diff kitten: Add keybindings to scroll by a page

kittens/diff/config.py

@@ -73,7 +73,7 @@ def parse_scroll_by(func, rest):
 @func_with_args('scroll_to')
 def parse_scroll_to(func, rest):
     rest = rest.lower()
-    if rest not in {'start', 'end', 'next-change', 'prev-change'}:
+    if rest not in {'start', 'end', 'next-change', 'prev-change', 'next-page', 'prev-page'}:
         rest = 'start'
     return func, rest
 

kittens/diff/diff.conf

@@ -47,6 +47,9 @@ map down scroll_by 1
 map up scroll_by -1
 map home scroll_to start
 map end scroll_to end
+map page_down scroll_to next-page
+map page_up scroll_to prev-page
+map space scroll_to next-page
 map n scroll_to next-change
 map p scroll_to prev-change
 map a change_context all

kittens/diff/main.py

@@ -76,7 +76,10 @@ class DiffHandler(Handler):
                 where = args[0]
                 if 'change' in where:
                     return self.scroll_to_next_change(backwards='prev' in where)
-                amt = len(self.diff_lines) * (1 if 'end' in where else -1)
+                if 'page' in where:
+                    amt = self.num_lines * (1 if 'next' in where else -1)
+                else:
+                    amt = len(self.diff_lines) * (1 if 'end' in where else -1)
                 return self.scroll_lines(amt)
             if func == 'change_context':
                 new_ctx = self.current_context_count