Re: PATCH: relpath

[Jim Meyering]

Pádraig Brady wrote:
> On 12/31/2011 11:27 AM, Jim Meyering wrote:
>> Pádraig Brady wrote:
>> ...
>>>> Reading only the documentation for --relative-base=FILE,
>>>> I am not sure how it works:
>>>>
>>>> `--relative-base=FILE'
>>>>      Ensure both the `--relative-to' and processed files are
>>>>      subdirectories of FILE, or otherwise output the absolute file name.
>>>>      Note this option honors the `-m' and `-e' options pertaining to
>>>>      file existence.
>>>>
>>>> An example or two would help a lot.
>>>
>>> I'll add something along these lines:
>>
>> Thanks.
>>
>>> $ realpath --relative-to=/usr /tmp /usr/bin
>>> ../tmp
>>
>> I see two lines of output.  I guess you missed the latter?
>>
>>     $ ./realpath --relative-to=/usr /tmp /usr/bin
>>     ../tmp
>>     bin
>>
>>> $ realpath --relative-base=/usr --relative-to=/usr /tmp /usr/bin
>>> /tmp
>>> bin
>>
>> Good.  That makes it clearer.
>> The "Ensure" threw me.  It's not really ensuring it.
>> Maybe something like this?
>>
>>    `--relative-base=BASE'
>>         When both the `--relative-to' file and a listed FILE are
>>         descendants of BASE, print a BASE-relative name for FILE.
>>         Otherwise, print FILE's absolute name.
>>         Note this option honors the `-m' and `-e' options pertaining to
>>         file existence.
>>
>> There's probably more to consider when the --relative-to= and
>> --relative-base= specified names are different, but I haven't
>> thought about that.
>
> Well it's setting a BASE, past which "../" will not be generated for.
> This does seem fairly useful and provides compatibility with `relpath -d ...`.
> I went with:
>
> `--relative-base=BASE'
>      Only output relative names when both the `--relative-to' and processed
>      FILEs are descendants of BASE.  Otherwise output the absolute file name.
>      Note this option honors the @option{-m} and @option{-e} options
>      pertaining to file existence.

Thanks.

  But that doesn't say what a printed relative name is relative to.
  Think of it as a specification.  I could not use that description
  as a basis for implementing the code.  As a naive user, I'd be hard
  pressed to predict what it will print.

  Formatting nit:
  It's not clear if what you've quoted is texinfo, but it looks like it.
  If so, you'll want @option{...} around --relative-to and to use @var{file}
  and @var{base} so that we get FILE and BASE in "info" output.

  If you retain the first two words, please reorder them:
  "Output only"

I will push the df change tomorrow and then make a pre-release snapshot,
planning to make the release late in the week or early next.