asmr-lisp.sh

cons () {
  eval CAR"$CNUM"="$1"; eval CDR"$CNUM"="$2";
  CONSR="$CNUM.conscell"; CNUM="$((CNUM+1))";
}
car () { eval CARR="\$CAR${1%%.conscell}"; }
cdr () { eval CDRR="\$CDR${1%%.conscell}"; }

TRUE=1; FALSE=0; NULL="empty";
pairp () {
  case "$1" in (*.conscell) PAIRPR="$TRUE" ;; (*)
  PAIRPR="$FALSE" ;; esac
}
eq () {
  pairp "$1"; case "$PAIRPR" in ("$TRUE") EQR="$FALSE" ;; (*)
  pairp "$2"; case "$PAIRPR" in ("$TRUE") EQR="$FALSE" ;; (*)
  case "$1" in ("$2") EQR="$TRUE" ;; (*)
  EQR="$FALSE" ;; esac ;; esac ;; esac
}
intp () {
  case "${1#[+-]}" in (''|*[!0-9]*) INTPR="$FALSE" ;; (*)
  INTPR="$TRUE" ;; esac
}

ls () {
  car "$1"; sw "$CARR"; cdr "$1"; local d="$CDRR";
  case "$d" in ("$NULL") printf "" ;; (*)
  printf " "; ls "$d" ;; esac
}
sw () {
  pairp "$1"; case "$PAIRPR" in ("$TRUE") printf "("; ls "$1"; printf ")" ;; (*)
  intp "$1"; case "$INTPR" in ("$TRUE") printf "%d" "$1" ;; (*)
  printf "$1" ;; esac ;; esac
}
sr_lex () {
  local s; read s;
  s=`echo $s | sed -r "s/[ ]+/ /g" | sed -e "s/)/ ) /g" | sed -e "s/(/ ( /g"`;
  for t in `echo "$s"`; do eval TOKEN"$TNUM"="\$t"; TNUM="$((TNUM+1))"; done;
}
sr_syn0 () {
  local t; eval t="\$TOKEN$SPOS";
  case "$t" in ("(") SPOS="$((SPOS-1))"; SRSYN0R="$1" ;; (*)
  sr_syn; cons "$SRSYNR" "$1"; sr_syn0 "$CONSR" ;; esac
}
sr_syn () {
  local t; eval t="\$TOKEN$SPOS"; SPOS="$((SPOS-1))";
  case "$t" in (")") sr_syn0 "$NULL"; SRSYNR="$SRSYN0R" ;; (*)
  SRSYNR="$t" ;; esac
}

ap () {
  eq "$1" "$NULL"; case "$EQR" in ("$TRUE") APR="$2" ;; (*)
  cdr "$1"; ap "$CDRR" "$2"; car "$1"; cons "$CARR" "$APR"; APR="$CONSR" ;; esac
}
pm () {
  eq "$1" "$NULL"; case "$EQR" in ("$TRUE") PMR="$NULL" ;; (*)
  eq "$2" "$NULL"; case "$EQR" in ("$TRUE") PMR="$NULL" ;; (*)
  cdr "$1"; local d1="$CDRR"; cdr "$2"; local d2="$CDRR"; pm "$d1" "$d2";
  car "$2"; cons "$CARR" "$PMR"; car "$1"; cons "$CARR" "$CONSR";
  PMR="$CONSR" ;; esac ;; esac
}
pq () {
  eq "$2" "$NULL"; case "$EQR" in ("$TRUE") PQR="$FALSE" ;; (*)
  car "$2"; local a="$CARR"; cdr "$2"; local d="$CDRR";
  eq "$1" "$a"; case "$EQR" in ("$TRUE") car "$d"; PQR="$CARR" ;; (*)
  cdr "$d"; d="$CDRR"; pq "$1" "$d" ;; esac ;; esac
}
sq () {
  case "$1" in ("+"|"-"|"eq?"|"cons"|"car"|"cdr") SQR="$1" ;; (*)
  pq "$1" "$2"; SQR="$PQR" ;; esac
}

ay () {
  car "$2"; local a1="$CARR";
  case "$1" in ("+"|"-"|"cons"|"eq?")
    cdr "$2"; local a2="$CDRR"; car "$a2"; a2="$CARR";
    case "$1" in ("eq?") eq "$a1" "$a2"; AYR="$EQR"
    ;; ("cons") cons "$a1" "$a2"; AYR="$CONSR"
    ;; (*) AYR="$(($a1$1$a2))" ;; esac
  ;; ("car") car "$a1"; AYR="$CARR"
  ;; ("cdr") cdr "$a1"; AYR="$CDRR" ;; esac
}

evpush () { eval STACK"$SNUM"="$EVR"; SNUM="$((SNUM+1))"; }
evpop  () { SNUM="$((SNUM-1))"; eval EVR="\$STACK$SNUM"; }
ea () {
  eq "$1" "$NULL"; case "$EQR" in ("$TRUE") EAR="$NULL" ;; (*)
  car "$1"; ev "$CARR" "$2"; evpush; cdr "$1"; ea "$CDRR" "$2"; evpop;
  cons "$EVR" "$EAR"; EAR="$CONSR" ;; esac
}

ev () {
  pairp "$1";
  case "$PAIRPR" in ("$TRUE")
    car "$1"; local s0="$CARR"; cdr "$1"; local sr="$CDRR";
    case "$s0" in ("quote") car "$sr"; EVR="$CARR"
    ;; ("if")
      car "$sr"; local s1="$CARR"; cdr "$sr"; local sr1="$CDRR"; ev "$s1" "$2"
      case "$EVR" in ("$TRUE") car "$sr1"; ev "$CARR" "$2" ;; (*)
      cdr "$sr1"; local sr2="$CDRR"; car "$sr2"; ev "$CARR" "$2" ;; esac
    ;; ("lambda") cons "$2" "$NULL"; ap "$1" "$CONSR"; EVR="$APR";
    ;; (*)
      ev "$s0" "$2"; local f="$EVR"; ea "$sr" "$2"; local a="$EAR"; pairp "$f";
      case "$PAIRPR" in ("$FALSE") ay "$f" "$a"; EVR="$AYR" ;; (*)
      cdr "$f";   local fr1="$CDRR"; car "$fr1"; local f1="$CARR";
      cdr "$fr1"; local fr2="$CDRR"; car "$fr2"; local f2="$CARR";
      cdr "$fr2"; local fr3="$CDRR"; car "$fr3"; local f3="$CARR";
      pm "$f1" "$a"; ap "$PMR" "$f3"; ev "$f2" "$APR" ;; esac ;; esac
  ;; (*)
  intp "$1"; case "$INTPR" in ("$TRUE") EVR="$1" ;; (*)
  sq "$1" "$2"; EVR="$SQR" ;; esac ;; esac
}

TNUM=0; sr_lex;
SPOS="$((TNUM-1))"; sr_syn;
SNUM=0; ev "$SRSYNR" "$NULL"; sw "$EVR";