Warren Teitelman implemented a rule-based command correction facility in BBN Lisp in the 1960s (https://dspace.mit.edu/handle/1721.1/6905 https://dspace.mit.edu

Warren Teitelman implemented a rule-based command correction facility in BBN Lisp in the 1960s (https://dspace.mit.edu/handle/1721.1/6905 https://dspace.mit.edu/handle/1721.1/6905) that later became known as DWIM in InterLisp (http://www.softwarepreservation.org/projects/LISP/interlisp-d/3100186-Interlisp_Oct83.pdf/view http://www.softwarepreservation.org/projects/LISP/interlisp-...). It was notorious for introducing weird errors: https://groups.google.com/d/msg/comp.lang.misc/hBQ1autWqlI/IL0TYoHljXEJ https://groups.google.com/d/msg/comp.lang.misc/hBQ1autWqlI/I.... There is also an anecdote about it deleting files in ESR's Hacker's Dictionary (http://www.catb.org/jargon/html/D/DWIM.html http://www.catb.org/jargon/html/D/DWIM.html) that seems to be ESR's made up bullshit - the syntax is wrong, the anecdote is not in the old jargon file, and also the fact that Interlisp had undelete. A lot of people seemed to have liked the facility though.