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feat(kernel/inductive): add API for retrieving the number of indices in an inductive datatype

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This commit is contained in:
Leonardo de Moura 2014-10-25 10:42:05 -07:00
parent c30c0fa3b8
commit 9e69a95b26
2 changed files with 20 additions and 1 deletions
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16
src/kernel/inductive/inductive.cpp
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@ -182,6 +182,11 @@ static environment update(environment const & env, inductive_env_ext const & ext
return env.update(g_ext->m_ext_id, std::make_shared<inductive_env_ext>(ext));
}
/**\ brief Return recursor name */
static name get_elim_name(name const & n) {
return n + name("rec");
}
/** \brief Helper functional object for processing inductive datatype declarations. */
struct add_inductive_fn {
typedef std::unique_ptr<type_checker> type_checker_ptr;
@ -630,7 +635,7 @@ struct add_inductive_fn {
}
/** \brief Return the name of the eliminator/recursor for \c d. */
name get_elim_name(inductive_decl const & d) { return inductive_decl_name(d) + name("rec"); }
name get_elim_name(inductive_decl const & d) { return ::lean::inductive::get_elim_name(inductive_decl_name(d)); }
name get_elim_name(unsigned d_idx) { return get_elim_name(get_ith(m_decls, d_idx)); }
@ -957,6 +962,15 @@ optional<inductive_decls> is_inductive_decl(environment const & env, name const
return optional<inductive_decls>();
}
optional<unsigned> get_num_indices(environment const & env, name const & n) {
inductive_env_ext const & ext = get_extension(env);
if (auto it = ext.m_elim_info.find(get_elim_name(n))) {
return optional<unsigned>(it->m_num_indices);
} else {
return optional<unsigned>();
}
}
optional<name> is_intro_rule(environment const & env, name const & n) {
inductive_env_ext const & ext = get_extension(env);
if (auto it = ext.m_intro_info.find(n))

5
src/kernel/inductive/inductive.h
View file

@ -67,6 +67,11 @@ optional<name> is_elim_rule(environment const & env, name const & n);
/** \brief Given the eliminator \c n, this function return the position of major premise */
optional<unsigned> get_elim_major_idx(environment const & env, name const & n);
bool is_elim_meta_app(type_checker & tc, expr const & e);
/** \brief Return the number of indices in the given inductive datatype.
If \c n is not an inductive datatype in \c env, then return none.
*/
optional<unsigned> get_num_indices(environment const & env, name const & n);
}
void initialize_inductive_module();
void finalize_inductive_module();