serene-simple/src/main/java/serene/simple/FnSpecialForm.java

69 lines
2.3 KiB
Java

/**
* Serene (simple) - A PoC lisp to collect data on Serenes concepts
* Copyright (C) 2019-2020 Sameer Rahmani <lxsameer@gnu.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
package serene.simple;
import java.util.function.Function;
public class FnSpecialForm extends SpecialForm {
public FnSpecialForm(ListNode<Node> paramsAndBody) {
super(paramsAndBody);
}
@Override
public Object eval(final BaseScope parentScope) {
final ListNode<Node> formalParams = (ListNode<Node>) this.node.rest().first();
final ListNode<Node> body = this.node.rest().rest();
return new Function<Object, Object>() {
@Override
public Object apply(Object arguments) {
Object[] args = (Object[]) arguments;
Scope scope = new Scope(parentScope);
if (args.length != formalParams.length) {
throw new RuntimeException(String.format("Wrong number of arguments. Expected: %s, Got: %s.",
formalParams.length,
args.length));
}
// Map parameter values to formal parameter names
int i = 0;
for (Node param : formalParams) {
SymbolNode paramSymbol = (SymbolNode) param;
scope.insertSymbol(paramSymbol.name, args[i]);
i++;
}
// Evaluate body
Object output = null;
for (Node node : body) {
output = node.eval(scope);
}
return output;
}
@Override
public String toString() {
return "Function@" + System.identityHashCode(this);
}
};
}
}