Native reduce function has been added

This commit is contained in:
Sameer Rahmani 2020-01-03 00:03:56 +00:00
parent ade2cff99d
commit e5d8a44ca8
3 changed files with 67 additions and 1 deletions

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@ -1,4 +1,4 @@
(def reduce
(def reduce1
(fn (f xs initial-value)
(cond
((first xs) (reduce f (rest xs) (f initial-value (first xs))))

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@ -51,6 +51,7 @@ public class RootScope extends AScope {
put("first", new FirstFn());
put("rest", new RestFn());
put("doc", new DocFn());
put("reduce", new ReduceFn());
put("System", System.class);
put("Boolean", Boolean.class);
put("String", String.class);

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@ -0,0 +1,65 @@
/**
* 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.builtin;
import java.util.List;
import java.util.function.Function;
import serene.simple.IDoc;
import serene.simple.IScope;
import serene.simple.ListNode;
import serene.simple.SereneException;
public class ReduceFn extends AFn implements IDoc {
public String fnName() {
return "reduce";
};
public String getDoc() {
return "(reduce f coll initial-value): Reduce the COLL by applying F.";
}
public Object eval(IScope scope) throws SereneException{
List<Object> args = this.arguments();
if (args.size() != 3) {
throw new SereneException(
String.format("reduce expects 3 parameters. Got %s", args.size()));
}
Function<Object,Object> fn = (Function<Object, Object>) args.get(0);
ListNode<Object> coll = (ListNode<Object>) args.get(1);
Object initialValue = args.get(2);
while(true) {
Object x = coll.first();
if (x == null)
break;
Object[] fnArgs = { initialValue, x };
coll = coll.rest();
initialValue = fn.apply(fnArgs);
}
return initialValue;
}
}