fix transformToFieldExp return behavior

src/kiss/KissInterp2.kiss

@@ -292,7 +292,7 @@
 							(cc f)
 							(return)))
 					// Check for field access
-					(whenLet [exp (transformToFieldExp exp)]
+					(whenLet [exp (transformToFieldExp exp true)]
 						(evalCC exp cc)
 						(return))
 					// Check for ident aliases
@@ -321,11 +321,12 @@
 		(cc outputs)))
 
 // Check if an identifier has field access in it, return true if transform it to FieldExp
-(method transformToFieldExp [:ReaderExp exp]
+(method transformToFieldExp [:ReaderExp exp &opt :Bool nullIfNot]
 	(case exp.def
 		((Symbol ident)
 			(let [idx (ident.indexOf ".")]
-				(unless (= -1 idx)
+				(if (= -1 idx)
+						(return (if nullIfNot null exp))
 					(let [parts (ident.split ".")
 							&mut newExp (makeExp (Symbol (first parts)))]
 						(doFor part (parts.slice 1)
@@ -333,4 +334,4 @@
 								(when safe (set part (part.substr 1)))
 								(set newExp (makeExp (FieldExp part newExp safe)))))
 						(return newExp)))))
-		(otherwise (return null))))
+		(otherwise (return (if nullIfNot null exp)))))