[Info-vax] Suggestion: Adding a /SORT option to DIRECTORY and F$SEARCH ?

[Arne Vajhøj]

On 1/26/2022 8:30 AM, Arne Vajhøj wrote:
> On 1/26/2022 8:20 AM, Jan-Erik Söderholm wrote:
>> Den 2022-01-26 kl. 13:49, skrev John Wallace:
>>> On Tuesday, 25 January 2022 at 19:09:32 UTC, Simon Clubley wrote:
>>>> It would be nice to be able to see the output from a DIRECTORY command
>>>> optionally sorted by one of largest size, smallest size, oldest date,
>>>> newest date, etc.
>>>>
>>>> Likewise, it would be nice to be able to optionally specify the sort
>>>> order in which filenames are returned by f$search().
>>>>
>>>> Does anyone agree ?
> 
>>> (ignoring f$search for now)
>>>
>>> You mean like DIR on RT11 (single user PDP11 OS) has had since the 
>>> 1990s or thereabouts?
>>>
>>> .DIR /SORT:[sort_option]
>>>
>>> Sort_options include DATE and SIZE.
>>>
>>> You can also include a /REVERSE qualifier to reverse the default sort 
>>> order.
>>>
>>> See e.g. 
>>> http://www.bitsavers.org/pdf/dec/pdp11/rt11/v5.6_Aug91/AA-PDU0A-TC_RT-11_Commands_Manual_Aug91.pdf 
>>>
>>> Somebody must have thought it was worth doing.
>>
>> Might need a new message:
>>
>> %DIRECT-E-TOLARGETOSORT, directory to large for SORT qualifier
>>
>> Since the file names can not be read in any other sorting order
>> then alphabetical, they need to be read into memory and sorted.
> 
> True, but with modern HW sizes then it would be an extremely
> rare case.
> 
> 1 thousand entries of 256 bytes is only 256 KB.
> 
> 1 million entries of 256 bytes is "only" 256 MB.

There are two different approaches:
- read into a linear data structure and sort that
- read into a tree
but it should not be that different.

Arne