feat(library/definition): macro definition and application Lua API

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

src/library/kernel_bindings.cpp

@@ -202,6 +202,13 @@ expr & to_binder(lua_State * L, int idx) {
     return r;
 }
 
+expr & to_macro_app(lua_State * L, int idx) {
+    expr & r = to_expr(L, idx);
+    if (!is_macro(r))
+        throw exception(sstream() << "arg #" << idx << " must be a macro application");
+    return r;
+}
+
 static int expr_tostring(lua_State * L) {
     std::ostringstream out;
     formatter fmt   = get_global_formatter(L);
@@ -334,8 +341,7 @@ static int expr_fields(lua_State * L) {
     case expr_kind::Sort:
         return push_level(L, sort_level(e));
     case expr_kind::Macro:
-        // TODO(Leo)
-        return 0;
+        return push_macro_definition(L, macro_def(e));
     case expr_kind::App:
         push_expr(L, app_fn(e)); push_expr(L, app_arg(e)); return 2;
     case expr_kind::Lambda:
@@ -441,6 +447,15 @@ static int expr_hash(lua_State * L) { return pushinteger(L, to_expr(L, 1).hash()
 static int expr_depth(lua_State * L) { return pushinteger(L, get_depth(to_expr(L, 1))); }
 static int expr_is_lt(lua_State * L) { return pushboolean(L, is_lt(to_expr(L, 1), to_expr(L, 2), false)); }
 
+static int expr_mk_macro(lua_State * L) {
+    buffer<expr> args;
+    copy_lua_array(L, 2, args);
+    return push_expr(L, mk_macro(to_macro_definition(L, 1), args.size(), args.data()));
+}
+
+static int macro_def(lua_State * L) { return push_macro_definition(L, macro_def(to_macro_app(L, 1))); }
+static int macro_num_args(lua_State * L) { return pushinteger(L, macro_num_args(to_macro_app(L, 1))); }
+static int macro_arg(lua_State * L) { return push_expr(L, macro_arg(to_macro_app(L, 1), pushinteger(L, 2))); }
 
 static const struct luaL_Reg expr_m[] = {
     {"__gc",             expr_gc}, // never throws
@@ -475,6 +490,9 @@ static const struct luaL_Reg expr_m[] = {
     {"binder_domain",    safe_function<binder_domain>},
     {"binder_body",      safe_function<binder_body>},
     {"binder_info",      safe_function<binder_info>},
+    {"macro_def",        safe_function<macro_def>},
+    {"macro_num_args",   safe_function<macro_num_args>},
+    {"macro_arg",        safe_function<macro_arg>},
     {"for_each",         safe_function<expr_for_each>},
     {"has_free_var",     safe_function<expr_has_free_var>},
     {"lift_free_vars",   safe_function<expr_lift_free_vars>},
@@ -508,6 +526,7 @@ static void open_expr(lua_State * L) {
     SET_GLOBAL_FUN(expr_mk_pi,       "mk_pi");
     SET_GLOBAL_FUN(expr_mk_arrow,    "mk_arrow");
     SET_GLOBAL_FUN(expr_mk_let,      "mk_let");
+    SET_GLOBAL_FUN(expr_mk_macro,    "mk_macro");
     SET_GLOBAL_FUN(expr_fun,         "fun");
     SET_GLOBAL_FUN(expr_fun,         "Fun");
     SET_GLOBAL_FUN(expr_pi,          "Pi");
@@ -536,6 +555,39 @@ static void open_expr(lua_State * L) {
     SET_ENUM("Macro",    expr_kind::Macro);
     lua_setglobal(L, "expr_kind");
 }
+// macro_definition
+DECL_UDATA(macro_definition)
+
+int macro_get_name(lua_State * L) { return push_name(L, to_macro_definition(L, 1).get_name()); }
+int macro_trust_level(lua_State * L) { return pushinteger(L, to_macro_definition(L, 1).trust_level()); }
+int macro_eq(lua_State * L) { return pushboolean(L, to_macro_definition(L, 1) == to_macro_definition(L, 2)); }
+int macro_hash(lua_State * L) { return pushinteger(L, to_macro_definition(L, 1).hash()); }
+static int macro_tostring(lua_State * L) {
+    std::ostringstream out;
+    formatter fmt   = get_global_formatter(L);
+    options opts    = get_global_options(L);
+    out << mk_pair(to_macro_definition(L, 1).pp(fmt, opts), opts);
+    return pushstring(L, out.str().c_str());
+}
+
+static const struct luaL_Reg macro_definition_m[] = {
+    {"__gc",             macro_definition_gc}, // never throws
+    {"__tostring",       safe_function<macro_tostring>},
+    {"__eq",             safe_function<macro_eq>},
+    {"hash",             safe_function<macro_hash>},
+    {"trust_level",      safe_function<macro_trust_level>},
+    {"name",             safe_function<macro_get_name>},
+    {0, 0}
+};
+
+void open_macro_definition(lua_State * L) {
+    luaL_newmetatable(L, macro_definition_mt);
+    lua_pushvalue(L, -1);
+    lua_setfield(L, -2, "__index");
+    setfuncs(L, macro_definition_m, 0);
+
+    SET_GLOBAL_FUN(macro_definition_pred, "is_macro_definition");
+}
 
 // Formatter
 DECL_UDATA(formatter)
@@ -1051,6 +1103,7 @@ void open_kernel_module(lua_State * L) {
     open_binder_info(L);
     open_expr(L);
     open_list_expr(L);
+    open_macro_definition(L);
     open_formatter(L);
     open_environment(L);
     open_io_state(L);

src/library/kernel_bindings.h

@@ -14,6 +14,7 @@ UDATA_DEFS(level)
 UDATA_DEFS(expr)
 UDATA_DEFS(formatter)
 UDATA_DEFS(definition)
+UDATA_DEFS(macro_definition)
 UDATA_DEFS(environment)
 UDATA_DEFS(substitution)
 UDATA_DEFS(justification)