How to print unicode characters (no library)?
maxhaton at gmail.com
Sun Dec 26 23:45:25 UTC 2021
On Sunday, 26 December 2021 at 21:22:42 UTC, Adam Ruppe wrote:
> On Sunday, 26 December 2021 at 20:50:39 UTC, rempas wrote:
> write just transfers a sequence of bytes. It doesn't know nor
> care what they represent - that's for the receiving end to
> figure out.
> You are mistaken. There's several exceptions, utf-16 can come
> in pairs, and even utf-32 has multiple "characters" that
> combine onto one thing on screen.
> I prefer to think of a string as a little virtual machine that
> can be run to produce output rather than actually being
> "characters". Even with plain ascii, consider the backspace
> "character" - it is more an instruction to go back than it is a
> thing that is displayed on its own.
> This is because the *receiving program* treats them as utf-8
> and runs it accordingly. Not all terminals will necessarily do
> this, and programs you pipe to can do it very differently.
> The [w|d|]string.length function returns the number of elements
> in there, which is bytes for string, 16 bit elements for
> wstring (so bytes / 2), or 32 bit elements for dstring (so
> bytes / 4).
> This is not necessarily related to the number of characters
> yes, it just passes bytes through. It doesn't know they are
> supposed to be characters...
I think that mental model is pretty good actually. Maybe a more
specific idea exists, but this virtual machine concept does
actually explain to the new programmer to expect dragons - or at
least that the days of plain ASCII are long gone (and never
happened, e.g. backspace as you say)
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