feat(library/tactic): add hole_command bookkeeping

library/init/meta/hole_command.lean

@@ -0,0 +1,48 @@
+/-
+Copyright (c) 2017 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+Authors: Leonardo de Moura
+-/
+prelude
+import init.meta.tactic
+
+/--
+The front-end (e.g., Emacs, VS Code) can invoke commands for holes {! ... !} in
+a declaration. A command is a tactic that takes the optional pre-term in the
+hole, and returns a list of expressions. The Lean server converts the list
+into a list of strings using the pretty printer, and return it to the front-end.
+Each string represents a different way to fill the hole.
+The front-end is responsible for replacing the hole with the user selected alternative.
+
+This infra-structure can be use to implement auto-fill and/or refine commands.
+
+An action may return an empty list. This is useful for actions that just return
+information such as the type of an expression, its normal form, etc.
+-/
+meta structure hole_command :=
+(name   : string)
+(descr  : string)
+(action : option pexpr → tactic (list expr))
+
+open tactic
+
+@[hole_command]
+meta def infer_type_cmd : hole_command :=
+{ name   := "Infer",
+  descr  := "Infer type of the expression in the hole",
+  action := λ o, do
+    some p ← return o | fail "Infer command, hole does not contain a term",
+    e ← to_expr p,
+    t ← infer_type e,
+    trace t,
+    return []
+}
+
+@[hole_command]
+meta def show_goal_cmd : hole_command :=
+{ name   := "Show",
+  descr  := "Show the current goal",
+  action := λ _, do
+    trace_state,
+    return []
+}

src/library/constants.cpp

@@ -119,6 +119,7 @@ name const * g_heq_refl = nullptr;
 name const * g_heq_symm = nullptr;
 name const * g_heq_trans = nullptr;
 name const * g_heq_of_eq = nullptr;
+name const * g_hole_command = nullptr;
 name const * g_id_locked = nullptr;
 name const * g_if_neg = nullptr;
 name const * g_if_pos = nullptr;
@@ -491,6 +492,7 @@ void initialize_constants() {
     g_heq_symm = new name{"heq", "symm"};
     g_heq_trans = new name{"heq", "trans"};
     g_heq_of_eq = new name{"heq_of_eq"};
+    g_hole_command = new name{"hole_command"};
     g_id_locked = new name{"id_locked"};
     g_if_neg = new name{"if_neg"};
     g_if_pos = new name{"if_pos"};
@@ -864,6 +866,7 @@ void finalize_constants() {
     delete g_heq_symm;
     delete g_heq_trans;
     delete g_heq_of_eq;
+    delete g_hole_command;
     delete g_id_locked;
     delete g_if_neg;
     delete g_if_pos;
@@ -1236,6 +1239,7 @@ name const & get_heq_refl_name() { return *g_heq_refl; }
 name const & get_heq_symm_name() { return *g_heq_symm; }
 name const & get_heq_trans_name() { return *g_heq_trans; }
 name const & get_heq_of_eq_name() { return *g_heq_of_eq; }
+name const & get_hole_command_name() { return *g_hole_command; }
 name const & get_id_locked_name() { return *g_id_locked; }
 name const & get_if_neg_name() { return *g_if_neg; }
 name const & get_if_pos_name() { return *g_if_pos; }

src/library/constants.h

@@ -121,6 +121,7 @@ name const & get_heq_refl_name();
 name const & get_heq_symm_name();
 name const & get_heq_trans_name();
 name const & get_heq_of_eq_name();
+name const & get_hole_command_name();
 name const & get_id_locked_name();
 name const & get_if_neg_name();
 name const & get_if_pos_name();

src/library/constants.txt

@@ -114,6 +114,7 @@ heq.refl
 heq.symm
 heq.trans
 heq_of_eq
+hole_command
 id_locked
 if_neg
 if_pos

src/library/tactic/CMakeLists.txt

@@ -8,5 +8,5 @@ add_library(tactic OBJECT occurrences.cpp kabstract.cpp tactic_state.cpp
   hsubstitution.cpp gexpr.cpp elaborate.cpp init_module.cpp
   simp_result.cpp user_attribute.cpp eval.cpp
   simp_lemmas.cpp eqn_lemmas.cpp dsimplify.cpp simplify.cpp
-  vm_monitor.cpp destruct_tactic.cpp norm_num_tactic.cpp
+  vm_monitor.cpp destruct_tactic.cpp norm_num_tactic.cpp hole_command.cpp
   elaborator_exception.cpp algebraic_normalizer.cpp tactic_evaluator.cpp)

src/library/tactic/hole_command.cpp

@@ -0,0 +1,87 @@
+/*
+Copyright (c) 2017 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura
+*/
+#include <string>
+#include <limits>
+#include "util/name_hash_map.h"
+#include "library/constants.h"
+#include "library/util.h"
+#include "library/attribute_manager.h"
+#include "library/scoped_ext.h"
+#include "library/vm/vm_string.h"
+#include "library/tactic/tactic_state.h"
+
+namespace lean {
+/* Persisting */
+struct hole_command_ext : public environment_extension {
+    name_map<pair<name, std::string>> m_cmds;
+};
+
+struct hole_command_ext_reg {
+    unsigned m_ext_id;
+    hole_command_ext_reg() { m_ext_id = environment::register_extension(std::make_shared<hole_command_ext>()); }
+};
+
+static hole_command_ext_reg * g_ext = nullptr;
+static hole_command_ext const & get_extension(environment const & env) {
+    return static_cast<hole_command_ext const &>(env.get_extension(g_ext->m_ext_id));
+}
+static environment update(environment const & env, hole_command_ext const & ext) {
+    return env.update(g_ext->m_ext_id, std::make_shared<hole_command_ext>(ext));
+}
+
+static environment add_hole_command(environment const & env, name const & d) {
+    auto const & ty = env.get(d).get_type();
+    if (!is_constant(ty, get_hole_command_name()))
+        throw exception("invalid [hole_command], must be applied to definition of type hole_command");
+
+    vm_state vm(env, options());
+    vm_obj o = vm.invoke(d, {});
+    name n(to_string(cfield(o, 0)));
+    hole_command_ext ext = get_extension(env);
+    if (ext.m_cmds.contains(n))
+        throw exception(sstream() << "hole commad named [" << n << "] has already been registered");
+    std::string descr = to_string(cfield(o, 1));
+    ext.m_cmds.insert(n, {n, descr});
+    return update(env, ext);
+}
+
+struct hole_command_modification : public modification {
+    LEAN_MODIFICATION("HOLE_CMD")
+    name m_name;
+
+    hole_command_modification() {}
+    hole_command_modification(name const & name) : m_name(name) {}
+
+    void perform(environment & env) const override {
+        env = add_hole_command(env, m_name);
+    }
+
+    void serialize(serializer & s) const override {
+        s << m_name;
+    }
+
+    static std::shared_ptr<modification const> deserialize(deserializer & d) {
+        return std::make_shared<hole_command_modification>(read_name(d));
+    }
+};
+
+void initialize_hole_command() {
+    register_system_attribute(basic_attribute(
+            "hole_command", "register a definition of type `hole_command` in the system",
+            [](environment const & env, io_state const &, name const & n, unsigned, bool persistent) {
+                if (!persistent)
+                    throw exception("illegal [hole_command] application, cannot be used locally");
+                return module::add_and_perform(env, std::make_shared<hole_command_modification>(n));
+            }));
+    g_ext = new hole_command_ext_reg();
+    hole_command_modification::init();
+}
+void finalize_hole_command() {
+    hole_command_modification::finalize();
+    delete g_ext;
+}
+}

src/library/tactic/hole_command.h

@@ -0,0 +1,11 @@
+/*
+Copyright (c) 2017 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura
+*/
+#pragma once
+namespace lean {
+void initialize_hole_command();
+void finalize_hole_command();
+}

src/library/tactic/init_module.cpp

@@ -35,6 +35,7 @@ Author: Leonardo de Moura
 #include "library/tactic/norm_num_tactic.h"
 #include "library/tactic/destruct_tactic.h"
 #include "library/tactic/algebraic_normalizer.h"
+#include "library/tactic/hole_command.h"
 #include "library/tactic/backward/init_module.h"
 #include "library/tactic/smt/init_module.h"
 
@@ -72,10 +73,12 @@ void initialize_tactic_module() {
     initialize_vm_monitor();
     initialize_destruct_tactic();
     initialize_algebraic_normalizer();
+    initialize_hole_command();
     initialize_smt_module();
 }
 void finalize_tactic_module() {
     finalize_smt_module();
+    finalize_hole_command();
     finalize_algebraic_normalizer();
     finalize_destruct_tactic();
     finalize_vm_monitor();

tests/lean/run/check_constants.lean

@@ -119,6 +119,7 @@ run_cmd script_check_id `heq.refl
 run_cmd script_check_id `heq.symm
 run_cmd script_check_id `heq.trans
 run_cmd script_check_id `heq_of_eq
+run_cmd script_check_id `hole_command
 run_cmd script_check_id `id_locked
 run_cmd script_check_id `if_neg
 run_cmd script_check_id `if_pos