net.hydromatic.morel.compile.RefChecker Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of morel Show documentation

Standard ML interpreter, with relational extensions, implemented in Java

There is a newer version: 0.7.0

/*
 * Licensed to Julian Hyde under one or more contributor license
 * agreements.  See the NOTICE file distributed with this work
 * for additional information regarding copyright ownership.
 * Julian Hyde licenses this file to you 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 net.hydromatic.morel.compile;

import net.hydromatic.morel.ast.Core;
import net.hydromatic.morel.type.TypeSystem;

import java.util.ArrayDeque;
import java.util.Deque;

import static com.google.common.base.Verify.verifyNotNull;

/** Validates expressions, making sure that every {@link Core.Id}
 * exists in the environment. */
public class RefChecker extends EnvVisitor {
  /** Creates a reference checker. */
  public static RefChecker of(TypeSystem typeSystem, Environment env) {
    return new RefChecker(typeSystem, env, new ArrayDeque<>());
  }

  private RefChecker(TypeSystem typeSystem, Environment env,
      Deque fromStack) {
    super(typeSystem, env, fromStack);
  }

  @Override protected RefChecker push(Environment env) {
    return new RefChecker(typeSystem, env, fromStack);
  }

  @Override protected void visit(Core.Id id) {
    verifyNotNull(env.getOpt(id.idPat), "not found", id);
  }
}

// End RefChecker.java