Phobos usability with text files

[Andrei Alexandrescu]

On 12/26/10 11:56 AM, bearophile wrote:
> Andrei:
>
>> But you don't need a new string for each line to evaluate max over
>>  line lengths; the current byLine works.<
>
> Right. There are various different ways to implement that little task
> in functional style. But the task requires to print the longest ones.
> So you have to filter according to the max length. And if you filter
> you consume the iterable (I think). So you need to dup the array
> again.
>
> It looks simple, but I have tried to create a new version like that
> writing some versions, and I have had several 'access violations'.
> This very bad for people that want to write a script with D.
>
>
>> Generally I think buffer reuse in byLine() is too valuable to let
>> go.
>
> In my post you see I have never suggested to remove buffer reuse.
>
> I have suggested two possible alternatives. In both alternatives the
>  byLine() is split into two different methods:
>
> First possibility, this is my preferred: 1a) Modify byLine() so it
> doesn't reuse the buffer. 1b) Add another method, like byFastLine()
> that reuses the buffer.
>
>
> Alternative: 2a) Keep byLine() as it is now, so it reuses the
> buffer. 2b) Add another method, like byDupLine() that doesn't reuse
> the buffer.
>
>
> In the post I have explained the rationale behind this.
>
> I prefer the first possibility because the D Zen says that the more
> safe option is the default one, and the faster less safe is on
> request (and I agree with this part of the D Zen).

Well the D Zen would attempt to reconcile the two such that the obvious 
option is the safest and the fastest.

Let's also not forget that "safe" is a bit abused here - we're not 
talking about lack of safety as much as incorrect results.

Maybe a byLine!string() would be the best of both worlds by 
automatically calling to!string against each line. That can actually be 
nicely extended to e.g. byLine!(double[]) to automatically read lines of 
whitespace-separated doubles.

> Talking about usability and egonomy in this newsgroups is sometimes a
> very tiring job :-) Even very little things seem to require a lot of
> work and discussions.

One possible issue is that you start with the assumption you're 
unequivocally right in matters that are highly debatable. That sometimes 
makes it tiring for the rest of us, too, but I'm not one to complain :o).


Andrei