Macrodown: BCT language interpreter

bct.mcrd

\macro \cons @hd @tl {%
  \ifempty{@tl;}{@hd;}{\ifempty{@hd;}{@tl;}{@hd;|@tl;}}}%
\macro \same @x @y {%
  \ifsame{@x;}{@y;}{*}{}}%
\macro \cat-list @lst {%
  \pop @hd @tl {@lst;}{%
    @hd;\ifempty{@tl;}{}{\cat-list{@tl;}}}}%
\macro \countdown @tmr {%
  \pop @hd @tl {@tmr;}{%
    \ifsame{@hd;}{*}{*}{@tl;}}}%
%\macro \dump-timer @tmr {%
%  \pop @hd @tl {@tmr;}{%
%    \ifsame{@hd;}{*}{*}{.\dump-timer{@tl;}}}}%
%\macro \bct-dump @stt @prg @dat @tmr @phd @dhd {%
%  DUMP\{@stt;\}\{\cat-list{@prg;}\}\{\cat-list{@dat;}\}%
%  \{\dump-timer{@tmr;}\}\{@phd;\}\{@dhd;\}}%
\macro \bct-loop @stt @prg @dat @tmr @phd @dhd {%
  %\bct-dump{@stt;}{@prg;}{@dat;}{@tmr;}{@phd;}{@dhd;}
  \pop@if@is{\same{@stt;}{A}}{%
    \pop@if@is{@dat;}{%
      \pop@if@is{@tmr;}{%
        \bct-loop{B}{@prg;}{@dat;}{\countdown{@tmr;}}{}{}}}}%
  \pop@if@is{\same{@stt;}{B}}{%
    \pop @phd1 @ptl1 {@prg;}{%
      \pop @dhd1 @dtl1 {@dat;}{%
        \bct-loop{C}{\cons{@ptl1;}{@phd1;}}{@dtl1;}{@tmr;}{@phd1;}{@dhd1;}}}}%
  \pop@if@is{\same{@stt;}{C}}{%
    \pop@if@is{\same{@phd;}{0}}{%
      \bct-loop{E}{@prg;}{@dat;}{@tmr;}{}{}}%
    \pop@if@is{\same{@phd;}{1}}{%
      \pop @phd1 @ptl1 {@prg;}{%
        \bct-loop{D}{\cons{@ptl1;}{@phd1;}}{\cons{@dhd;}{@dat;}}%
            {@tmr;}{@phd1;}{@dhd;}}}}%
  \pop@if@is{\same{@stt;}{D}}{%
    \bct-loop{E}{@prg;}%
        {\ifsame{@dhd;}{1}{@dat;|@phd;}{@dat;}}{@tmr;}{}{}}%
  \pop@if@is{\same{@stt;}{E}}{%
    \cat-list{@dat;}
    \bct-loop{A}{@prg;}{@dat;}{@tmr;}{}{}}}%
\macro \bct @prg @dat @tmr {%
  \bct-loop{A}{@prg;}{@dat;}%
      {\ifempty{@prg;}{}{\ifempty{@tmr;}{*}{@tmr;}}}{}{}}%
%-------------------------------------------------
% Run BCT with program=00111, data=101, up to 12 steps
\bct{0|0|1|1|1}{1|0|1}{||||||||||||}%
% Run BCT with program=0, data=11, until halt
%\bct{0}{1|1}{}%

BCT (Bitwise Cyclic Tag) is a Turing-complete programming language.
cf. https://esolangs.org/wiki/Bitwise_Cyclic_Tag