The Evolution of Language
Descartes:
2x
Church:
λx.2x
McCarthy:
(LAMBDA (X) (* 2 X))
W3C:
<?xml version="1.0"?>
<LAMBDATERM>
<VARLIST>
<VAR> X </VAR>
</VARLIST>
<EXPR>
<APPLICATION>
<EXPR> <CONST> * </CONST> </EXPR>
<ARGUMENTLIST>
<EXPR> <CONST> 2 </CONST> </EXPR>
<EXPR> <VAR> X </VAR> </EXPR>
</ARGUMENTLIST>
</APPLICATION>
</EXPR>
</LAMBDATERM>