Mirror of forum.nim-lang.org

4777 :: Printing Unicode characters (Runes) and UTF8 Strings

• indiocolifa (orginal) [2019-04-10T17:50:23+02:00] view original

  Hi guys.

  I'm trying to use the box-drawing characters of Unicode to draw some fancy dialogs at the terminal. I could do it without problems but I'm trying to find if there is a more "straightforward" form.

  The codepoints are defined as:

  
  type
      DialogBorderRunes = enum
          dbrHLine = 0x2500
          dbrVLine = 0x2502
          dbrTopLeft = 0x250C
          dbrTopRight =0x2510
          dbrBottomLeft = 0x2514
          dbrBottomRight = 0x2518
  Run

  I can "draw"the top of the dialog with styledWrite in this manner:

  
      setCursorPos(left, top)
      stdout.styledWrite(bg, Rune(dbrTopLeft).toUTF8() &
          Rune(dbrHLine).toUTF8().repeat(dlgWidth-2) &
          Rune(dbrTopRight).toUTF8())
  Run

  All works ok, but how about the efficiency in instancing Rune and converting to UTF8 repeatedly?

  Considering that Nim string is UTF8, I'm wondering if I can do something like:

  
     stdout.styledWrite(bg, "\x250C") & "\x2500".repeat(dlgWidth-2) & "\x2510)
  Run

  I mean embedding the character codepoint in the string itself instead of creating a Rune a converting it to UTF8 subsequently?

  Thank you very much.

---

• zolern (orginal) [2019-04-11T09:31:15+02:00] view original

  You can, but string literal for unicode is "uHHHH" (exactly four hex digits), not "xHHHH"

---

• indiocolifa (orginal) [2019-04-11T19:54:59+02:00] view original

  Thanks, works awesome in Linux.

  Windows CMD.EXE shows bad characters unless I set CHCP to 65001 (UTF8).

---

• zolern (orginal) [2019-04-12T09:29:03+02:00] view original

  Yes, Windows console is set by default to regional (non unicode) code page. Anyway it is good practice if you change codepage then restore it on exit, you never know what legacy (but very very important to somebody) software depends on it :)

---