Re: extended characterset output

[Ali Çehreli via Digitalmars-d-learn]

On 4/7/22 23:13, anonymous wrote:
> What's the proper way to output all characters in the extended character
> set?
It is not easy to answer because there are a number of concepts here 
that may make it trivial or complicated.

The configuration of the output device matters. Is it set to 
Windows-1252 or are you using Unicode strings in Python?

>
> ```d
> void main()
> {
>      foreach(char c; 0 .. 256)

'char' is wrong there because 'char' has a very special meaning in D: A 
UTF-8 code unit. Not a full Unicode character in many cases, especially 
in the "extended" set.

I think your problem will be solved simply by replacing 'char' with 
'dchar' there:

  foreach (dchar c; ...

However, isControl() below won't work because isControl() only knows 
about the ASCII table. It would miss the unprintable characters above 127.

>      {
>         write(isControl(c) ? '.' : c);
>      }
> }
> ```

This works:

import std.stdio;

bool isPrintableLatin1(dchar value) {
  if (value < 32) {
    return false;
  }

  if (value > 126 && value < 161) {
    return false;
  }

  return true;
}

void main() {
  foreach (dchar c; 0 .. 256) {
    write(isPrintableLatin1(c) ? c : '.');
  }

  writeln();

  // import std.encoding;

  // foreach(ubyte c; 0 .. 256) {
  //   if (isPrintableLatin1(c)) {
  //     Latin1Char[1] from = [ cast(Latin1Char)c ];
  //     string to;
  //     transcode(from, to);
  //     write(to);

  //   } else {
  //     write('.');
  //   }
  // }

  // writeln();
}

I left some code commented-out, which I experimented with. (That works 
as well.)

Ali