mk_vartypeType.mk_vartype : string -> hol_type
Constructs a type variable of the given name.
Fails if the string does not begin with '.
> mk_vartype "'giraffe";
val it = “:'giraffe”: hol_type
> try mk_vartype "test";
val it = “:test”: hol_type
Type.dest_vartype,
Type.is_vartype, Type.mk_type