEDURE STATUS
SHOW FUNCTION STATUS
DROP PROCEDURE
CALL

The SHOW...CODE statements are being skipped for now, as they're relatively unused compared to the above statements. Additionally, the CREATE statements do not have a fully fleshed-out routine body, as we currently do not parse all valid statements anyway.

[Hydrocharged]

The conflicts: 24 shift/reduce is not something that I know how to fix, nor am I too sure what's going on. Googling shows it deals with precedence, but it wasn't helping out too much. If it's deemed critical I can spend more time trying to fix it.
Removed CREATE FUNCTION for now to remove this issue.

[zachmu]

Sadly you do need to deal with the shift/reduce conflicts. They're a pain, but you can't actually guarantee a correct parse unless you eliminate them.

The way to debug them is to examine the .output file when you run goyacc.

goyacc -o sql.go sql.y

Produces a log called y.output. If you search it for shift/reduce you can get clues on where the conflict is coming from.

These conflicts happen when the grammar has ambiguity, so when there is a place in the input where two different different rules could be applied next. Can't have it. The most common approach to eliminating these is to combine multiple rules into one to eliminate the ambiguity, which you can see was done various places in the grammar (read the comments).

[zachmu]

This all looks pretty reasonable, nice work. I'll take another look when you sort out the conflicts in the grammar.

[zachmu]

Do you actually want the skips on these? Typically those are for unsupported / semi-supported features

[Hydrocharged]

We don't support the CODE ones for now, which are different than the STATUS ones. We probably won't ever support the CODE ones tbh. They return something that looks like some kind of MySQL IL.

[zachmu]

LGTM!