src/examples/Mini/ASTIdent.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF 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
 *
 *   https://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.
 */
/* Generated By:JJTree: Do not edit this line. ASTIdent.java */
/* JJT: 0.3pre1 */

package Mini;

import org.apache.bcel.Const;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.ILOAD;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.LocalVariableGen;
import org.apache.bcel.generic.MethodGen;
import org.apache.bcel.generic.PUSH;

/**
 */
public class ASTIdent extends ASTExpr {
    public static Node jjtCreate(final MiniParser p, final int id) {
        return new ASTIdent(p, id);
    }

    private String name;

    private Variable reference; // Reference in environment to decl of this ident

    // Generated methods
    ASTIdent(final int id) {
        super(id);
    }

    ASTIdent(final MiniParser p, final int id) {
        super(p, id);
    }

    public ASTIdent(final String name, final int type, final int line, final int column) {
        super(line, column, JJTIDENT);

        this.name = name;
        this.type = type;
    }

    // closeNode, dump inherited

    /**
     * Fifth pass, produce Java byte code.
     */
    @Override
    public void byte_code(final InstructionList il, final MethodGen method, final ConstantPoolGen cp) {
        if (name.equals("TRUE")) {
            il.append(new PUSH(cp, 1));
        } else if (name.equals("FALSE")) {
            il.append(new PUSH(cp, 0));
        } else {
            final LocalVariableGen local_var = reference.getLocalVariable();
            il.append(new ILOAD(local_var.getIndex()));
        }
        ASTFunDecl.push();
    }

    /**
     * Fourth pass, produce Java code.
     */
    @Override
    public void code(final StringBuffer buf) {
        if (name.equals("TRUE")) {
            ASTFunDecl.push(buf, "1");
        } else if (name.equals("FALSE")) {
            ASTFunDecl.push(buf, "0");
        } else {
            ASTFunDecl.push(buf, name);
        }
    }

    /**
     * Overrides AstExpr.eval()
     */
    @Override
    public int eval(final int expected) {
        final ASTIdent ident = reference.getName();
        final int t = ident.getType();

        is_simple = true; // (Very) simple expression, always true

        if (t == Const.T_UNKNOWN && expected == Const.T_UNKNOWN) {
            type = Const.T_UNKNOWN;
        } else if (t == Const.T_UNKNOWN && expected != Const.T_UNKNOWN) {
            ident.setType(expected);
            type = expected;
        } else {
            if (t != Const.T_UNKNOWN && expected == Const.T_UNKNOWN) {
                ident.setType(t);
            }
            type = t;
        }

        return type;
    }

    public String getName() {
        return name;
    }

    public void setName(final String name) {
        this.name = name;
    }

    /**
     * @return identifier and line/column number of appearance
     */
    @Override
    public String toString() {
        return super.toString() + " = " + name;
    }

    /**
     * Overrides ASTExpr.traverse()
     */
    @Override
    public ASTExpr traverse(final Environment env) {
        final EnvEntry entry = env.get(name);

        if (entry == null) {
            MiniC.addError(line, column, "Undeclared identifier " + name);
        } else if (entry instanceof Function) {
            MiniC.addError(line, column, "Function " + name + " used as an identifier.");
        } else {
            reference = (Variable) entry;
        }

        return this; // Nothing to reduce/traverse further here
    }
}