gram is executed, the computation <span 
class="pcrr7t-">main</span> is
performed, and its result (of type <span 
class="cmmi-10">&tau;</span>) is discarded.
 <p class="noindent"> Modules may reference other modules via explicit <span 
class="pcrr7t-">import</span> declarations, each giving the name of a module to be
imported and specifying its entities to be imported. Modules may be mutually recursive.
 <p class="noindent"> Modules are used for name-space control, and are not first class values. A multi-mo