Testing quote/backquote expressions. # To get expand. $(use "env3.ml") y is bound to "$y" u is bound to "$u" The Htmlc variable 'x' is not bound, hence if the quotation mechanism is broken, Htmlc will try to evaluate x and fail in the following line. Suppose the variable quoted defined as $('let quoted = $x');; x is now bound to "$x" and quoted to "$quoted". We test if $quoted is still \$x. $x ' x $x' \$('$x') And what about its expansion $(expand $quoted) which should be \$x. $(`'$x'`) which should be \$x. (`$quoted`) which should be \$x.