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: interface.go
    path of file: ./repos/lgo/parser
    
    the code of the file until where you have to start completion: // Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This file contains the exported entry points for invoking the parser.

package parser

import (
	"bytes"
	"errors"
	"go/ast"
	"go/token"
	"io"
	
    
func ParseFile(fset *token.FileSet, filename string, src interface{}, mode Mode) (f *ast.File, err error) {
	if fset == nil {
		panic("parser.ParseFile: no token.FileSet provided (fset == nil)")
	}

	// get source
	text, err := readSource(filename, src)
	if err != nil {
		return nil, err
	}

	var p parser
	defer func() {
		if e := recover(); e != nil {
			// resume same panic if it's not a bailout
			if _, ok := e.(bailout); !ok {
				panic(e)
			}
		}

		// set result values
		if f == nil {
			// source is not a valid Go source file - satisfy
			// ParseFile API and return a valid (but) empty
			// *ast.File
			f = &ast.File{
				Name:  new(ast.Ident),
				Scope: ast.NewScope(nil),
			}
		}

		p.errors.Sort()
		err = p.errors.Err()
	}()

	// parse source
	p.init(fset, filename, text, mode)
	f = p.parseFile()

	return
}