OokBF Interpreter and Debugger

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OokBF Documentation

Contents

Emulator Specification

  • supports both the Ook! language and the BF language
  • 4 MiB cell array
  • each cell is a byte with values from 0 to 255
  • byte values use wrap-around (modulo arithmetic)
  • memory location pointer wrap-around is disallowed (i.e. runtime error)

Emulator Features

  • counting executed instructions, with precision of a single instruction
  • WebAssembly JIT interpreter with asynchronous execution
  • outputs to ANSI terminal or to DOS console
  • optional support for UTF-8
  • EOF settings
  • debugger with two break conditionals
  • debugger with memory watch
  • includes a language converter and auto-detector

ANSI Terminal with UTF-8

  • special character sequences VT100 / VT220 compatible, except when they are not
  • 80-column output
  • also supports 8-bit ANSI colors
  • also supports 24-bit ANSI colors
  • current emulation is by Xterm.js 5.4.0; it is imperfect
  • Line Feed (U+000A) moves to the start of a new line
  • disallowed output code points (cause a runtime error): 
                 0     NUL     Null Character
             4     EOT     End of Transmission
             5     ENQ     Enquiry
            14     SO      Shift Out
            15     SI      Shift In
            16     DLE     Data Link Escape
  • color table: 
             code   name            normal                bright
        -------------------------------------------------------------
            0   black       (  0,   0,   0)       (128, 128, 128)
            1   red         (205,  40,  40)       (255,  85,  85)
            2   green       (40 , 188,  40)       (  0, 255,   0)
            3   yellow      (188, 188,  40)       (255, 255,   0)
            4   blue        (40 ,  85, 255)       ( 85, 137, 255)
            5   magenta     (192,  40, 192)       (255,   0, 255)
            6   cyan        (40,  188, 188)       (  0, 255, 255)
            7   white       (205, 205, 205)       (255, 255, 255)
            8   normal      (205, 205, 205)       (205, 205, 205)
                background  ( 20,  20,  20)       ( 20,  20,  20)

UTF-8 Output Decoder

  • invalid UTF-8 byte sequences result in a runtime error
  • only a limited set of code points is supported (due to availability of glyphs in the font)
  • outputting an unsupported code point results in a runtime error
  • more than 1270 code points are supported; output font is Source Code Pro Semibold

DOS Console

  • emulates behavior of 80-column DOS console
  • uses code page 437 character set, a.k.a. CP437, a.k.a OEM-US
  • most output bytes get displayed as a single character
  • useful for debugging due to simplicity
  • Line Feed (10) moves to the start of a new line
  • when the caret moves past column 80, a newline is immediately automatically inserted, which is almost, but not quite, entirely unlike the ANSI terminal behavior
  • special characters: 
       value  name   width     description
----------------------------------------------------------------------------------------------
      0     NUL     1     Null Character: displayed as an empty space
      7     BEL     0     nothing (should produce a sound, but it doesn't)
      8     BS      -     Backspace: moves the caret one position to the left
      9     HT     1-8    Horizontal Tab: moves the caret to a multiple of 8
     10     LF      -     Line Feed: moves the caret to the beginning of the next row
     13     CR      -     Carriage Return: moves the caret to the beginning of the current row
    127     DEL     1     displayed as an empty square
    255      -      1     displayed as an empty space
  • character set CP437 (32 characters per row): 
                ☺☻♥♦♣♠    ♂♀ ♫☼►◄↕‼¶§▬↨↑↓→←∟↔▲▼
            !"#$%&'()*+,-./0123456789:;<=>?
           @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_
           `abcdefghijklmnopqrstuvwxyz{|}~☐
           ÇüéâäàåçêëèïîìÄÅÉæÆôöòûùÿÖÜ¢£¥₧ƒ
           áíóúñѪº¿⌐¬½¼¡«»░▒▓│┤╡╢╖╕╣║╗╝╜╛┐
           └┴┬├─┼╞╟╚╔╩╦╠═╬╧╨╤╥╙╘╒╓╫╪┘┌█▄▌▐▀
           αßΓπΣσµτΦΘΩδ∞φε∩≡±≥≤⌠⌡÷≈°∙·√ⁿ²■ 

DOS Console with UTF-8

  • same as DOS Console (see above), but supports UTF-8
  • useful for debugging UTF-8 output

Standard Input Box and Console Input

  • input is always converted to UTF-8
  • all code points are allowed
  • Standard Input Box only: EOF at end, behavior selected by input settings

Standard Output Box

  • for easy copy-pasting of the output
  • always contains Unicode characters (i.e. one character = one code point)
  • when UTF-8 output is disabled, all code points are in the range from 0 to 255

Language Converter and Language Auto-Detector

  • features the latest almost lossless language-agnostic conversion technology
  • engineered to the highest standard of quality: works on my computer

Additional Directives

  • %%dbg directive breaks into debugger if the debugger is enabled
  • %%dbg directive can optionally be followed by digits, and those digits are retained in the stripped code displayed by the debugger

Notes

  • To run Ook! and BF applications offline, use the OokBF Offline cross-platform package.