diff --git a/src/frontends/lean/CMakeLists.txt b/src/frontends/lean/CMakeLists.txt
index ce4982f05..d4787436d 100644
--- a/src/frontends/lean/CMakeLists.txt
+++ b/src/frontends/lean/CMakeLists.txt
@@ -1,6 +1,7 @@
 add_library(lean_frontend register_module.cpp token_table.cpp
 scanner.cpp parse_table.cpp parser_config.cpp parser.cpp
 parser_pos_provider.cpp builtin_cmds.cpp builtin_tactic_cmds.cpp
-builtin_exprs.cpp interactive.cpp notation_cmd.cpp calc.cpp)
+builtin_exprs.cpp interactive.cpp notation_cmd.cpp calc.cpp
+decl_cmds.cpp util.cpp)
 
 target_link_libraries(lean_frontend ${LEAN_LIBS})
diff --git a/src/frontends/lean/builtin_cmds.cpp b/src/frontends/lean/builtin_cmds.cpp
index c389c1429..2319e532c 100644
--- a/src/frontends/lean/builtin_cmds.cpp
+++ b/src/frontends/lean/builtin_cmds.cpp
@@ -11,20 +11,15 @@ Author: Leonardo de Moura
 #include "library/io_state_stream.h"
 #include "library/scoped_ext.h"
 #include "library/aliases.h"
-#include "library/private.h"
 #include "library/locals.h"
+#include "frontends/lean/util.h"
 #include "frontends/lean/parser.h"
 #include "frontends/lean/calc.h"
 #include "frontends/lean/notation_cmd.h"
+#include "frontends/lean/decl_cmds.h"
 
 namespace lean {
 static name g_raw("raw");
-static name g_llevel_curly(".{");
-static name g_rcurly("}");
-static name g_colon(":");
-static name g_assign(":=");
-static name g_private("[private]");
-static name g_inline("[inline]");
 static name g_true("true");
 static name g_false("false");
 static name g_options("options");
@@ -38,285 +33,6 @@ static name g_decls("decls");
 static name g_hiding("hiding");
 static name g_renaming("renaming");
 
-static void check_atomic(name const & n) {
-    if (!n.is_atomic())
-        throw exception(sstream() << "invalid declaration name '" << n << "', identifier must be atomic");
-}
-
-environment universe_cmd(parser & p) {
-    name n = p.check_id_next("invalid universe declaration, identifier expected");
-    check_atomic(n);
-    environment env = p.env();
-    if (in_section(env)) {
-        p.add_local_level(n, mk_param_univ(n));
-    } else {
-        name const & ns = get_namespace(env);
-        name full_n  = ns + n;
-        env = module::add_universe(env, full_n);
-        if (!ns.is_anonymous())
-            env = add_alias(env, n, mk_global_univ(full_n));
-    }
-    return env;
-}
-
-static void check_in_section(parser const & p) {
-    if (!in_section(p.env()))
-        throw exception(sstream() << "invalid command, it must be used in a section");
-}
-
-static void parse_univ_params(parser & p, buffer<name> & ps) {
-    if (p.curr_is_token(g_llevel_curly)) {
-        p.next();
-        while (!p.curr_is_token(g_rcurly)) {
-            name l = p.check_id_next("invalid universe parameter, identifier expected");
-            p.add_local_level(l, mk_param_univ(l));
-            ps.push_back(l);
-        }
-        p.next();
-    }
-}
-
-static void update_parameters(buffer<name> & ls_buffer, name_set const & found, parser const & p) {
-    unsigned old_sz = ls_buffer.size();
-    found.for_each([&](name const & n) {
-            if (std::find(ls_buffer.begin(), ls_buffer.begin() + old_sz, n) == ls_buffer.begin() + old_sz)
-                ls_buffer.push_back(n);
-        });
-    std::sort(ls_buffer.begin(), ls_buffer.end(), [&](name const & n1, name const & n2) {
-            return p.get_local_level_index(n1) < p.get_local_level_index(n2);
-        });
-}
-
-static environment declare_var(parser & p, environment env,
-                               name const & n, level_param_names const & ls, expr const & type,
-                               bool is_axiom, binder_info const & bi, pos_info const & pos) {
-    if (in_section(p.env())) {
-        p.add_local_expr(n, p.save_pos(mk_local(n, type), pos), bi);
-        return env;
-    } else {
-        name const & ns = get_namespace(env);
-        name full_n  = ns + n;
-        if (is_axiom)
-            env = module::add(env, check(env, mk_axiom(full_n, ls, type)));
-        else
-            env = module::add(env, check(env, mk_var_decl(full_n, ls, type)));
-        if (!ns.is_anonymous())
-            env = add_alias(env, n, mk_constant(full_n));
-        return env;
-    }
-}
-
-static environment variable_cmd_core(parser & p, bool is_axiom, binder_info const & bi) {
-    auto pos = p.pos();
-    name n = p.check_id_next("invalid declaration, identifier expected");
-    check_atomic(n);
-    buffer<name> ls_buffer;
-    if (p.curr_is_token(g_llevel_curly) && in_section(p.env()))
-        throw parser_error("invalid declaration, axioms/parameters occurring in sections cannot be universe polymorphic", p.pos());
-    optional<parser::local_scope> scope1;
-    if (!in_section(p.env()))
-        scope1.emplace(p);
-    parse_univ_params(p, ls_buffer);
-    parser::param_universe_scope scope2(p);
-    expr type;
-    if (!p.curr_is_token(g_colon)) {
-        buffer<parameter> ps;
-        auto lenv = p.parse_binders(ps);
-        p.check_token_next(g_colon, "invalid declaration, ':' expected");
-        type = p.parse_scoped_expr(ps, lenv);
-        type = p.pi_abstract(ps, type);
-    } else {
-        p.next();
-        type = p.parse_expr();
-    }
-    level_param_names ls;
-    if (in_section(p.env())) {
-        ls = to_level_param_names(collect_univ_params(type));
-    } else {
-        update_parameters(ls_buffer, collect_univ_params(type), p);
-        ls = to_list(ls_buffer.begin(), ls_buffer.end());
-    }
-    type = p.elaborate(type, ls);
-    return declare_var(p, p.env(), n, ls, type, is_axiom, bi, pos);
-}
-environment variable_cmd(parser & p) {
-    return variable_cmd_core(p, false, binder_info());
-}
-environment axiom_cmd(parser & p)    {
-    return variable_cmd_core(p, true, binder_info());
-}
-environment implicit_variable_cmd(parser & p) {
-    check_in_section(p);
-    return variable_cmd_core(p, false, mk_implicit_binder_info());
-}
-environment implicit_axiom_cmd(parser & p) {
-    check_in_section(p);
-    return variable_cmd_core(p, true, mk_implicit_binder_info());
-}
-environment cast_variable_cmd(parser & p) {
-    check_in_section(p);
-    return variable_cmd_core(p, false, mk_cast_binder_info());
-}
-
-static environment variables_cmd_core(parser & p, bool is_axiom, binder_info const & bi) {
-    auto pos = p.pos();
-    buffer<name> ids;
-    while (!p.curr_is_token(g_colon)) {
-        name id = p.check_id_next("invalid parameters declaration, identifier expected");
-        check_atomic(id);
-        ids.push_back(id);
-    }
-    p.next();
-    optional<parser::local_scope> scope1;
-    if (!in_section(p.env()))
-        scope1.emplace(p);
-    parser::param_universe_scope scope2(p);
-    expr type = p.parse_expr();
-    level_param_names ls = to_level_param_names(collect_univ_params(type));
-    type = p.elaborate(type, ls);
-    environment env = p.env();
-    for (auto id : ids)
-        env = declare_var(p, env, id, ls, type, is_axiom, bi, pos);
-    return env;
-}
-environment variables_cmd(parser & p) {
-    return variables_cmd_core(p, false, binder_info());
-}
-environment implicit_variables_cmd(parser & p) {
-    check_in_section(p);
-    return variables_cmd_core(p, false, mk_implicit_binder_info());
-}
-environment cast_variables_cmd(parser & p) {
-    check_in_section(p);
-    return variables_cmd_core(p, false, mk_cast_binder_info());
-}
-
-// Collect local (section) constants occurring in type and value, sort them, and store in section_ps
-static void collect_section_locals(expr const & type, expr const & value, parser const & p, buffer<parameter> & section_ps) {
-    name_set ls = collect_locals(type, collect_locals(value));
-    ls.for_each([&](name const & n) {
-            section_ps.push_back(*p.get_local(n));
-        });
-    std::sort(section_ps.begin(), section_ps.end(), [&](parameter const & p1, parameter const & p2) {
-            return p.get_local_index(mlocal_name(p1.m_local)) < p.get_local_index(mlocal_name(p2.m_local));
-        });
-}
-
-static void parse_modifiers(parser & p, bool & is_private, bool & is_opaque) {
-    while (true) {
-        if (p.curr_is_token(g_private)) {
-            is_private = true;
-            p.next();
-        } else if (p.curr_is_token(g_inline)) {
-            is_opaque = false;
-            p.next();
-        } else {
-            break;
-        }
-    }
-}
-
-// Wrap \c e with the "explicit macro", the idea is to inform the elaborator
-// preprocessor, that we do not need create metavariables for implicit arguments
-static expr mark_explicit(expr const & e) {
-    // TODO(Leo)
-    return e;
-}
-
-environment definition_cmd_core(parser & p, bool is_theorem, bool is_opaque) {
-    bool is_private = false;
-    parse_modifiers(p, is_private, is_opaque);
-    if (is_theorem && !is_opaque)
-        throw exception("invalid theorem declaration, theorems cannot be transparent");
-    name n = p.check_id_next("invalid declaration, identifier expected");
-    check_atomic(n);
-    environment env = p.env();
-    name real_n; // real name for this declaration
-    if (is_private) {
-        auto env_n = add_private_name(env, n, optional<unsigned>(hash(p.pos().first, p.pos().second)));
-        env    = env_n.first;
-        real_n = env_n.second;
-    } else {
-        name const & ns = get_namespace(env);
-        real_n     = ns + n;
-    }
-    buffer<name> ls_buffer;
-    expr type, value;
-    level_param_names ls;
-    {
-        parser::local_scope scope1(p);
-        parse_univ_params(p, ls_buffer);
-        if (!p.curr_is_token(g_colon)) {
-            buffer<parameter> ps;
-            optional<local_environment> lenv;
-            {
-                parser::param_universe_scope scope2(p);
-                lenv = p.parse_binders(ps);
-                p.check_token_next(g_colon, "invalid declaration, ':' expected");
-                type = p.parse_scoped_expr(ps, *lenv);
-            }
-            p.check_token_next(g_assign, "invalid declaration, ':=' expected");
-            value = p.parse_scoped_expr(ps, *lenv);
-            type = p.pi_abstract(ps, type);
-            value = p.lambda_abstract(ps, value);
-        } else {
-            p.next();
-            {
-                parser::param_universe_scope scope2(p);
-                type = p.parse_expr();
-            }
-            p.check_token_next(g_assign, "invalid declaration, ':=' expected");
-            value = p.parse_expr();
-        }
-        update_parameters(ls_buffer, collect_univ_params(value, collect_univ_params(type)), p);
-        ls = to_list(ls_buffer.begin(), ls_buffer.end());
-    }
-    if (in_section(env)) {
-        buffer<parameter> section_ps;
-        collect_section_locals(type, value, p, section_ps);
-        type = p.pi_abstract(section_ps, type);
-        value = p.lambda_abstract(section_ps, value);
-        buffer<level> section_ls_buffer;
-        for (name const & l : ls) {
-            if (p.get_local_level_index(l))
-                section_ls_buffer.push_back(mk_param_univ(l));
-            else
-                break;
-        }
-        levels section_ls = to_list(section_ls_buffer.begin(), section_ls_buffer.end());
-        buffer<expr> section_args;
-        for (auto const & p : section_ps)
-            section_args.push_back(p.m_local);
-        expr ref = mk_app(mark_explicit(mk_constant(real_n, section_ls)), section_args);
-        p.add_local_expr(n, ref);
-    } else {
-        if (real_n != n)
-            env = add_alias(env, n, mk_constant(real_n));
-    }
-    if (is_theorem) {
-        // TODO(Leo): delay theorems
-        auto type_value = p.elaborate(type, value, ls);
-        type  = type_value.first;
-        value = type_value.second;
-        env = module::add(env, check(env, mk_theorem(real_n, ls, type, value)));
-    } else {
-        auto type_value = p.elaborate(type, value, ls);
-        type  = type_value.first;
-        value = type_value.second;
-        env = module::add(env, check(env, mk_definition(env, real_n, ls, type, value, is_opaque)));
-    }
-    return env;
-}
-environment definition_cmd(parser & p) {
-    return definition_cmd_core(p, false, true);
-}
-environment abbreviation_cmd(parser & p) {
-    return definition_cmd_core(p, false, false);
-}
-environment theorem_cmd(parser & p) {
-    return definition_cmd_core(p, true, true);
-}
-
 environment print_cmd(parser & p) {
     if (p.curr() == scanner::token_kind::String) {
         p.regular_stream() << p.get_str_val() << endl;
@@ -495,23 +211,12 @@ cmd_table init_cmd_table() {
     add_cmd(r, cmd_info("set_option",   "set configuration option", set_option_cmd));
     add_cmd(r, cmd_info("exit",         "exit", exit_cmd));
     add_cmd(r, cmd_info("print",        "print a string", print_cmd));
-    add_cmd(r, cmd_info("universe",     "declare a global universe level", universe_cmd));
     add_cmd(r, cmd_info("section",      "open a new section", section_cmd));
     add_cmd(r, cmd_info("namespace",    "open a new namespace", namespace_cmd));
     add_cmd(r, cmd_info("end",          "close the current namespace/section", end_scoped_cmd));
-    add_cmd(r, cmd_info("variable",     "declare a new parameter", variable_cmd));
-    add_cmd(r, cmd_info("{variable}",   "declare a new implict parameter", implicit_variable_cmd));
-    add_cmd(r, cmd_info("[variable]",   "declare a new cast parameter", cast_variable_cmd));
-    add_cmd(r, cmd_info("axiom",        "declare a new axiom", axiom_cmd));
-    add_cmd(r, cmd_info("{axiom}",      "declare a new implicit axiom", implicit_axiom_cmd));
-    add_cmd(r, cmd_info("variables",    "declare new parameters", variables_cmd));
-    add_cmd(r, cmd_info("{variables}",  "declare new implict parameters", implicit_variables_cmd));
-    add_cmd(r, cmd_info("[variables]",  "declare new cast parameters", cast_variables_cmd));
-    add_cmd(r, cmd_info("definition",   "add new definition", definition_cmd));
-    add_cmd(r, cmd_info("abbreviation", "add new abbreviation (aka transparent definition)", abbreviation_cmd));
-    add_cmd(r, cmd_info("theorem",      "add new theorem", theorem_cmd));
     add_cmd(r, cmd_info("check",        "type check given expression, and display its type", check_cmd));
     add_cmd(r, cmd_info("#setline",     "modify the current line number, it only affects error/report messages", set_line_cmd));
+    register_decl_cmds(r);
     register_notation_cmds(r);
     register_calc_cmds(r);
     return r;
diff --git a/src/frontends/lean/calc.cpp b/src/frontends/lean/calc.cpp
index 8bb771ae8..ee56a1d4b 100644
--- a/src/frontends/lean/calc.cpp
+++ b/src/frontends/lean/calc.cpp
@@ -18,6 +18,7 @@ Author: Leonardo de Moura
 #include "library/choice.h"
 #include "library/placeholder.h"
 #include "frontends/lean/parser.h"
+#include "frontends/lean/util.h"
 
 namespace lean {
 struct calc_ext : public environment_extension {
@@ -211,7 +212,7 @@ static void decode_expr(expr const & e, buffer<calc_pred> & preds, pos_info cons
 
 // Create (op _ _ ... _)
 static expr mk_op_fn(parser & p, name const & op, unsigned num_placeholders, pos_info const & pos) {
-    expr r = p.save_pos(mk_constant(op), pos);
+    expr r = p.save_pos(mark_explicit(mk_constant(op)), pos);
     while (num_placeholders > 0) {
         num_placeholders--;
         r = p.mk_app(r, p.save_pos(mk_expr_placeholder(), pos), pos);
diff --git a/src/frontends/lean/decl_cmds.cpp b/src/frontends/lean/decl_cmds.cpp
new file mode 100644
index 000000000..00ffe8811
--- /dev/null
+++ b/src/frontends/lean/decl_cmds.cpp
@@ -0,0 +1,301 @@
+/*
+Copyright (c) 2014 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura
+*/
+#include <algorithm>
+#include "util/sstream.h"
+#include "kernel/type_checker.h"
+#include "library/scoped_ext.h"
+#include "library/aliases.h"
+#include "library/private.h"
+#include "library/locals.h"
+#include "frontends/lean/parser.h"
+#include "frontends/lean/util.h"
+
+namespace lean {
+static name g_llevel_curly(".{");
+static name g_rcurly("}");
+static name g_colon(":");
+static name g_assign(":=");
+static name g_private("[private]");
+static name g_inline("[inline]");
+
+environment universe_cmd(parser & p) {
+    name n = p.check_id_next("invalid universe declaration, identifier expected");
+    check_atomic(n);
+    environment env = p.env();
+    if (in_section(env)) {
+        p.add_local_level(n, mk_param_univ(n));
+    } else {
+        name const & ns = get_namespace(env);
+        name full_n  = ns + n;
+        env = module::add_universe(env, full_n);
+        if (!ns.is_anonymous())
+            env = add_alias(env, n, mk_global_univ(full_n));
+    }
+    return env;
+}
+
+void parse_univ_params(parser & p, buffer<name> & ps) {
+    if (p.curr_is_token(g_llevel_curly)) {
+        p.next();
+        while (!p.curr_is_token(g_rcurly)) {
+            name l = p.check_id_next("invalid universe parameter, identifier expected");
+            p.add_local_level(l, mk_param_univ(l));
+            ps.push_back(l);
+        }
+        p.next();
+    }
+}
+
+void update_parameters(buffer<name> & ls_buffer, name_set const & found, parser const & p) {
+    unsigned old_sz = ls_buffer.size();
+    found.for_each([&](name const & n) {
+            if (std::find(ls_buffer.begin(), ls_buffer.begin() + old_sz, n) == ls_buffer.begin() + old_sz)
+                ls_buffer.push_back(n);
+        });
+    std::sort(ls_buffer.begin(), ls_buffer.end(), [&](name const & n1, name const & n2) {
+            return p.get_local_level_index(n1) < p.get_local_level_index(n2);
+        });
+}
+
+static environment declare_var(parser & p, environment env,
+                               name const & n, level_param_names const & ls, expr const & type,
+                               bool is_axiom, binder_info const & bi, pos_info const & pos) {
+    if (in_section(p.env())) {
+        p.add_local_expr(n, p.save_pos(mk_local(n, type), pos), bi);
+        return env;
+    } else {
+        name const & ns = get_namespace(env);
+        name full_n  = ns + n;
+        if (is_axiom)
+            env = module::add(env, check(env, mk_axiom(full_n, ls, type)));
+        else
+            env = module::add(env, check(env, mk_var_decl(full_n, ls, type)));
+        if (!ns.is_anonymous())
+            env = add_alias(env, n, mk_constant(full_n));
+        return env;
+    }
+}
+
+environment variable_cmd_core(parser & p, bool is_axiom, binder_info const & bi) {
+    auto pos = p.pos();
+    name n = p.check_id_next("invalid declaration, identifier expected");
+    check_atomic(n);
+    buffer<name> ls_buffer;
+    if (p.curr_is_token(g_llevel_curly) && in_section(p.env()))
+        throw parser_error("invalid declaration, axioms/parameters occurring in sections cannot be universe polymorphic", p.pos());
+    optional<parser::local_scope> scope1;
+    if (!in_section(p.env()))
+        scope1.emplace(p);
+    parse_univ_params(p, ls_buffer);
+    parser::param_universe_scope scope2(p);
+    expr type;
+    if (!p.curr_is_token(g_colon)) {
+        buffer<parameter> ps;
+        auto lenv = p.parse_binders(ps);
+        p.check_token_next(g_colon, "invalid declaration, ':' expected");
+        type = p.parse_scoped_expr(ps, lenv);
+        type = p.pi_abstract(ps, type);
+    } else {
+        p.next();
+        type = p.parse_expr();
+    }
+    level_param_names ls;
+    if (in_section(p.env())) {
+        ls = to_level_param_names(collect_univ_params(type));
+    } else {
+        update_parameters(ls_buffer, collect_univ_params(type), p);
+        ls = to_list(ls_buffer.begin(), ls_buffer.end());
+    }
+    type = p.elaborate(type, ls);
+    return declare_var(p, p.env(), n, ls, type, is_axiom, bi, pos);
+}
+environment variable_cmd(parser & p) {
+    return variable_cmd_core(p, false, binder_info());
+}
+environment axiom_cmd(parser & p)    {
+    return variable_cmd_core(p, true, binder_info());
+}
+environment implicit_variable_cmd(parser & p) {
+    check_in_section(p);
+    return variable_cmd_core(p, false, mk_implicit_binder_info());
+}
+environment implicit_axiom_cmd(parser & p) {
+    check_in_section(p);
+    return variable_cmd_core(p, true, mk_implicit_binder_info());
+}
+environment cast_variable_cmd(parser & p) {
+    check_in_section(p);
+    return variable_cmd_core(p, false, mk_cast_binder_info());
+}
+
+// Collect local (section) constants occurring in type and value, sort them, and store in section_ps
+void collect_section_locals(expr const & type, expr const & value, parser const & p, buffer<parameter> & section_ps) {
+    name_set ls = collect_locals(type, collect_locals(value));
+    ls.for_each([&](name const & n) {
+            section_ps.push_back(*p.get_local(n));
+        });
+    std::sort(section_ps.begin(), section_ps.end(), [&](parameter const & p1, parameter const & p2) {
+            return p.get_local_index(mlocal_name(p1.m_local)) < p.get_local_index(mlocal_name(p2.m_local));
+        });
+}
+
+static void parse_modifiers(parser & p, bool & is_private, bool & is_opaque) {
+    while (true) {
+        if (p.curr_is_token(g_private)) {
+            is_private = true;
+            p.next();
+        } else if (p.curr_is_token(g_inline)) {
+            is_opaque = false;
+            p.next();
+        } else {
+            break;
+        }
+    }
+}
+
+environment definition_cmd_core(parser & p, bool is_theorem, bool is_opaque) {
+    bool is_private = false;
+    parse_modifiers(p, is_private, is_opaque);
+    if (is_theorem && !is_opaque)
+        throw exception("invalid theorem declaration, theorems cannot be transparent");
+    name n = p.check_id_next("invalid declaration, identifier expected");
+    check_atomic(n);
+    environment env = p.env();
+    name real_n; // real name for this declaration
+    if (is_private) {
+        auto env_n = add_private_name(env, n, optional<unsigned>(hash(p.pos().first, p.pos().second)));
+        env    = env_n.first;
+        real_n = env_n.second;
+    } else {
+        name const & ns = get_namespace(env);
+        real_n     = ns + n;
+    }
+    buffer<name> ls_buffer;
+    expr type, value;
+    level_param_names ls;
+    {
+        parser::local_scope scope1(p);
+        parse_univ_params(p, ls_buffer);
+        if (!p.curr_is_token(g_colon)) {
+            buffer<parameter> ps;
+            optional<local_environment> lenv;
+            {
+                parser::param_universe_scope scope2(p);
+                lenv = p.parse_binders(ps);
+                p.check_token_next(g_colon, "invalid declaration, ':' expected");
+                type = p.parse_scoped_expr(ps, *lenv);
+            }
+            p.check_token_next(g_assign, "invalid declaration, ':=' expected");
+            value = p.parse_scoped_expr(ps, *lenv);
+            type = p.pi_abstract(ps, type);
+            value = p.lambda_abstract(ps, value);
+        } else {
+            p.next();
+            {
+                parser::param_universe_scope scope2(p);
+                type = p.parse_expr();
+            }
+            p.check_token_next(g_assign, "invalid declaration, ':=' expected");
+            value = p.parse_expr();
+        }
+        update_parameters(ls_buffer, collect_univ_params(value, collect_univ_params(type)), p);
+        ls = to_list(ls_buffer.begin(), ls_buffer.end());
+    }
+    if (in_section(env)) {
+        buffer<parameter> section_ps;
+        collect_section_locals(type, value, p, section_ps);
+        type = p.pi_abstract(section_ps, type);
+        value = p.lambda_abstract(section_ps, value);
+        buffer<level> section_ls_buffer;
+        for (name const & l : ls) {
+            if (p.get_local_level_index(l))
+                section_ls_buffer.push_back(mk_param_univ(l));
+            else
+                break;
+        }
+        levels section_ls = to_list(section_ls_buffer.begin(), section_ls_buffer.end());
+        buffer<expr> section_args;
+        for (auto const & p : section_ps)
+            section_args.push_back(p.m_local);
+        expr ref = mk_app(mark_explicit(mk_constant(real_n, section_ls)), section_args);
+        p.add_local_expr(n, ref);
+    } else {
+        if (real_n != n)
+            env = add_alias(env, n, mk_constant(real_n));
+    }
+    if (is_theorem) {
+        // TODO(Leo): delay theorems
+        auto type_value = p.elaborate(type, value, ls);
+        type  = type_value.first;
+        value = type_value.second;
+        env = module::add(env, check(env, mk_theorem(real_n, ls, type, value)));
+    } else {
+        auto type_value = p.elaborate(type, value, ls);
+        type  = type_value.first;
+        value = type_value.second;
+        env = module::add(env, check(env, mk_definition(env, real_n, ls, type, value, is_opaque)));
+    }
+    return env;
+}
+environment definition_cmd(parser & p) {
+    return definition_cmd_core(p, false, true);
+}
+environment abbreviation_cmd(parser & p) {
+    return definition_cmd_core(p, false, false);
+}
+environment theorem_cmd(parser & p) {
+    return definition_cmd_core(p, true, true);
+}
+
+static environment variables_cmd_core(parser & p, bool is_axiom, binder_info const & bi) {
+    auto pos = p.pos();
+    buffer<name> ids;
+    while (!p.curr_is_token(g_colon)) {
+        name id = p.check_id_next("invalid parameters declaration, identifier expected");
+        check_atomic(id);
+        ids.push_back(id);
+    }
+    p.next();
+    optional<parser::local_scope> scope1;
+    if (!in_section(p.env()))
+        scope1.emplace(p);
+    parser::param_universe_scope scope2(p);
+    expr type = p.parse_expr();
+    level_param_names ls = to_level_param_names(collect_univ_params(type));
+    type = p.elaborate(type, ls);
+    environment env = p.env();
+    for (auto id : ids)
+        env = declare_var(p, env, id, ls, type, is_axiom, bi, pos);
+    return env;
+}
+environment variables_cmd(parser & p) {
+    return variables_cmd_core(p, false, binder_info());
+}
+environment implicit_variables_cmd(parser & p) {
+    check_in_section(p);
+    return variables_cmd_core(p, false, mk_implicit_binder_info());
+}
+environment cast_variables_cmd(parser & p) {
+    check_in_section(p);
+    return variables_cmd_core(p, false, mk_cast_binder_info());
+}
+
+void register_decl_cmds(cmd_table & r) {
+    add_cmd(r, cmd_info("universe",     "declare a global universe level", universe_cmd));
+    add_cmd(r, cmd_info("variable",     "declare a new parameter", variable_cmd));
+    add_cmd(r, cmd_info("{variable}",   "declare a new implict parameter", implicit_variable_cmd));
+    add_cmd(r, cmd_info("[variable]",   "declare a new cast parameter", cast_variable_cmd));
+    add_cmd(r, cmd_info("axiom",        "declare a new axiom", axiom_cmd));
+    add_cmd(r, cmd_info("{axiom}",      "declare a new implicit axiom", implicit_axiom_cmd));
+    add_cmd(r, cmd_info("definition",   "add new definition", definition_cmd));
+    add_cmd(r, cmd_info("abbreviation", "add new abbreviation (aka transparent definition)", abbreviation_cmd));
+    add_cmd(r, cmd_info("theorem",      "add new theorem", theorem_cmd));
+    add_cmd(r, cmd_info("variables",    "declare new parameters", variables_cmd));
+    add_cmd(r, cmd_info("{variables}",  "declare new implict parameters", implicit_variables_cmd));
+    add_cmd(r, cmd_info("[variables]",  "declare new cast parameters", cast_variables_cmd));
+}
+}
diff --git a/src/frontends/lean/decl_cmds.h b/src/frontends/lean/decl_cmds.h
new file mode 100644
index 000000000..2ee286d34
--- /dev/null
+++ b/src/frontends/lean/decl_cmds.h
@@ -0,0 +1,17 @@
+/*
+Copyright (c) 2014 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/buffer.h"
+#include "kernel/expr.h"
+#include "frontends/lean/cmd_table.h"
+namespace lean {
+class parser;
+void parse_univ_params(parser & p, buffer<name> & ps);
+void update_parameters(buffer<name> & ls_buffer, name_set const & found, parser const & p);
+void collect_section_locals(expr const & type, expr const & value, parser const & p, buffer<parameter> & section_ps);
+void register_decl_cmds(cmd_table & r);
+}
diff --git a/src/frontends/lean/util.cpp b/src/frontends/lean/util.cpp
new file mode 100644
index 000000000..0f2d77431
--- /dev/null
+++ b/src/frontends/lean/util.cpp
@@ -0,0 +1,28 @@
+/*
+Copyright (c) 2014 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura
+*/
+#include "util/sstream.h"
+#include "library/scoped_ext.h"
+#include "frontends/lean/parser.h"
+
+namespace lean {
+void check_atomic(name const & n) {
+    if (!n.is_atomic())
+        throw exception(sstream() << "invalid declaration name '" << n << "', identifier must be atomic");
+}
+
+void check_in_section(parser const & p) {
+    if (!in_section(p.env()))
+        throw exception(sstream() << "invalid command, it must be used in a section");
+}
+
+// Wrap \c e with the "explicit macro", the idea is to inform the elaborator
+// preprocessor, that we do not need create metavariables for implicit arguments
+expr mark_explicit(expr const & e) {
+    // TODO(Leo)
+    return e;
+}
+}
diff --git a/src/frontends/lean/util.h b/src/frontends/lean/util.h
new file mode 100644
index 000000000..58c5e1a51
--- /dev/null
+++ b/src/frontends/lean/util.h
@@ -0,0 +1,14 @@
+/*
+Copyright (c) 2014 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+
+Author: Leonardo de Moura
+*/
+#pragma once
+#include "kernel/expr.h"
+namespace lean {
+class parser;
+void check_atomic(name const & n);
+void check_in_section(parser const & p);
+expr mark_explicit(expr const & e);
+}