add not, with a reader macro

src/kiss/Reader.hx

@@ -48,6 +48,8 @@ class Reader {
 
         readTable["&"] = (stream) -> MetaExp(nextToken(stream, "a meta symbol like mut, optional, rest"));
 
+        readTable["!"] = (stream:Stream) -> CallExp(Symbol("not").withPos(stream.position()), [assertRead(stream, readTable)]);
+
         // Because macro keys are sorted by length and peekChars(0) returns "", this will be used as the default reader macro:
         readTable[""] = (stream) -> Symbol(nextToken(stream, "a symbol name"));
 

src/kiss/SpecialForms.hx

@@ -195,6 +195,14 @@ class SpecialForms {
                 $elseExp;
         };
 
+        map["not"] = (args:Array<ReaderExp>, convert:ExprConversion) -> {
+            if (args.length != 1)
+                throw '(not... ) only takes one argument, not $args';
+            var condition = convert(args[0]);
+            var truthyExp = macro Prelude.truthy($condition);
+            macro !$truthyExp;
+        };
+
         return map;
     }
 

src/test/cases/BasicTestCase.hx

@@ -173,4 +173,9 @@ class BasicTestCase extends Test {
     function testOr() {
         Assert.equals(5, BasicTestCase.myOr1);
     }
+
+    function testNot() {
+        Assert.equals(false, BasicTestCase.myNot1);
+        Assert.equals(false, BasicTestCase.myNot2);
+    }
 }

src/test/cases/BasicTestCase.kiss

@@ -133,4 +133,7 @@
 (defun mySetLocal []
     (deflocal loc &mut "one thing")
     (set loc "another thing")
-    loc)
+    loc)
+
+(defvar myNot1 (not 5))
+(defvar myNot2 !5)