Smart evolutions statements parsing

[Vadim V. Kh.]

Hello!

Quoting myself and some other user from play github about being forced to escape semicolons by doubling:

https://github.com/playframework/playframework/issues/6765#issuecomment-405314087


"...this is extremely painful while working with Postgres stored procedures.
You have to manually escape/unescape a body of a procedure or run some silly scripts
while copying a procedure code from a migration file and a database IDE/REPL back and forth
(a double semicolon in a procedure body produces an empty statement which is disallowed in pl/pgsql)..."


https://github.com/playframework/playframework/pull/649#issuecomment-112556094


"For example with plpgsql I have to use semicolons in a procedure declaration.
It's annoying to escape it by entering one more.
And I have to remove it to run the same script in pgAdmin or IntelliJ."


A change is proposed: keep requiring escaping semicolons by doubling for backward compatibility,
but add some configuration switch (like play.evolutions.smartStatementParsing = true)
that turns on the smart statements separator aware of comments/string literals.

Right now the whole statements parsing is an one-line expression.
I want to create a bit more sophisticated parser that however aids user experience as described above.
Is it worth efforts? Is it going to be accepted if done right?