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Re: utf




Greg Wooledge (2018-04-04):
> Does it count if we want the 1st char, then the 2nd char, then the 3rd
> char, then the 4th char, and so on?  Or is that not blue enough?

It is not out of the blue, it is in sequence.

> How about the last char?  Or the last two chars?

Ditto.

>						    Or all chars starting
> just after the last slash or period?

There is no n here, you have to first look for the last slash.


> How about performing a checksum like the
> <https://en.wikipedia.org/wiki/Luhn_algorithm> on a user input string
> which is supposed to be a 10-digit
> <https://en.wikipedia.org/wiki/National_Provider_Identifier> ?

Again, in sequence.

> Might it be useful to check the length of an input string before
> bothering to decompose it into individual digits and perform the
> arithmetic?

And to check it is made of all digits. Checking the length is only a
byproduct.

>	       And here, by "length", I mean "number of characters".
> You can see how that might be a handy thing, right?

Still, no.

> Length as in "number of bytes required to store it" is also an
> important value, of course.

You have to compute it to store it, indeed.

> Character length is also useful when displaying strings on
> CHARACTER-ORIENTED OUTPUT MEDIA.  Like terminals.  You know, those
> things that Unix-like systems use all the time?  How else are you
> going to space-pad the fields so that the output columns line up,
> if you don't know how many extra spaces you need, because you don't
> know the length of the string?

I do not know. Please tell me, how do you handle control characters,
escape sequence, double-width characters, etc., without walking the
string in sequence?

> (It's frankly disturbing to me that when I talked about length being
> relevant when printing strings, you immediately jumped to "pixels" and
> "fonts".  This tells me that you no longer accept the terminal as your
> lord and savior.  If you ever did.)

I do not have a "lord and savior". I use the terminal a lot, but I am
aware of the hidden complexities.

> All of these things matter, and are real, and don't necessarily indicate
> "botched design".

All these things matter, but they do not require random access in a
string by char number.

Regards,

-- 
  Nicolas George

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