OpenEuphoria

Re: walk_dir issue

• Posted by "Juergen Luethje" <j.lue at gmx.de> Nov 25, 2004
• 590 views

Robert Craig wrote:

> Juergen Luethje wrote:

<snip>

>> It depends on what you actually want walk_dir() to do.
>>
>> a) According to the current documentation, the first parameter should be
>>    a path name. At least on DOS and Windows, something that contains a
>>    wildcard is not a valid path name.
>>    Yes, if the first parameter actually is supposed to be a path name,
>>    then I would expect that the user-defined routine would not be called
>>    at all because no such directory as "C:\\*.txt" exists, and that
>>    walk_dir() spits out an error message.
>>
>> b) On the other hand, if it is intended that the first parameter of
>>    walk_dir() may contain wildcards, then the documentation should be
>>    changed accordingly. And the walk_dir() function must be changed, so
>>    that -- regarding my previous example -- onyly "C:" is given to the
>>    user-defined function as the path name, rather than "C:\\*.txt",
>>    because "C:\\*.txt" is not a path name.
>
> I definitely intended and documented it as (a).
>
> The fact that walk_dir doesn't immediately crash and burn
> when given wildcards, is just a fluke, based on the
> fact that dir() accepts wildcards, which is also a fluke
> (now documented). I didn't even know myself that
> Euphoria's dir() worked with wildcards, until a user
> pointed it out to me. By the way, dir() does
> not work with wildcards on Linux/FreeBSD.
>
> To keep everyone happy, I'll add "the directory path must not
> contain wildcards" to the docs. Sort of like "This machine
> converts oranges into orange juice. Do not insert watermelons".  


The main issue is not in the docs, but in the walk_dir() function itself.
Here is the beginning (2.5 alpha -- I left out some comments):

global function walk_dir(sequence path_name, integer your_function,
                         integer scan_subdirs)
   object d, abort_now

   -- get the full directory information
   if my_dir = DEFAULT then
      d = default_dir(path_name)
   else
      d = call_func(my_dir, {path_name})
   end if
   if atom(d) then
      return W_BAD_PATH
   end if

Why not add something like:

if platform() != LINUX and
   (find('*', path_name) or find('?', path_name)) then
      return W_BAD_PATH
   end if

Relying on the assumption that only proper arguments are passed to
functions is, say "very optimistic". 
That's the reason why we also often use (built-in or user-defined) types
for parameter checking, no?

Regards,
   Juergen

-- 
Have you read a good program lately?