From 8f378db6612a6d38f39df935d841b656f6d7ad90 Mon Sep 17 00:00:00 2001
From: Leonardo de Moura <leonardo@microsoft.com>
Date: Thu, 12 Nov 2015 20:38:54 -0800
Subject: [PATCH] feat(library/blast): add normalize procedure to blast API

---
 src/frontends/lean/builtin_cmds.cpp |  4 ++--
 src/library/blast/blast.cpp         | 26 ++++++++++++++++++++++----
 src/library/blast/blast.h           |  5 +++++
 3 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/src/frontends/lean/builtin_cmds.cpp b/src/frontends/lean/builtin_cmds.cpp
index 189e1bddb..04f0ff496 100644
--- a/src/frontends/lean/builtin_cmds.cpp
+++ b/src/frontends/lean/builtin_cmds.cpp
@@ -1359,8 +1359,8 @@ static environment normalizer_cmd(parser & p) {
     environment const & env = p.env();
     expr e; level_param_names ls;
     std::tie(e, ls) = parse_local_expr(p);
-    tmp_type_context ctx(env, p.ios());
-    expr r = normalizer(ctx)(e);
+    blast::scope_debug scope(p.env(), p.ios());
+    expr r = blast::normalize(e);
     p.regular_stream() << r << endl;
     return env;
 }
diff --git a/src/library/blast/blast.cpp b/src/library/blast/blast.cpp
index 8b048c55d..1de67004b 100644
--- a/src/library/blast/blast.cpp
+++ b/src/library/blast/blast.cpp
@@ -354,19 +354,22 @@ class blastenv {
         g.get_hyps(hs);
         for (expr const & h : hs) {
             lean_assert(is_local(h));
-            expr type     = normalize(*norm_tc, mlocal_type(h));
+            // TODO(Leo): cleanup this stuff... we don't have to use this normalizer anymore...
+            expr type     = ::lean::normalize(*norm_tc, mlocal_type(h));
             expr new_type = to_blast_expr(type);
             expr href     = s.mk_hypothesis(local_pp_name(h), new_type, h);
             local2href.insert(mlocal_name(h), href);
         }
-        expr target     = normalize(*norm_tc, g.get_type());
+        expr target     = ::lean::normalize(*norm_tc, g.get_type());
         expr new_target = to_blast_expr(target);
         s.set_target(new_target);
         lean_assert(s.check_invariant());
         return s;
     }
 
-    tctx m_tctx;
+    tctx                       m_tctx;
+    normalizer                 m_normalizer;
+    expr_map<expr>             m_norm_cache; // normalization cache
 
     void save_initial_context() {
         hypothesis_idx_buffer hidxs;
@@ -403,7 +406,8 @@ public:
         m_app_builder(*m_tmp_ctx),
         m_fun_info_manager(*m_tmp_ctx),
         m_congr_lemma_manager(m_app_builder, m_fun_info_manager),
-        m_tctx(*this) {
+        m_tctx(*this),
+        m_normalizer(m_tctx) {
         init_uref_mref_href_idxs();
     }
 
@@ -493,6 +497,15 @@ public:
     type_context & get_type_context() {
         return m_tctx;
     }
+
+    expr normalize(expr const & e) {
+        auto it = m_norm_cache.find(e);
+        if (it != m_norm_cache.end())
+            return it->second;
+        expr r = m_normalizer(e);
+        m_norm_cache.insert(mk_pair(e, r));
+        return r;
+    }
 };
 
 LEAN_THREAD_PTR(blastenv, g_blastenv);
@@ -548,6 +561,11 @@ expr infer_type(expr const & e) {
     return g_blastenv->infer_type(e);
 }
 
+expr normalize(expr const & e) {
+    lean_assert(g_blastenv);
+    return g_blastenv->normalize(e);
+}
+
 bool is_prop(expr const & e) {
     lean_assert(g_blastenv);
     return g_blastenv->is_prop(e);
diff --git a/src/library/blast/blast.h b/src/library/blast/blast.h
index 27b3b337a..e7040e4e9 100644
--- a/src/library/blast/blast.h
+++ b/src/library/blast/blast.h
@@ -37,6 +37,11 @@ projection_info const * get_projection_info(name const & n);
 /** \brief Put the given expression in weak-head-normal-form with respect to the
     current state being processed by the blast tactic. */
 expr whnf(expr const & e);
+/** \brief Normalize the given expression using the blast type context.
+    This procedure caches results.
+    \remark This procedure is intended for normalizing instances that are not subsingletons. */
+expr normalize(expr const & e);
+
 /** \brief Return the type of the given expression with respect to the current state being
     processed by the blast tactic.