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/go-doudou/toolkit/dbvendor/mysql/parser/parser
    
    the code of the file until where you have to start completion: /*
 * MIT License
 *
 * Copyright (c) 2021 zeromicro
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, m
    
func (p *Parser) From(filename string) (ret []*Table, err error) {
	if !filepath.IsAbs(filename) {
		return nil, fmt.Errorf("%s is not a valid path", filename)
	}

	defer func() {
		p := recover()
		if p != nil {
			switch e := p.(type) {
			case error:
				err = e
			default:
				err = fmt.Errorf("%+v", p)
			}
		}
	}()

	bytes, err := ioutil.ReadFile(filename)
	if err != nil {
		return nil, err
	}

	prefix := filepath.Base(filename)
	p.prefix = prefix
	inputStream := antlr.NewInputStream(string(bytes))
	caseChangingStream := newCaseChangingStream(inputStream, true)
	lexer := gen.NewMySqlLexer(caseChangingStream)
	lexer.RemoveErrorListeners()
	tokens := antlr.NewCommonTokenStream(lexer, antlr.LexerDefaultTokenChannel)
	mysqlParser := gen.NewMySqlParser(tokens)
	mysqlParser.RemoveErrorListeners()
	mysqlParser.AddErrorListener(p)

	visitor := &visitor{
		prefix: prefix,
		debug:  p.debug,
		logger: p.logger,
	}
	v := mysqlParser.Root().Accept(visitor)
	if v == nil {
		return empty, nil
	}

	createTables, ok := v.([]*CreateTable)
	if !ok {
		return empty, nil
	}

	for _, e := range createTables {
		ret = append(ret, e.Convert())
	}

	return
}