62 lines
1.9 KiB
Java
62 lines
1.9 KiB
Java
/**
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* Serene (simple) - A PoC lisp to collect data on Serenes concepts
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* Copyright (C) 2019-2020 Sameer Rahmani <lxsameer@gnu.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*/
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package serene.simple.builtin;
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import java.util.List;
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import serene.simple.IDoc;
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import serene.simple.IScope;
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import serene.simple.ListNode;
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import serene.simple.SereneException;
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public class ReverseFn extends AFn implements IDoc {
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public String fnName() {
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return "reverse";
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};
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public String getDoc() {
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return "`(reverse coll)`: Returns a new list by reversing the COLL.";
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}
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public Object eval(IScope scope) throws SereneException {
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List<Object> args = this.arguments();
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if (args.size() != 1) {
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throw new SereneException("'reverse' excepts 1 argument.");
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}
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else {
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if (args.get(0) instanceof ListNode) {
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ListNode<Object> l = (ListNode<Object>) args.get(0);
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int index = l.length;
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Object[] objs = new Object[index];
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for (Object x : l) {
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System.out.println(index);
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index--;
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objs[index] = x;
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}
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return ListNode.list(objs);
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}
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throw new SereneException("'reverse' argument should be list.");
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}
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}
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}
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