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Venice, a Lisp implemented in Java

There is a newer version: 1.12.38

/*   __    __         _
 *   \ \  / /__ _ __ (_) ___ ___
 *    \ \/ / _ \ '_ \| |/ __/ _ \
 *     \  /  __/ | | | | (_|  __/
 *      \/ \___|_| |_|_|\___\___|
 *
 *
 * Copyright 2017-2024 Venice
 *
 * 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 com.github.jlangch.venice.impl.reader;

import java.util.Deque;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentLinkedDeque;

import com.github.jlangch.venice.VncException;
import com.github.jlangch.venice.impl.env.GenSym;
import com.github.jlangch.venice.impl.types.VncSymbol;


public class AutoGenSym {

    public AutoGenSym() {
    }

    public void enterSyntaxQuote() {
        stack.push(new HashMap());
    }

    public void leaveSyntaxQuote() {
        stack.pop();
    }

    public boolean isWithinSyntaxQuote() {
        return !stack.isEmpty();
    }

    public boolean isAutoGenSymbol(final VncSymbol sym) {
        final String name = sym.getName();
        return name.length() > 1 && name.endsWith("#");
    }

    public VncSymbol lookup(final VncSymbol sym) {
        if (stack.isEmpty()) {
            throw new VncException(String.format(
                    "Invalid autogen symbol (%s) usage outside of a syntax quote!",
                    sym.getName()));
        }

        final Map autogenSymMap = stack.peek();

        return isAutoGenSymbol(sym)
                    ? autogenSymMap.computeIfAbsent(sym, s -> genAutoSym(s))
                    : sym;
    }

    private VncSymbol genAutoSym(final VncSymbol sym) {
        return GenSym.generateAutoSym(stripTrailingHash(sym.getName()));
    }

    private String stripTrailingHash(final String s) {
        return s.substring(0, s.length()-1);
    }


    // A stack that maps "xyz#" -> "xyz__1000__auto"
    private final Deque> stack = new ConcurrentLinkedDeque<>();
}