first and rest function have been added

src/main/java/serene/simple/DefSpecialForm.java

@@ -29,6 +29,6 @@ public class DefSpecialForm extends SpecialForm {
     SymbolNode sym = (SymbolNode) this.node.rest().first();
     scope.insertSymbol(sym.name,
                        this.node.rest().rest().first().eval(scope));
-    return ListNode.EMPTY;
+    return null;
   }
 }

src/main/java/serene/simple/RootScope.java

@@ -46,7 +46,8 @@ public class RootScope extends AScope {
       put("conj", new ConjFn());
       put("list", new ListFn());
       put("first", new FirstFn());
-      // put("let", new LetFn());
+      put("rest", new RestFn());
+      //put("let", new LetFn());
       // put("cond", new CondFn());
       //put("reduce", new ReduceFn());
       put("System", System.class);

src/main/java/serene/simple/builtin/FirstFn.java

@@ -0,0 +1,47 @@
+/**
+ * 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 serene.simple.IScope;
+import serene.simple.ListNode;
+import serene.simple.SereneException;
+
+
+public class FirstFn extends AFn {
+  public String fnName() {
+    return "first";
+  };
+
+  public Object eval(IScope scope) throws SereneException{
+    List<Object> args = this.arguments();
+
+    if (args.size() == 0) {
+      throw new SereneException("First of what ?");
+    }
+
+    if (args.size() > 1) {
+      throw new SereneException("Too many parameters to 'first'.");
+    }
+
+    return ((ListNode<Object>) args.get(0)).first();
+  }
+}

src/main/java/serene/simple/builtin/RestFn.java

@@ -0,0 +1,47 @@
+/**
+ * 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 serene.simple.IScope;
+import serene.simple.ListNode;
+import serene.simple.SereneException;
+
+
+public class RestFn extends AFn {
+  public String fnName() {
+    return "rest";
+  };
+
+  public Object eval(IScope scope) throws SereneException{
+    List<Object> args = this.arguments();
+
+    if (args.size() == 0) {
+      throw new SereneException("Rest of what ?");
+    }
+
+    if (args.size() > 1) {
+      throw new SereneException("Too many parameters to 'rest'.");
+    }
+
+    return ((ListNode<Object>) args.get(0)).rest();
+  }
+}