type_varsl
Type.type_varsl : hol_type list -> hol_type list
Returns the set of type variables in a list of types.
An invocation type_varsl [ty1,...,tyn] returns a list representing the
set-theoretic union of the type variables occurring in ty1,...,tyn.
Failure
Never fails.
Example
> type_varsl [alpha, beta, bool, ((alpha --> beta) --> bool --> beta)];
val it = [“:β”, “:α”]: hol_type list
Comments
Code should not depend on how elements are arranged in the result of
type_varsl.
See also
Type.type_vars,
Type.type_vars_acc,
Type.type_var_in,
Type.exists_tyvar,
Type.polymorphic,
Term.free_vars