[WIP] Parser return lifts

[masonedmison]

Problem

As part of discussions with @deusaquilus, he pointed out that "lifts" can be gotten from the parser instead of calling ExtractLifts. Calling ExtractLifts ends up being quite an expensive operation.

Solution

Within the quote macro, "lifts" are gotten from the parser instead of by executing ExtractLifts.

Checklist

• Unit test all changes*
• Update README.md if applicable
• Add [WIP] to the pull request title if it's work in progress
• Squash commits that aren't meaningful changes
• Run changes made to existing tests by @deusaquilus
• Run JProfiler against the compilation of quill-sql-tests and compare with a previous run
  in which lifts are gotten from ExtractLifts in the quote macro.

*: I believe the existing tests should cover all of the cases to test.

@getquill/maintainers

[masonedmison]

If I understand correctly how q is evaluated, where q is

        val q = quote {
          sql"#$a || ${lift("foo")}".as[String]
        }

then

• The "lift" macro fires first which returns EagerPlanter("foo", ...).unquote
• Quote macro is called which passes '{EagerPlanter("foo").unquote} to the parser
• QuotationParser fires first on UprootableUnquote where expr is
  EagerPlanter("foo") and adds EagerPlanter("foo") to Lifts.lifts
• InfixParser then fires, as part of parsing ExtractLifts is called which gets the
  "foo" lift.

which, given that we are now "getting" lifts from the parser, makes sense the EagerPlanter("foo") would be now included in the lifts of the returned Quoted.

It's not clear to me, though, if this will yield any difference in behavior. I have a TODO for this.

[deusaquilus]

This logic sounds right. The actual EagerPlanter(foo) is supposed to live inside the QuotationVase. I don’t think the ExtractLifts inside InfixParser is even necessary anymore and you should try to remove it.

[masonedmison]

I don’t think the ExtractLifts inside InfixParser is even necessary anymore and you should try to remove it.

I'll start looking into this

[masonedmison]

@deusaquilus Indeed, you are right; simply getting the "lifts" and "pluckableUnquotes" from the Lifts context after parsing the Params seems to work: all of the tests with InfixTest pass.

Just pushed up a commit with this change.

[masonedmison]

TODO @masonedmison I still need to convince myself that this is a sound change

[deusaquilus]

Looks alright to me. We can talk about it when I’m back in a couple days.