feat(kernel): add function param_names_to_levels

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

src/kernel/inductive/inductive.cpp

@@ -187,7 +187,7 @@ struct add_inductive_fn {
         m_env(env), m_level_names(level_params), m_num_params(num_params), m_decls(decls),
         m_ngen(g_tmp_prefix), m_tc(m_env) {
         m_decls_sz = length(m_decls);
-        m_levels = map2<level>(level_params, [](name const & n) { return mk_param_univ(n); });
+        m_levels = param_names_to_levels(level_params);
     }
 
     /** \brief Return the number of inductive datatypes being defined. */

src/kernel/level.cpp

@@ -686,5 +686,8 @@ bool is_geq_core(level l1, level l2) {
 bool is_geq(level const & l1, level const & l2) {
     return is_geq_core(normalize(l1), normalize(l2));
 }
+levels param_names_to_levels(level_param_names const & ps) {
+    return map2<level>(ps, [](name const & p) { return mk_param_univ(p); });
+}
 }
 void print(lean::level const & l) { std::cout << l << std::endl; }

src/kernel/level.h

@@ -218,5 +218,7 @@ format pp(level const & l, options const & opts = options());
 format pp(level const & lhs, level const & rhs, bool unicode, unsigned indent);
 /** \brief Pretty print lhs <= rhs using the given configuration options. */
 format pp(level const & lhs, level const & rhs, options const & opts = options());
+/** \brief Convert a list of universe level parameter names into a list of levels. */
+levels param_names_to_levels(level_param_names const & ps);
 }
 void print(lean::level const & l);

src/library/scope.cpp

@@ -39,7 +39,7 @@ struct decl_info {
     decl_info(unsigned pos, level_param_names const & lvl_deps, dependencies const & var_deps, expr const & type,
               binder_info const & bi, bool local):
         m_pos(pos), m_level_deps(lvl_deps), m_var_deps(var_deps), m_type(type), m_binder_info(bi), m_local(local) {
-        m_levels = map2<level>(m_level_deps, [](name const & n) { return mk_param_univ(n); });
+        m_levels = param_names_to_levels(m_level_deps);
     }
 };
 
@@ -342,7 +342,7 @@ environment add_inductive(environment                  env,
                 }
                 // collect new params and level_params
                 level_param_names extra_ls = ctx.mk_level_deps();
-                levels extra_lvls          = map2<level>(extra_ls, [](name const & n) { return mk_param_univ(n); });
+                levels extra_lvls          = param_names_to_levels(extra_ls);
                 dependencies extra_ps      = ctx.mk_var_deps();
                 unsigned new_num_params    = num_params + extra_ps.size();
                 level_param_names new_ls   = append(extra_ls, s_level_params);