feat: toStringRepr to map to luaL_tolstring

Author: mworzala

build.gradle.kts

@@ -241,6 +241,8 @@ tasks.named<JextractTask>("jextract") {
             "luaL_checkbuffer", "luaL_checkstack", "luaL_checktype",
             "luaL_checkany", "luaL_checkudata", "luaL_checkoption",
 
+            "luaL_tolstring",
+
             "luaL_where",
 
             "luaopen_base", "luaopen_coroutine", "luaopen_table",

src/generated/java/net/hollowcube/luau/internal/vm/lua_h.java

@@ -5755,7 +5755,7 @@ public double apply(Object... x0) {
                 if (TRACE_DOWNCALLS) {
                     traceDowncall("lua_clock", x0);
                 }
-                return (double) spreader.invokeExact(x0);
+                return (double)spreader.invokeExact(x0);
             } catch(IllegalArgumentException | ClassCastException ex$)  {
                 throw ex$; // rethrow IAE from passing wrong number/type of args
             } catch (Throwable ex$) {

src/generated/java/net/hollowcube/luau/internal/vm/lualib_h.java

@@ -1556,6 +1556,66 @@ public static int luaL_checkoption(MemorySegment L, int narg, MemorySegment def,
         }
     }
 
+    private static class luaL_tolstring {
+        public static final FunctionDescriptor DESC = FunctionDescriptor.of(
+            lualib_h.C_POINTER,
+            lualib_h.C_POINTER,
+            lualib_h.C_INT,
+            lualib_h.C_POINTER
+        );
+
+        public static final MemorySegment ADDR = lualib_h.findOrThrow("luaL_tolstring");
+
+        public static final MethodHandle HANDLE = Linker.nativeLinker().downcallHandle(ADDR, DESC);
+    }
+
+    /**
+     * Function descriptor for:
+     * {@snippet lang=c :
+     * extern const char *luaL_tolstring(lua_State *L, int idx, size_t *len)
+     * }
+     */
+    public static FunctionDescriptor luaL_tolstring$descriptor() {
+        return luaL_tolstring.DESC;
+    }
+
+    /**
+     * Downcall method handle for:
+     * {@snippet lang=c :
+     * extern const char *luaL_tolstring(lua_State *L, int idx, size_t *len)
+     * }
+     */
+    public static MethodHandle luaL_tolstring$handle() {
+        return luaL_tolstring.HANDLE;
+    }
+
+    /**
+     * Address for:
+     * {@snippet lang=c :
+     * extern const char *luaL_tolstring(lua_State *L, int idx, size_t *len)
+     * }
+     */
+    public static MemorySegment luaL_tolstring$address() {
+        return luaL_tolstring.ADDR;
+    }
+
+    /**
+     * {@snippet lang=c :
+     * extern const char *luaL_tolstring(lua_State *L, int idx, size_t *len)
+     * }
+     */
+    public static MemorySegment luaL_tolstring(MemorySegment L, int idx, MemorySegment len) {
+        var mh$ = luaL_tolstring.HANDLE;
+        try {
+            if (TRACE_DOWNCALLS) {
+                traceDowncall("luaL_tolstring", L, idx, len);
+            }
+            return (MemorySegment)mh$.invokeExact(L, idx, len);
+        } catch (Throwable ex$) {
+           throw new AssertionError("should not reach here", ex$);
+        }
+    }
+
     private static class luaL_newstate {
         public static final FunctionDescriptor DESC = FunctionDescriptor.of(
             lualib_h.C_POINTER    );

src/main/java/net/hollowcube/luau/LuaState.java

@@ -124,6 +124,13 @@ Access Functions (Stack -> Java)
     @NotNull ByteBuffer toBuffer(int index); //todo type
     Object toPointer(int index); //todo type
 
+    /**
+     * Converts the value to its string representation, including calling __tostring metamethods.
+     *
+     * <p>Maps to luaL_tolstring.</p>
+     */
+    @NotNull String toStringRepr(int index);
+
     /*
     Push Functions (Java -> Stack)
      */
@@ -264,8 +271,8 @@ static double clock() {
      */
 
     int stackDepth();
-//    int getInfo(); //todo args here
-//    int getArgument(); //todo args here
+    //    int getInfo(); //todo args here
+    //    int getArgument(); //todo args here
     // getLocal
     // setLocal
     // getUpValue

src/main/java/net/hollowcube/luau/LuaStateImpl.java

@@ -83,7 +83,8 @@ public LuaStateImpl() {
     @Override
     public void close() {
         if (isThread)
-            throw new IllegalStateException("cannot close a thread directly, it will be closed when lua garbage collects it.");
+            throw new IllegalStateException(
+                    "cannot close a thread directly, it will be closed when lua garbage collects it.");
         lua_h.lua_close(L);
         closeInternal();
     }
@@ -427,6 +428,11 @@ public Object toPointer(int index) {
         throw new UnsupportedOperationException("todo");
     }
 
+    @Override
+    public @NotNull String toStringRepr(int index) {
+        return readLString(len -> luaL_tolstring(L, index, len));
+    }
+
     @Override
     public void pushNil() {
         lua_pushnil(L);