You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: parser.go
    path of file: ./repos/ferret/pkg/parser
    
    the code of the file until where you have to start completion: //go:generate antlr -Xexact-output-dir -o fql -package fql -visitor -Dlanguage=Go antlr/FqlLexer.g4 antlr/FqlParser.g4
package parser

import (
	"github.com/antlr/antlr4/runtime/Go/antlr/v4"

	"github.com/MontFerret/ferret/pkg/parser/fql"
)

type Parser struct {
	tree *fql.FqlParser
}

func New(query string) *Parser {
	inpu
    
func New(query string) *Parser {
	input := antlr.NewInputStream(query)
	// converts tokens to upper case, so now it doesn't matter
	// in which case the tokens were entered
	upper := newCaseChangingStream(input, true)

	lexer := fql.NewFqlLexer(upper)
	stream := antlr.NewCommonTokenStream(lexer, antlr.TokenDefaultChannel)

	p := fql.NewFqlParser(stream)
	p.BuildParseTrees = true

	return &Parser{tree: p}
}