I’m sure lots of people will think this, so I’ll say it—

Box-drawing characters (U+2500–U+257F) are not ASCII (U+0000–U+007F).

There, got it out of my system. :-)

(I know, “ASCII art” colloquially means more than just the ASCII range.)

They sort of are.

I think the confusion arises because the IBM PC ASCII (code page 437) included comprehensive box-drawing characters between hexidecimal character positions B3 and DA. These weren't adopted into Unicode in the same character positions, but the box-drawing characters were definitely part of the commonly understood ASCII character set.

But I think that this ASCII tree editor should have a toggle option for basic vs extended ASCII, by utilising +, -, and | characters.

Indeed! I was disinclined to even look at this project because it said ASCII when the box-drawing characters are obviously a lot more suitable. It should say “text-only” or “plain-text” or similar instead.

> (I know, “ASCII art” colloquially means more than just the ASCII range.)

I recall "ASCII art" always referring to art made with the 7-bit character set, and art made with the extended CP437 characters (and including color, etc.) always being called "ANSI art".

My understanding of ASCII was influenced by tools like ASCIIDraw and ASCIIFlow, which I used them like almost 10 years ago. Inside my mind there's a voice with the same opinion of yours, but I still quite used to call plain-text drawings as "ASCII". LOL