what types of join are supported other than inner ?

[godv2]

package main

import (
	"github.com/k0kubun/pp"

	"github.com/araddon/qlbridge/rel"
)

func main() {

	qstr := `SELECT authors.author_name, authors.author_email, author_submissions.article_title FROM authors
	LEFT JOIN author_submissions ON authors.author_email=author_submissions.author_email`

	stmt, err := rel.ParseSqlSelect(qstr)
	handlerErr(err)

	pp.Println(stmt)
}

func handlerErr(err error) {
	if err != nil {
		panic(err)
	}
}

this gives error unexpected token Got Token{ LEFT Type:"identity" Line:2 Col:5 Q: Pos:101} near: T JOIN author_submi