fix some KissInterp2 side-effects on exps

src/kiss/KissInterp2.kiss

@@ -47,7 +47,7 @@
 	=>"let"
 		->[args cc]
 			(let [bindings (first args)
-					bindings (Prelude.bindingList bindings "let")
+					bindings (.copy (Prelude.bindingList bindings "let"))
 					body (rest args)
 					scope (new Map<String,Dynamic>)]
 				(localScopes.push scope)
@@ -135,7 +135,6 @@
 							(cc (Reflect.callMethod null f values)))))
 				// Method/function call
 				((CallExp callable args)
-					(transformToFieldExp callable)
 					(evalCC callable ->f {
 						(_evalAllCC args ->values
 							(case callable
@@ -189,7 +188,7 @@
 							(cc f)
 							(return)))
 					// Check for field access
-					(when (transformToFieldExp exp)
+					(whenLet [exp (transformToFieldExp exp)]
 						(evalCC exp cc)
 						(return))
 					// Check for ident aliases
@@ -206,12 +205,14 @@
 					(throw "Can't interpret $(Reader.toString def)"))))
 		(otherwise (throw "Can't interpret ${input}"))))
 
-(method :Void _evalAllCC [:Array<Dynamic> inputs :Array<Dynamic>->Void cc &opt :Array<Dynamic> outputs]
-	(unless outputs (set outputs []))
+(method :Void _evalAllCC [:Array<Dynamic> inputs :Array<Dynamic>->Void cc]
+	(__evalAllCC (inputs.copy) cc []))
+
+(method :Void __evalAllCC [:Array<Dynamic> inputs :Array<Dynamic>->Void cc :Array<Dynamic> outputs]
 	(if inputs
 			(evalCC (inputs.shift) ->v {
 				(outputs.push v)
-				(_evalAllCC inputs cc outputs)
+				(__evalAllCC inputs cc outputs)
 			})
 		(cc outputs)))
 
@@ -227,7 +228,5 @@
 							(let [safe (StringTools.startsWith part "?")]
 								(when safe (set part (part.substr 1)))
 								(set newExp (makeExp (FieldExp part newExp safe)))))
-						(set exp.def newExp.def)
-						(return true)))))
-		(never otherwise))
-	false)
+						(return newExp)))))
+		(otherwise (return null))))