TITLE: The Evolution of Language AUTHOR: Eugene Wallingford DATE: December 08, 2004 2:14 PM DESC: An oldie but a goodie: from Descartes to XML ----- BODY: I've been reading about XML a bit lately, and I can't help but be reminded of a wonderful T-shirt I saw Philip Wadler wearing at the 2002 International Conference on Functional Programming. I know that this is an oldie, but it's still a goodie.

The Evolution of Language

                2x       (Descartes)

              λx.2x          (Church)

          (LAMBDA (X) (* 2 X))        (McCarthy)

     <?xml version="1.0"?>                (W3C)
     <LAMBDA-TERM>
       <VAR-LIST>
         <VAR> X </VAR>
       </VAR-LIST>
       <EXPR>
         <APPLICATION>
           <EXPR> <CONST> * </CONST> </EXPR>
           <ARGUMENT-LIST>
             <EXPR> <CONST> 2 </CONST> </EXPR>
             <EXPR> <VAR> X </VAR> </EXPR>
           </ARGUMENT-LIST>
         </APPLICATION>
       </EXPR>
     </LAMBDA-TERM>

Philip has a PDF version on line. -----