Editing MDL (programming language) (section)

==Code sample==
This is a sample of PDP-10 MDL:<ref>{{cite web |url=http://simh.trailing-edge.com/games/zork-mdl.zip |title=Zork-mdl.zip}}</ref><ref>{{cite web |url=http://simh.trailing-edge.com/software.html |title=Software Kits |last1=Supnik |first1=Bob |date=2018-06-04 |website=Computer Simulation and History (SimH) |publisher=Bitsavers.org |access-date=2018-12-18}}</ref><ref>{{cite web |url=http://pdp-11.ru/simh_trailing-edge_com/software.html |title=Software Kits |last1=Supnik |first1=Bob |date=2007-09-02 |website=Computer Simulation and History (SimH) |publisher=Forum PDP-11 |access-date=2018-12-18}}</ref>

<syntaxhighlight lang="clojure">
<DEFINE EXIT-TO (EXITS RMS)
        #DECL ((EXITS) EXIT (RMS) <UVECTOR [REST ROOM]>)
        <MAPF <>
              <FUNCTION (E)
                 #DECL ((E) <OR DIRECTION ROOM CEXIT NEXIT DOOR>)
                 <COND (<TYPE? .E DIRECTION>)
                       (<AND <TYPE? .E ROOM> <MEMQ .E .RMS>>
                        <MAPLEAVE T>)
                       (<AND <TYPE? .E CEXIT> <MEMQ <2 .E> .RMS>>
                        <MAPLEAVE T>)
                       (<AND <TYPE? .E DOOR>
                             <OR <MEMQ <DROOM1 .E> .RMS>
                                 <MEMQ <DROOM2 .E> .RMS>>>
                        <MAPLEAVE T>)>>
              .EXITS>>
</syntaxhighlight>