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Lua API: Some enhancements/fixes to named tuples.

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* Make named tuples comparable with == and ~=
* Fix the possibility of the numeric and string keys becoming out-of-syn on assignment
* Fix non-existent numeric keys being treated like a string key
This commit is contained in:
Celtic Minstrel 2024-09-23 00:55:05 -04:00
parent ca301e1745
commit 15062976ca
1 changed files with 57 additions and 2 deletions
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59
src/scripting/lua_common.cpp
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@ -676,7 +676,7 @@ void luaW_filltable(lua_State *L, const config& cfg)
static int impl_namedtuple_get(lua_State* L)
{
if(lua_isstring(L, 2)) {
if(lua_type(L, 2) == LUA_TSTRING) {
std::string k = lua_tostring(L, 2);
luaL_getmetafield(L, 1, "__names");
auto names = lua_check<std::vector<std::string>>(L, -1);
@ -690,6 +690,26 @@ static int impl_namedtuple_get(lua_State* L)
return 0;
}
static int impl_namedtuple_set(lua_State* L)
{
if(lua_type(L, 2) == LUA_TSTRING) {
std::string k = lua_tostring(L, 2);
luaL_getmetafield(L, 1, "__names");
auto names = lua_check<std::vector<std::string>>(L, -1);
auto iter = std::find(names.begin(), names.end(), k);
if(iter != names.end()) {
int i = std::distance(names.begin(), iter) + 1;
lua_pushvalue(L, 3);
lua_rawseti(L, 1, i);
return 0;
}
}
// If it's not one of the special names, just assign normally
lua_settop(L, 3);
lua_rawset(L, 1);
return 0;
}
static int impl_namedtuple_dir(lua_State* L)
{
luaL_getmetafield(L, 1, "__names");
@ -709,13 +729,46 @@ static int impl_namedtuple_tostring(lua_State* L)
return 1;
}
static int impl_namedtuple_compare(lua_State* L) {
// Comparing a named tuple with any other table is always false.
if(lua_type(L, 1) != LUA_TTABLE || lua_type(L, 2) != LUA_TTABLE) {
NOT_EQUAL:
lua_pushboolean(L, false);
return 1;
}
luaL_getmetafield(L, 1, "__name");
luaL_getmetafield(L, 2, "__name");
if(!lua_rawequal(L, 3, 4)) goto NOT_EQUAL;
lua_pop(L, 2);
// Named tuples can be equal only if they both have the exact same set of names.
luaL_getmetafield(L, 1, "__names");
luaL_getmetafield(L, 2, "__names");
auto lnames = lua_check<std::vector<std::string>>(L, 3);
auto rnames = lua_check<std::vector<std::string>>(L, 4);
if(lnames != rnames) goto NOT_EQUAL;
lua_pop(L, 2);
// They are equal if all of the corresponding members in each tuple are equal.
for(size_t i = 1; i <= lnames.size(); i++) {
lua_rawgeti(L, 1, i);
lua_rawgeti(L, 2, i);
if(!lua_compare(L, 3, 4, LUA_OPEQ)) goto NOT_EQUAL;
lua_pop(L, 2);
}
// Theoretically, they could have other members besides the special named ones.
// But we ignore those for the purposes of equality.
lua_pushboolean(L, true);
return 1;
}
void luaW_push_namedtuple(lua_State* L, const std::vector<std::string>& names)
{
lua_createtable(L, names.size(), 0);
lua_createtable(L, 0, 4);
lua_createtable(L, 0, 8);
static luaL_Reg callbacks[] = {
{ "__index", &impl_namedtuple_get },
{ "__newindex", &impl_namedtuple_set },
{ "__dir", &impl_namedtuple_dir },
{ "__eq", &impl_namedtuple_compare },
{ "__tostring", &impl_namedtuple_tostring },
{ nullptr, nullptr }
};
@ -734,6 +787,8 @@ void luaW_push_namedtuple(lua_State* L, const std::vector<std::string>& names)
lua_setfield(L, -2, "__metatable");
lua_push(L, names);
lua_setfield(L, -2, "__names");
lua_pushstring(L, "named tuple");
lua_setfield(L, -2, "__name");
lua_setmetatable(L, -2);
}