refactor(library/blast,frontends/lean): forward pattern index

src/frontends/lean/builtin_cmds.cpp

@@ -50,6 +50,7 @@ Author: Leonardo de Moura
 #include "library/blast/simplifier/simplifier.h"
 #include "library/blast/backward/backward_rule_set.h"
 #include "library/blast/forward/pattern.h"
+#include "library/blast/forward/forward_lemma_set.h"
 #include "compiler/preprocess_rec.h"
 #include "frontends/lean/util.h"
 #include "frontends/lean/parser.h"
@@ -231,20 +232,26 @@ static void print_metaclasses(parser const & p) {
         p.regular_stream() << "[" << n << "]" << endl;
 }
 
-static void print_patterns(io_state_stream const & out, environment const & env, name const & n) {
+static void print_patterns(parser const & p, name const & n) {
-    if (auto lemma = get_hi_lemma(env, n)) {
+    if (is_forward_lemma(p.env(), n)) {
-        if (lemma->m_multi_patterns) {
+        blast::scope_debug scope(p.env(), p.ios());
-            out << "(multi-)patterns:\n";
+        try {
-            for (multi_pattern const & mp : lemma->m_multi_patterns) {
+            // we regenerate the patterns to make sure they reflect the current set of reducible constants
-                out << "{";
+            auto lemma = blast::mk_hi_lemma(n, LEAN_FORWARD_LEMMA_DEFAULT_PRIORITY);
-                bool first = true;
+            if (lemma.m_multi_patterns) {
-                for (expr const & p : mp) {
+                io_state_stream out = p.regular_stream();
-                    if (first) first = false; else out << ", ";
+                out << "(multi-)patterns:\n";
-                    out << p;
+                for (multi_pattern const & mp : lemma.m_multi_patterns) {
+                    out << "{";
+                    bool first = true;
+                    for (expr const & p : mp) {
+                        if (first) first = false; else out << ", ";
+                        out << p;
+                    }
+                    out << "}\n";
                 }
-                out << "}\n";
             }
-        }
+        } catch (exception &) {}
     }
 }
 
@@ -287,7 +294,7 @@ static void print_attributes(parser const & p, name const & n) {
         out << " [backward]";
     if (is_no_pattern(env, n))
         out << " [no_pattern]";
-    if (get_hi_lemma(env, n))
+    if (is_forward_lemma(env, n))
         out << " [forward]";
     switch (get_reducible_status(env, n)) {
     case reducible_status::Reducible:      out << " [reducible]"; break;
@@ -424,7 +431,7 @@ bool print_id_info(parser const & p, name const & id, bool show_value, pos_info
                     if (show_value)
                         print_definition(p, c, pos);
                 }
-                print_patterns(out, env, c);
+                print_patterns(p, c);
             }
             return true;
         } catch (exception & ex) {}

src/frontends/lean/decl_attributes.cpp

@@ -14,6 +14,7 @@ Author: Leonardo de Moura
 #include "library/blast/simplifier/simp_rule_set.h"
 #include "library/blast/backward/backward_rule_set.h"
 #include "library/blast/forward/pattern.h"
+#include "library/blast/forward/forward_lemma_set.h"
 #include "frontends/lean/decl_attributes.h"
 #include "frontends/lean/parser.h"
 #include "frontends/lean/tokens.h"
@@ -241,9 +242,9 @@ environment decl_attributes::apply(environment env, io_state const & ios, name c
     }
     if (forward) {
         if (m_priority)
-            env = add_hi_lemma(env, ios.get_options(), d, *m_priority, m_persistent);
+            env = add_forward_lemma(env, d, *m_priority, m_persistent);
         else
-            env = add_hi_lemma(env, ios.get_options(), d, LEAN_HI_LEMMA_DEFAULT_PRIORITY, m_persistent);
+            env = add_forward_lemma(env, d, LEAN_FORWARD_LEMMA_DEFAULT_PRIORITY, m_persistent);
     }
     if (m_no_pattern) {
         env = add_no_pattern(env, d, m_persistent);

src/library/blast/forward/CMakeLists.txt

@@ -1,2 +1,2 @@
 add_library(forward OBJECT init_module.cpp forward_extension.cpp qcf.cpp pattern.cpp
-  ematch.cpp)
+  ematch.cpp forward_lemma_set.cpp)

src/library/blast/forward/ematch.cpp

@@ -13,6 +13,7 @@ Author: Leonardo de Moura
 #include "library/blast/options.h"
 #include "library/blast/congruence_closure.h"
 #include "library/blast/forward/pattern.h"
+#include "library/blast/forward/forward_lemma_set.h"
 
 namespace lean {
 namespace blast {
@@ -45,7 +46,6 @@ struct ematch_branch_extension : public branch_extension {
     hi_lemma_set                                  m_lemmas;
     hi_lemma_set                                  m_new_lemmas;
     rb_map<head_index, expr_set, head_index::cmp> m_apps;
-    name_set                                      m_initialized;
     expr_set                                      m_instances;
 
     ematch_branch_extension() {}
@@ -70,14 +70,6 @@ struct ematch_branch_extension : public branch_extension {
         case expr_kind::App: {
             buffer<expr> args;
             expr const & f = get_app_args(e, args);
-            if (is_constant(f) && !m_initialized.contains(const_name(f))) {
-                m_initialized.insert(const_name(f));
-                if (auto lemmas = get_hi_lemma_index(env()).find(const_name(f))) {
-                    for (hi_lemma const & lemma : *lemmas) {
-                        m_new_lemmas.insert(lemma);
-                    }
-                }
-            }
             if ((is_constant(f) && !is_no_pattern(env(), const_name(f))) ||
                 (is_local(f))) {
                 expr_set s;
@@ -95,16 +87,22 @@ struct ematch_branch_extension : public branch_extension {
 
     void register_lemma(hypothesis const & h) {
         if (is_pi(h.get_type()) && !is_arrow(h.get_type())) {
-            blast_tmp_type_context ctx;
             try {
-                m_new_lemmas.insert(mk_hi_lemma(*ctx, h.get_self()));
+                m_new_lemmas.insert(mk_hi_lemma(h.get_self()));
             } catch (exception &) {}
         }
     }
 
     virtual ~ematch_branch_extension() {}
     virtual branch_extension * clone() override { return new ematch_branch_extension(*this); }
-    virtual void initialized() override {}
+    virtual void initialized() override {
+        forward_lemma_set s = get_forward_lemma_set(env());
+        s.for_each([&](name const & n, unsigned prio) {
+                try {
+                    m_new_lemmas.insert(mk_hi_lemma(n, prio));
+                } catch (exception &) {}
+            });
+    }
     virtual void hypothesis_activated(hypothesis const & h, hypothesis_idx) override {
         collect_apps(h.get_type());
         register_lemma(h);

src/library/blast/forward/forward_lemma_set.cpp

@@ -0,0 +1,78 @@
+/*
+Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura
+*/
+#include "library/scoped_ext.h"
+#include "library/blast/forward/forward_lemma_set.h"
+
+namespace lean {
+static name * g_name       = nullptr;
+static std::string * g_key = nullptr;
+
+struct forward_lemma {
+    name      m_name;
+    unsigned  m_priority;
+    forward_lemma() {}
+    forward_lemma(name const & n, unsigned p):m_name(n), m_priority(p) {}
+};
+
+struct forward_lemma_set_config {
+    typedef forward_lemma     entry;
+    typedef forward_lemma_set state;
+
+    static void add_entry(environment const &, io_state const &, state & s, entry const & e) {
+        s.insert(e.m_name, e.m_priority);
+    }
+
+    static name const & get_class_name() {
+        return *g_name;
+    }
+
+    static std::string const & get_serialization_key() {
+        return *g_key;
+    }
+
+    static void  write_entry(serializer & s, entry const & e) {
+        s << e.m_name << e.m_priority;
+    }
+
+    static entry read_entry(deserializer & d) {
+        name n; unsigned p;
+        d >> n >> p;
+        return entry(n, p);
+    }
+
+    static optional<unsigned> get_fingerprint(entry const & e) {
+        return some(hash(e.m_name.hash(), e.m_priority));
+    }
+};
+
+template class scoped_ext<forward_lemma_set_config>;
+typedef scoped_ext<forward_lemma_set_config> forward_lemma_set_ext;
+
+environment add_forward_lemma(environment const & env, name const & n, unsigned priority, bool persistent) {
+    return forward_lemma_set_ext::add_entry(env, get_dummy_ios(), forward_lemma(n, priority), persistent);
+}
+
+bool is_forward_lemma(environment const & env, name const & n) {
+    return forward_lemma_set_ext::get_state(env).contains(n);
+}
+
+forward_lemma_set get_forward_lemma_set(environment const & env) {
+    return forward_lemma_set_ext::get_state(env);
+}
+
+void initialize_forward_lemma_set() {
+    g_name              = new name("forward");
+    g_key               = new std::string("FWD");
+    forward_lemma_set_ext::initialize();
+}
+
+void finalize_forward_lemma_set() {
+    forward_lemma_set_ext::finalize();
+    delete g_name;
+    delete g_key;
+}
+}

src/library/blast/forward/forward_lemma_set.h

@@ -0,0 +1,25 @@
+/*
+Copyright (c) 2015 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura
+*/
+#pragma once
+#include "util/rb_tree.h"
+#include "kernel/expr.h"
+
+#ifndef LEAN_FORWARD_LEMMA_DEFAULT_PRIORITY
+#define LEAN_FORWARD_LEMMA_DEFAULT_PRIORITY 1000
+#endif
+
+namespace lean {
+/** \brief The forward lemma set is actually a mapping from lemma name to priority */
+typedef rb_map<name, unsigned, name_quick_cmp> forward_lemma_set;
+
+environment add_forward_lemma(environment const & env, name const & n, unsigned priority, bool persistent);
+bool is_forward_lemma(environment const & env, name const & n);
+forward_lemma_set get_forward_lemma_set(environment const & env);
+
+void initialize_forward_lemma_set();
+void finalize_forward_lemma_set();
+}

src/library/blast/forward/init_module.cpp

@@ -5,6 +5,7 @@ Author: Daniel Selsam
 */
 #include "library/blast/forward/init_module.h"
 #include "library/blast/forward/forward_extension.h"
+#include "library/blast/forward/forward_lemma_set.h"
 #include "library/blast/forward/pattern.h"
 #include "library/blast/forward/ematch.h"
 
@@ -14,11 +15,13 @@ namespace blast {
 void initialize_forward_module() {
     initialize_forward_extension();
     initialize_pattern();
+    initialize_forward_lemma_set();
     initialize_ematch();
 }
 
 void finalize_forward_module() {
     finalize_ematch();
+    finalize_forward_lemma_set();
     finalize_pattern();
     finalize_forward_extension();
 }

src/library/blast/forward/pattern.cpp

@@ -6,7 +6,6 @@ Author: Leonardo de Moura
 */
 #include <string>
 #include "util/sstream.h"
-#include "util/sexpr/option_declarations.h"
 #include "library/expr_lt.h"
 #include "kernel/find_fn.h"
 #include "kernel/for_each_fn.h"
@@ -21,19 +20,11 @@ Author: Leonardo de Moura
 #include "library/scoped_ext.h"
 #include "library/idx_metavar.h"
 #include "library/blast/options.h"
+#include "library/blast/blast.h"
 #include "library/blast/forward/pattern.h"
-
+#include "library/blast/forward/forward_lemma_set.h"
-#ifndef LEAN_DEFAULT_PATTERN_MAX_STEPS
-#define LEAN_DEFAULT_PATTERN_MAX_STEPS 1024
-#endif
 
 namespace lean {
-static name * g_pattern_max_steps  = nullptr;
-
-unsigned get_pattern_max_steps(options const & o) {
-    return o.get_unsigned(*g_pattern_max_steps, LEAN_DEFAULT_PATTERN_MAX_STEPS);
-}
-
 /*
 Step 1: Selecting which variables we should track.
 
@@ -143,66 +134,19 @@ expr mk_pattern_hint(expr const & e) {
     return mk_annotation(*g_pattern_hint, e);
 }
 
-static name * g_hi_name    = nullptr;
+static name * g_name    = nullptr;
 static std::string * g_key = nullptr;
 
-// "Poor man" union type
+struct no_pattern_config {
-struct hi_entry {
+    typedef name     entry;
-    optional<name> m_no_pattern;
+    typedef name_set state;
-    hi_lemma       m_lemma;
-    hi_entry() {}
-    hi_entry(name const & n):m_no_pattern(n) {}
-    hi_entry(hi_lemma const & l):m_lemma(l) {}
-};
-
-struct hi_state {
-    name_set           m_no_patterns;
-    name_map<hi_lemma> m_name_to_lemma;
-    hi_lemmas          m_lemmas;
-};
-
-serializer & operator<<(serializer & s, multi_pattern const & mp) {
-    write_list(s, mp);
-    return s;
-}
-
-deserializer & operator>>(deserializer & d, multi_pattern & mp) {
-    mp = read_list<expr>(d);
-    return d;
-}
-
-static optional<name> get_hi_lemma_name(expr const & H) {
-    if (is_lambda(H))
-        return get_hi_lemma_name(binding_body(H));
-    expr const & f = get_app_fn(H);
-    if (is_constant(f))
-        return optional<name>(const_name(f));
-    else
-        return optional<name>();
-}
-
-struct hi_config {
-    typedef hi_entry entry;
-    typedef hi_state state;
 
     static void add_entry(environment const &, io_state const &, state & s, entry const & e) {
-        if (e.m_no_pattern) {
+        s.insert(e);
-            s.m_no_patterns.insert(*e.m_no_pattern);
-        } else {
-            if (auto n = get_hi_lemma_name(e.m_lemma.m_proof))
-                s.m_name_to_lemma.insert(*n, e.m_lemma);
-            for (multi_pattern const & mp : e.m_lemma.m_multi_patterns) {
-                for (expr const & p : mp) {
-                    lean_assert(is_app(p));
-                    lean_assert(is_constant(get_app_fn(p)));
-                    s.m_lemmas.insert(const_name(get_app_fn(p)), e.m_lemma);
-                }
-            }
-        }
     }
 
     static name const & get_class_name() {
-        return *g_hi_name;
+        return *g_name;
     }
 
     static std::string const & get_serialization_key() {
@@ -210,49 +154,36 @@ struct hi_config {
     }
 
     static void  write_entry(serializer & s, entry const & e) {
-        s << e.m_no_pattern;
+        s << e;
-        if (!e.m_no_pattern) {
-            hi_lemma const & l = e.m_lemma;
-            s << l.m_num_uvars << l.m_num_mvars << l.m_priority << l.m_prop << l.m_proof;
-            write_list(s, l.m_mvars);
-            write_list(s, l.m_is_inst_implicit);
-            write_list(s, l.m_multi_patterns);
-        }
     }
 
     static entry read_entry(deserializer & d) {
         entry e;
-        d >> e.m_no_pattern;
+        d >> e;
-        if (!e.m_no_pattern) {
-            hi_lemma & l = e.m_lemma;
-            d >> l.m_num_uvars >> l.m_num_mvars >> l.m_priority >> l.m_prop >> l.m_proof;
-            l.m_mvars            = read_list<expr>(d);
-            l.m_is_inst_implicit = read_list<bool>(d);
-            l.m_multi_patterns   = read_list<multi_pattern>(d);
-        }
         return e;
     }
 
     static optional<unsigned> get_fingerprint(entry const & e) {
-        return e.m_no_pattern ? some(e.m_no_pattern->hash()) : some(e.m_lemma.m_prop.hash());
+        return some(e.hash());
     }
 };
 
-template class scoped_ext<hi_config>;
+template class scoped_ext<no_pattern_config>;
-typedef scoped_ext<hi_config> hi_ext;
+typedef scoped_ext<no_pattern_config> no_pattern_ext;
 
 bool is_no_pattern(environment const & env, name const & n) {
-    return hi_ext::get_state(env).m_no_patterns.contains(n);
+    return no_pattern_ext::get_state(env).contains(n);
 }
 
 environment add_no_pattern(environment const & env, name const & n, bool persistent) {
-    return hi_ext::add_entry(env, get_dummy_ios(), hi_entry(n), persistent);
+    return no_pattern_ext::add_entry(env, get_dummy_ios(), n, persistent);
 }
 
 name_set const & get_no_patterns(environment const & env) {
-    return hi_ext::get_state(env).m_no_patterns;
+    return no_pattern_ext::get_state(env);
 }
 
+namespace blast {
 typedef rb_tree<unsigned, unsigned_cmp> idx_metavar_set;
 
 static bool is_higher_order(tmp_type_context & ctx, expr const & e) {
@@ -363,7 +294,7 @@ struct mk_hi_lemma_fn {
 
     mk_hi_lemma_fn(tmp_type_context & ctx, expr const & H,
                    unsigned num_uvars, unsigned prio, unsigned max_steps):
-        m_ctx(ctx), m_no_patterns(hi_ext::get_state(ctx.env()).m_no_patterns),
+        m_ctx(ctx), m_no_patterns(no_pattern_ext::get_state(ctx.env())),
         m_H(H), m_num_uvars(num_uvars), m_priority(prio), m_max_steps(max_steps) {}
 
     struct candidate {
@@ -599,7 +530,12 @@ struct mk_hi_lemma_fn {
     }
 
     hi_lemma operator()() {
-        expr H_type = m_ctx.infer(m_H);
+        expr H_type;
+        {
+            // preserve pattern hints
+            scope_unfold_macro_pred scope1([](expr const & e) { return !is_pattern_hint(e); });
+            H_type = normalize(m_ctx.infer(m_H));
+        }
         buffer<bool> inst_implicit_flags;
         expr B      = extract_trackable(m_ctx, H_type, m_mvars, inst_implicit_flags, m_trackable, m_residue);
         lean_assert(m_mvars.size() == inst_implicit_flags.size());
@@ -652,52 +588,37 @@ hi_lemma mk_hi_lemma_core(tmp_type_context & ctx, expr const & H, unsigned num_u
     return mk_hi_lemma_fn(ctx, H, num_uvars, priority, max_steps)();
 }
 
-namespace blast {
+hi_lemma mk_hi_lemma(expr const & H) {
-hi_lemma mk_hi_lemma(tmp_type_context & ctx, expr const & H) {
+    blast_tmp_type_context ctx;
     unsigned max_steps = get_config().m_pattern_max_steps;
-    ctx.clear();
+    return mk_hi_lemma_core(*ctx, H, 0, LEAN_FORWARD_LEMMA_DEFAULT_PRIORITY, max_steps);
-    return mk_hi_lemma_core(ctx, H, 0, LEAN_HI_LEMMA_DEFAULT_PRIORITY, max_steps);
+}
-}}
 
-environment add_hi_lemma(environment const & env, options const & o, name const & c, unsigned priority, bool persistent) {
+hi_lemma mk_hi_lemma(name const & c, unsigned priority) {
-    tmp_type_context ctx(env, get_dummy_ios());
+    blast_tmp_type_context ctx;
-    declaration const & d = env.get(c);
+    unsigned max_steps = get_config().m_pattern_max_steps;
+    declaration const & d = env().get(c);
     buffer<level> us;
     unsigned num_us = d.get_num_univ_params();
     for (unsigned i = 0; i < num_us; i++)
-        us.push_back(ctx.mk_uvar());
+        us.push_back(ctx->mk_uvar());
-    expr H             = mk_constant(c, to_list(us));
+    expr H          = mk_constant(c, to_list(us));
-    unsigned max_steps = get_pattern_max_steps(o);
+    return mk_hi_lemma_core(*ctx, H, num_us, priority, max_steps);
-    return hi_ext::add_entry(env, get_dummy_ios(), hi_entry(mk_hi_lemma_core(ctx, H, num_us, priority, max_steps)),
-                             persistent);
 }
-
-hi_lemma const * get_hi_lemma(environment const & env, name const & c) {
-    return hi_ext::get_state(env).m_name_to_lemma.find(c);
-}
-
-hi_lemmas get_hi_lemma_index(environment const & env) {
-    return hi_ext::get_state(env).m_lemmas;
 }
 
 void initialize_pattern() {
-    g_hi_name           = new name("hi");
+    g_name              = new name("no_pattern");
-    g_key               = new std::string("HI");
+    g_key               = new std::string("NOPAT");
-    hi_ext::initialize();
+    no_pattern_ext::initialize();
     g_pattern_hint      = new name("pattern_hint");
     register_annotation(*g_pattern_hint);
-    g_pattern_max_steps = new name{"pattern", "max_steps"};
-    register_unsigned_option(*g_pattern_max_steps, LEAN_DEFAULT_PATTERN_MAX_STEPS,
-                             "(pattern) max number of steps performed by pattern inference procedure, "
-                             "we have this threshold because in the worst case this procedure may take "
-                             "an exponetial number of steps");
 }
 
 void finalize_pattern() {
-    hi_ext::finalize();
+    no_pattern_ext::finalize();
-    delete g_hi_name;
+    delete g_name;
     delete g_key;
     delete g_pattern_hint;
-    delete g_pattern_max_steps;
 }
 }

src/library/blast/forward/pattern.h

@@ -10,10 +10,6 @@ Author: Leonardo de Moura
 #include "library/expr_lt.h"
 #include "library/tmp_type_context.h"
 
-#ifndef LEAN_HI_LEMMA_DEFAULT_PRIORITY
-#define LEAN_HI_LEMMA_DEFAULT_PRIORITY 1000
-#endif
-
 namespace lean {
 /** \brief Annotate \c e as a pattern hint */
 expr mk_pattern_hint(expr const & e);
@@ -52,27 +48,11 @@ struct hi_lemma_cmp {
     int operator()(hi_lemma const & l1, hi_lemma const & l2) const { return expr_quick_cmp()(l1.m_prop, l2.m_prop); }
 };
 
-/** \brief Mapping c -> S, where c is a constant name and S is a set of hi_lemmas that contain
-    a pattern where the head symbol is c. */
-typedef rb_multi_map<name, hi_lemma, name_quick_cmp> hi_lemmas;
-
-/** \brief Add the given theorem as a heuristic instantiation lemma in the current environment. */
-environment add_hi_lemma(environment const & env, options const & o, name const & c, unsigned priority, bool persistent);
-
-/** \brief Return the heuristic instantiation lemma data associated with constant \c c */
-hi_lemma const * get_hi_lemma(environment const & env, name const & c);
-
-/** \brief Retrieve the active set of heuristic instantiation lemmas. */
-hi_lemmas get_hi_lemma_index(environment const & env);
-
-hi_lemma mk_hi_lemma(tmp_type_context & ctx, expr const & H, unsigned max_steps);
-
-unsigned get_pattern_max_steps(options const & o);
-
 namespace blast {
 /** \brief Create a (local) heuristic instantiation lemma for \c H.
     The maximum number of steps is extracted from the blast config object. */
-hi_lemma mk_hi_lemma(tmp_type_context & ctx, expr const & H);
+hi_lemma mk_hi_lemma(expr const & H);
+hi_lemma mk_hi_lemma(name const & n, unsigned prio);
 }
 
 void initialize_pattern();

src/library/blast/options.cpp

@@ -44,7 +44,9 @@ Author: Leonardo de Moura
 #ifndef LEAN_DEFAULT_BLAST_BACKWARD
 #define LEAN_DEFAULT_BLAST_BACKWARD true
 #endif
-
+#ifndef LEAN_DEFAULT_PATTERN_MAX_STEPS
+#define LEAN_DEFAULT_PATTERN_MAX_STEPS 1024
+#endif
 
 namespace lean {
 namespace blast {
@@ -61,6 +63,7 @@ static name * g_blast_recursor     = nullptr;
 static name * g_blast_ematch       = nullptr;
 static name * g_blast_backward     = nullptr;
 static name * g_blast_show_failure = nullptr;
+static name * g_pattern_max_steps  = nullptr;
 
 unsigned get_blast_max_depth(options const & o) {
     return o.get_unsigned(*g_blast_max_depth, LEAN_DEFAULT_BLAST_MAX_DEPTH);
@@ -98,6 +101,9 @@ bool get_blast_backward(options const & o) {
 bool get_blast_show_failure(options const & o) {
     return o.get_bool(*g_blast_show_failure, LEAN_DEFAULT_BLAST_SHOW_FAILURE);
 }
+unsigned get_pattern_max_steps(options const & o) {
+    return o.get_unsigned(*g_pattern_max_steps, LEAN_DEFAULT_PATTERN_MAX_STEPS);
+}
 
 config::config(options const & o) {
     m_max_depth         = get_blast_max_depth(o);
@@ -145,6 +151,7 @@ void initialize_options() {
     g_blast_ematch       = new name{"blast", "ematch"};
     g_blast_backward     = new name{"blast", "backward"};
     g_blast_show_failure = new name{"blast", "show_failure"};
+    g_pattern_max_steps  = new name{"pattern", "max_steps"};
 
     register_unsigned_option(*blast::g_blast_max_depth, LEAN_DEFAULT_BLAST_MAX_DEPTH,
                              "(blast) max search depth for blast");
@@ -170,6 +177,10 @@ void initialize_options() {
                          "(blast) enable backward chaining");
     register_bool_option(*blast::g_blast_show_failure, LEAN_DEFAULT_BLAST_SHOW_FAILURE,
                          "(blast) show failure state");
+    register_unsigned_option(*g_pattern_max_steps, LEAN_DEFAULT_PATTERN_MAX_STEPS,
+                             "(pattern) max number of steps performed by pattern inference procedure, "
+                             "we have this threshold because in the worst case this procedure may take "
+                             "an exponetial number of steps");
 }
 void finalize_options() {
     delete g_blast_max_depth;
@@ -184,5 +195,6 @@ void finalize_options() {
     delete g_blast_ematch;
     delete g_blast_backward;
     delete g_blast_show_failure;
+    delete g_pattern_max_steps;
 }
 }}

tests/lean/pattern_hint1.lean

@@ -0,0 +1,9 @@
+constants f g : nat → Prop
+
+definition foo₁ [forward] : ∀ x, f x ∧ g x            := sorry
+definition foo₂ [forward] : ∀ x, (: f x :) ∧ g x      := sorry
+definition foo₃ [forward] : ∀ x, (: f (id x) :) ∧ g x := sorry
+
+print foo₁
+print foo₂
+print foo₃ -- id is unfolded

tests/lean/pattern_hint1.lean.expected.out

@@ -0,0 +1,13 @@
+definition foo₁ [forward] : ∀ (x : ℕ), f x ∧ g x :=
+sorry
+(multi-)patterns:
+{f ?M_1}
+{g ?M_1}
+definition foo₂ [forward] : ∀ (x : ℕ), (:f x:) ∧ g x :=
+sorry
+(multi-)patterns:
+{f ?M_1}
+definition foo₃ [forward] : ∀ (x : ℕ), (:f (id x):) ∧ g x :=
+sorry
+(multi-)patterns:
+{f ?M_1}

tests/lean/redundant_pattern.lean.expected.out

@@ -0,0 +1,4 @@
+definition foo [forward] : ∀ (m n k : ℕ), P (f m) → P (g n) → P (f k) → P k ∧ R (g m) (f n) ∧ P (g m) ∧ P (f n) :=
+λ (m n k : ℕ), sorry
+(multi-)patterns:
+{P ?M_1, R (g ?M_2) (f ?M_3)}