Create LuaMetaType

src/main/java/org/glavo/lua/runtime/LuaMetaType.java

@@ -0,0 +1,84 @@
+/*
+ * Copyright 2024 Glavo
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.glavo.lua.runtime;
+
+import com.oracle.truffle.api.CompilerDirectives;
+import com.oracle.truffle.api.TruffleLanguage;
+import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.TruffleObject;
+import com.oracle.truffle.api.library.CachedLibrary;
+import com.oracle.truffle.api.library.ExportLibrary;
+import com.oracle.truffle.api.library.ExportMessage;
+import org.glavo.lua.LuaLanguage;
+
+import java.util.function.BiPredicate;
+
+@ExportLibrary(InteropLibrary.class)
+public final class LuaMetaType implements TruffleObject {
+
+    public static final LuaMetaType NULL = new LuaMetaType("nil", InteropLibrary::isNull);
+    public static final LuaMetaType BOOLEAN = new LuaMetaType("boolean", InteropLibrary::isBoolean);
+    public static final LuaMetaType STRING = new LuaMetaType("string", InteropLibrary::isString);
+    public static final LuaMetaType NUMBER = new LuaMetaType("number", InteropLibrary::isNumber);
+    public static final LuaMetaType FUNCTION = new LuaMetaType("function", InteropLibrary::isExecutable);
+
+    private final String name;
+    private final BiPredicate<InteropLibrary, Object> typeCheck;
+
+    private LuaMetaType(String name, BiPredicate<InteropLibrary, Object> typeCheck) {
+        this.name = name;
+        this.typeCheck = typeCheck;
+    }
+
+    @ExportMessage
+    boolean hasLanguage() {
+        return true;
+    }
+
+    @ExportMessage
+    Class<? extends TruffleLanguage<?>> getLanguage() {
+        return LuaLanguage.class;
+    }
+
+    @ExportMessage
+    boolean isMetaObject() {
+        return true;
+    }
+
+    @ExportMessage
+    static class IsMetaInstance {
+        @Specialization(guards = "type == cachedType", limit = "3")
+        static boolean doCached(LuaMetaType type, Object value,
+                                @Cached("type") LuaMetaType cachedType,
+                                @CachedLibrary("value") InteropLibrary valueLib) {
+            return cachedType.typeCheck.test(valueLib, value);
+        }
+
+        @CompilerDirectives.TruffleBoundary
+        @Specialization(replaces = "doCached")
+        static boolean doGeneric(LuaMetaType type, Object value) {
+            return type.typeCheck.test(InteropLibrary.getUncached(), value);
+        }
+    }
+
+    @CompilerDirectives.TruffleBoundary
+    @Override
+    public String toString() {
+        return "LuaMetaType[" + name + "]";
+    }
+}