New macro stepper option: show one term per step rather than term->term

svn: r5308

original commit: c5b19a52a94099c8ee0429d8d514218673035fa1

collects/macro-debugger/view/cursor.ss

@@ -46,10 +46,18 @@
     (make-cursor null items))
 
   (define (cursor:current c)
+    (cursor:next c))
+
+  (define (cursor:next c)
     (let ([suffix (cursor-suffix c)])
       (if (pair? suffix)
           (car suffix)
           #f)))
+  (define (cursor:prev c)
+    (let ([prefix (cursor-prefix c)])
+      (if (pair? prefix)
+          (car prefix)
+          #f)))
 
   (define (cursor:move-to-start c)
     (when (cursor:can-move-previous? c)
@@ -83,4 +91,4 @@
   
   
   
-  )
+  )

collects/macro-debugger/view/interfaces.ss

@@ -28,6 +28,7 @@
      pref:show-rename-steps?
      pref:highlight-foci?
      pref:suppress-warnings?
+     pref:one-by-one?
      ))
 
   ;; macro-stepper-config%

collects/macro-debugger/view/prefs.ss

@@ -30,6 +30,7 @@
       (preferences:set-default 'MacroStepper:HighlightFoci? #t boolean?)
       (preferences:set-default 'MacroStepper:ShowRenameSteps? #f boolean?)
       (preferences:set-default 'MacroStepper:SuppressWarnings? #f boolean?)
+      (preferences:set-default 'MacroStepper:OneByOne? #f boolean?)
       
       (pref:get/set pref:width MacroStepper:Frame:Width)
       (pref:get/set pref:height MacroStepper:Frame:Height)
@@ -43,6 +44,7 @@
       (pref:get/set pref:highlight-foci? MacroStepper:HighlightFoci?)
       (pref:get/set pref:show-rename-steps? MacroStepper:ShowRenameSteps?)
       (pref:get/set pref:suppress-warnings? MacroStepper:SuppressWarnings?)
+      (pref:get/set pref:one-by-one? MacroStepper:OneByOne?)
       
       ))
   )