I have been going through the documentation, trying to figure out which 
constructs in Ocaml are syntactic (like :: seems to be) and cannot be 
oer-ridden, and others like + which are values in Pervasives.  Is there 
a simple way to find out which language constructs are purely syntactic?

The goal is to understand which constructs can be re-defined (locally) 
in a module.  The eventual application is a more genial syntax for a DSL 
implemented via MetaOCaml (and more functors than anyone in their right 
mind would really want to use...).

Jacques