function command() {
    return C.char('!').drop()
        .then(C.text())
        .then(C.char(':').drop())
        .then(C.char(' ').optrep().drop())

}

function textCommand() {

    return command()
        .then(C.text())
        .then(F.eol.drop())
        .map(vals => ({
            type: 'command',
            command: vals[0],
            text: vals[1]
        }));
}

function namedCommand(commandName:string, key=commandName) {

    return command()
        .then(C.string(commandName))
        .then(F.eol.drop())
        .map(values => {
            const result = {
                type: 'command',
                command: values[0]
            };
            result[key] = values[1];
            return result;
        });
}

function blank() {
    return C.charIn(' \t');
}

function title(){
    return C.char('=').rep().drop()
        .then(lettersOrBlanks()).then(eol().drop())
        .map(val => ({title:val.trim()}) );
}

function eol() {
    return C.string('\r\n').or(C.char('\n'));
}

function letterOrBlank(){
    return F.try(C.letter).or(C.char(' '));
}