If your set of symbol is closed, you can use a variant type (sum type).<div><br></div><div>type symbols =</div><div>| A</div><div>| B</div><div><br></div><div><br></div><div>If you really need open symbols, you can use [polymorphic variants].</div>

<div><br></div><div>Let tag_a foo = (`A, foo)</div><div><br></div><div> [polymorphic variants] <a href="http://caml.inria.fr/pub/docs/manual-ocaml/manual006.html#toc36">http://caml.inria.fr/pub/docs/manual-ocaml/manual006.html#toc36</a></div>

<div><br></div><div><br></div><div>However, you won&#39;t have convenience functions such as string_of_symbol; you would have to define them yourself.</div><meta http-equiv="content-type" content="text/html; charset=utf-8">