Make pairs and ipairs call the appropriate metamethods when present

As is done in Lua 5.2. This makes it possible to use ipairs on the
subtitles object.
This commit is contained in:
Thomas Goyne 2013-05-01 18:26:05 -07:00
parent a6f7375427
commit 995e0d85e9

View file

@ -149,6 +149,48 @@ namespace {
set_field(L, "set", clipboard_set);
return 1;
}
struct table_pairs {
static void init(lua_State *L) { lua_pushnil(L); }
static int next(lua_State *L) {
luaL_checktype(L, 1, LUA_TTABLE);
lua_settop(L, 2);
if (lua_next(L, 1))
return 2;
lua_pushnil(L);
return 1;
}
static const char *method() { return "__pairs"; }
};
struct table_ipairs {
static void init(lua_State *L) { push_value(L, 1); }
static int next(lua_State *L) {
luaL_checktype(L, 1, LUA_TTABLE);
int i = luaL_checkint(L, 2) + 1;
lua_pushinteger(L, i);
lua_rawgeti(L, 1, i);
return lua_isnil(L, -1) ? 1 : 2;
}
static const char *method() { return "__ipairs"; }
};
template<typename TableIter>
int pairs(lua_State *L) {
// If the metamethod is defined, call it instead
if (luaL_getmetafield(L, 1, TableIter::method())) {
lua_pushvalue(L, 1);
lua_call(L, 1, 3);
return 3;
}
// No metamethod, so use the table iterators
luaL_checktype(L, 1, LUA_TTABLE);
lua_pushcfunction(L, &TableIter::next);
lua_pushvalue(L, 1);
TableIter::init(L);
return 3;
}
}
namespace Automation4 {
@ -194,6 +236,12 @@ namespace Automation4 {
push_value(L, LuaInclude);
lua_setglobal(L, "include");
// replace pairs and ipairs with lua 5.2-style versions
push_value(L, &pairs<table_pairs>);
lua_setglobal(L, "pairs");
push_value(L, &pairs<table_ipairs>);
lua_setglobal(L, "ipairs");
// add include_path to the module load path
lua_getglobal(L, "package");
push_value(L, "path");