[include-fixer] give users an option to show N more headers in case there are too many candidates.

[ioeric]

Summary

give users an option to show N more headers in case there are too many candidates.

[bkramer]

I'm not convinced that this use case is common enough to make the interface more complex. Should we remove (a) in favor of this?

[ioeric]

• remove option (a) in favor of option (m); show a new prompt on invalid option instead of aborting.

include-fixer/tool/clang-include-fixer.py

if vim.eval('exists("g:clang_include_fixer_path")') == "1":
   binary = vim.eval('g:clang_include_fixer_path')
 
 maximum_suggested_headers=3
 if vim.eval('exists("g:clang_include_fixer_maximum_suggested_headers")') == "1":
   maximum_suggested_headers = max(
       1,
       vim.eval('g:clang_include_fixer_maximum_suggested_headers'))
 
+increment_num=5
+if vim.eval('exists("g:clang_include_fixer_increment_num")') == "1":
+  increment_num = max(
+      1,
+      vim.eval('g:clang_include_fixer_increment_num'))
 
 def GetUserSelection(message, headers, maximum_suggested_headers):
   eval_message = message + '\n'
   for idx, header in enumerate(headers[0:maximum_suggested_headers]):
     eval_message += "({0}). {1}\n".format(idx+1, header)
   eval_message += "Enter (q) to quit;"
   if maximum_suggested_headers < len(headers):
-    eval_message += " (a) to show all candidates.";
+    eval_message += " (m) to show {0} more candidates.".format(
+        min(increment_num, len(headers) - maximum_suggested_headers))
+
   eval_message += "\nSelect (default 1): "
   res = vim.eval("input('{0}')".format(eval_message))
   if res == '':
     # choose the top ranked header by default
     idx = 1
   elif res == 'q':
     raise Exception('   Insertion cancelled...')
-  elif res == 'a' and maximum_suggested_headers < len(headers):
-    return GetUserSelection(message, headers, len(headers))
+  elif res == 'm':
+    return GetUserSelection(message,
+                            headers, maximum_suggested_headers + increment_num)
   else:
     try:
       idx = int(res)
       if idx <= 0 or idx > len(headers):
         raise Exception()
     except Exception:
-        raise Exception('   ERROR: Invalid option "{0}"...Abort!'.format(res))
+      # Show a new prompt on invalid option instead of aborting so that users
+      # don't need to wait for another include-fixer run.
+      print >> sys.stderr, "Invalid option:", res
+      return GetUserSelection(message, headers, maximum_suggested_headers)
   return headers[idx-1]
 
 def execute(command, text):
   p = subprocess.Popen(command,
                        stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                        stdin=subprocess.PIPE)
   return p.communicate(input=text)