XML Document Type Definition

<!--              The Hacker's Diet Online
            http://www.fourmilab.ch/hackdiet/online/

             XML Database Document Type Definition

    This definition is cited with a:
        <!DOCTYPE hackersdiet SYSTEM
            "https://www.fourmilab.ch/hackdiet/online/hackersdiet.dtd">
    declaration in compliant XML files.

-->

    <!-- Root element -->

    <!ELEMENT hackersdiet
        (epoch?, account?, monthlogs?)
    >

    <!ATTLIST hackersdiet
        version     CDATA   #REQUIRED
    >

    <!ELEMENT epoch                 (#PCDATA)>

    <!ELEMENT account
        (user?, preferences?, diet-plan?)
    >

    <!ATTLIST account
        version     CDATA   #REQUIRED
    >

    <!ELEMENT monthlogs
        (monthlog*)
    >

    <!ATTLIST monthlogs
        version     CDATA   #REQUIRED
    >

    <!-- User information.  This element is optional but,
         if present, must be first in the file. -->

    <!ELEMENT user
        (login-name?,
         first-name?,
         middle-name?,
         last-name?,
         e-mail?,
         height?,
         account-created?)
    >

    <!ATTLIST user
        version     CDATA   #REQUIRED
    >

    <!ELEMENT login-name            (#PCDATA)>
    <!ELEMENT first-name            (#PCDATA)>
    <!ELEMENT middle-name           (#PCDATA)>
    <!ELEMENT last-name             (#PCDATA)>
    <!ELEMENT e-mail                (#PCDATA)>
    <!ELEMENT height                (#PCDATA)>
    <!ELEMENT account-created       (#PCDATA)>

    <!-- Preferences.  This element is optional but,
         if present, must be after the user information,
         if present.  -->

    <!ELEMENT preferences
        (log-unit?,
         display-unit?,
         energy-unit?,
         current-rung?,
         decimal-character?)
    >

    <!ATTLIST preferences
        version     CDATA   #REQUIRED
    >

    <!ELEMENT log-unit              (#PCDATA)>
    <!ELEMENT display-unit          (#PCDATA)>
    <!ELEMENT energy-unit           (#PCDATA)>
    <!ELEMENT current-rung          (#PCDATA)>
    <!ELEMENT decimal-character     (#PCDATA)>

    <!-- Diet plan.  This element is optional but,
         if present, must be after the preferences,
         if present.  -->

    <!ELEMENT diet-plan
        (calorie-balance?,
         start-weight?,
         goal-weight?,
         start-date?,
         show-plan?)
    >

    <!ATTLIST diet-plan
        version     CDATA   #REQUIRED
    >

    <!ELEMENT calorie-balance       (#PCDATA)>
    <!ELEMENT start-weight          (#PCDATA)>
    <!ELEMENT goal-weight           (#PCDATA)>
    <!ELEMENT start-date            (#PCDATA)>
    <!ELEMENT show-plan             (#PCDATA)>

    <!-- Monthly log.  Any number of monthly logs may
         appear, in any order. -->

    <!ELEMENT monthlog
        (properties, days)
    >

    <!ATTLIST monthlog
        version     CDATA   #REQUIRED
    >

    <!ELEMENT properties
        (year,
         month,
         weight-unit,
         trend-carry-forward?,
         last-modified?)
    >

    <!ELEMENT year                  (#PCDATA)>
    <!ELEMENT month                 (#PCDATA)>
    <!ELEMENT weight-unit           (#PCDATA)>
    <!ELEMENT trend-carry-forward   (#PCDATA)>
    <!ELEMENT last-modified         (#PCDATA)>

    <!ELEMENT days
        (day+)
    >

    <!ATTLIST days
        ndays       CDATA   #REQUIRED
    >

    <!ELEMENT day
        (date,
         weight,
         rung,
         flag,
         comment)
    >

    <!ELEMENT date                  (#PCDATA)>
    <!ELEMENT weight                (#PCDATA)>
    <!ELEMENT rung                  (#PCDATA)>
    <!ELEMENT flag                  (#PCDATA)>
    <!ELEMENT comment               (#PCDATA)>