bash/step5_tco.sh

   1 #!/usr/bin/env bash
   2
   3 source $(dirname $0)/reader.sh
   4 source $(dirname $0)/printer.sh
   5 source $(dirname $0)/env.sh
   6 source $(dirname $0)/core.sh
   7
   8 # read
   9 READ () {
  10     [ "${1}" ] && r="${1}" || READLINE
  11     READ_STR "${r}"
  12 }
  13
  14 # eval
  15 EVAL_AST () {
  16     local ast="${1}" env="${2}"
  17     #_pr_str "${ast}"; echo "EVAL_AST '${ast}:${r} / ${env}'"
  18     _obj_type "${ast}"; local ot="${r}"
  19     case "${ot}" in
  20     symbol)
  21         ENV_GET "${env}" "${ast}"
  22         return ;;
  23     list)
  24         _map_with_type _list EVAL "${ast}" "${env}" ;;
  25     vector)
  26         _map_with_type _vector EVAL "${ast}" "${env}" ;;
  27     hash_map)
  28         local res="" key= val="" hm="${ANON["${ast}"]}"
  29         _hash_map; local new_hm="${r}"
  30         eval local keys="\${!${hm}[@]}"
  31         for key in ${keys}; do
  32             eval val="\${${hm}[\"${key}\"]}"
  33             EVAL "${val}" "${env}"
  34             _assoc! "${new_hm}" "${key}" "${r}"
  35         done
  36         r="${new_hm}" ;;
  37     *)
  38         r="${ast}" ;;
  39     esac
  40 }
  41
  42 EVAL () {
  43     local ast="${1}" env="${2}"
  44     while true; do
  45     r=
  46     [[ "${__ERROR}" ]] && return 1
  47     #_pr_str "${ast}"; echo "EVAL '${r} / ${env}'"
  48     _obj_type "${ast}"; local ot="${r}"
  49     if [[ "${ot}" != "list" ]]; then
  50         EVAL_AST "${ast}" "${env}"
  51         return
  52     fi
  53
  54     # apply list
  55     _nth "${ast}" 0; local a0="${r}"
  56     _nth "${ast}" 1; local a1="${r}"
  57     _nth "${ast}" 2; local a2="${r}"
  58     case "${ANON["${a0}"]}" in
  59         def!) EVAL "${a2}" "${env}"
  60               [[ "${__ERROR}" ]] && return 1
  61               ENV_SET "${env}" "${a1}" "${r}"
  62               return ;;
  63         let*) ENV "${env}"; local let_env="${r}"
  64               local let_pairs=(${ANON["${a1}"]})
  65               local idx=0
  66               #echo "let: [${let_pairs[*]}] for ${a2}"
  67               while [[ "${let_pairs["${idx}"]}" ]]; do
  68                   EVAL "${let_pairs[$(( idx + 1))]}" "${let_env}"
  69                   ENV_SET "${let_env}" "${let_pairs[${idx}]}" "${r}"
  70                   idx=$(( idx + 2))
  71               done
  72               ast="${a2}"
  73               env="${let_env}"
  74               # Continue loop
  75               ;;
  76         do)   _count "${ast}"
  77               _slice "${ast}" 1 $(( ${r} - 2 ))
  78               EVAL_AST "${r}" "${env}"
  79               [[ "${__ERROR}" ]] && r= && return 1
  80               _last "${ast}"
  81               ast="${r}"
  82               # Continue loop
  83               ;;
  84         if)   EVAL "${a1}" "${env}"
  85               [[ "${__ERROR}" ]] && return 1
  86               if [[ "${r}" == "${__false}" || "${r}" == "${__nil}" ]]; then
  87                   # eval false form
  88                   _nth "${ast}" 3; local a3="${r}"
  89                   if [[ "${a3}" ]]; then
  90                       ast="${a3}"
  91                   else
  92                       r="${__nil}"
  93                       return
  94                   fi
  95               else
  96                   # eval true condition
  97                   ast="${a2}"
  98               fi
  99               # Continue loop
 100               ;;
 101         fn*)  _function "ENV \"${env}\" \"${a1}\" \"\${@}\"; \
 102                          EVAL \"${a2}\" \"\${r}\"" \
 103                         "${a2}" "${env}" "${a1}"
 104               return ;;
 105         *)    EVAL_AST "${ast}" "${env}"
 106               [[ "${__ERROR}" ]] && r= && return 1
 107               local el="${r}"
 108               _first "${el}"; local f="${ANON["${r}"]}"
 109               _rest "${el}"; local args="${ANON["${r}"]}"
 110               #echo "invoke: [${f}] ${args}"
 111               if [[ "${f//@/ }" != "${f}" ]]; then
 112                   set -- ${f//@/ }
 113                   ast="${2}"
 114                   ENV "${3}" "${4}" ${args}
 115                   env="${r}"
 116               else
 117                   eval ${f%%@*} ${args}
 118                   return
 119               fi
 120               # Continue loop
 121               ;;
 122     esac
 123     done
 124 }
 125
 126 # print
 127 PRINT () {
 128     if [[ "${__ERROR}" ]]; then
 129         _pr_str "${__ERROR}" yes
 130         r="Error: ${r}"
 131         __ERROR=
 132     else
 133         _pr_str "${1}" yes
 134     fi
 135 }
 136
 137 # repl
 138 ENV; REPL_ENV="${r}"
 139 REP () {
 140     r=
 141     READ "${1}"
 142     EVAL "${r}" "${REPL_ENV}"
 143     PRINT "${r}"
 144 }
 145
 146 # core.sh: defined using bash
 147 _fref () {
 148     _symbol "${1}"; local sym="${r}"
 149     _function "${2} \"\${@}\""
 150     ENV_SET "${REPL_ENV}" "${sym}" "${r}"
 151 }
 152 for n in "${!core_ns[@]}"; do _fref "${n}" "${core_ns["${n}"]}"; done
 153
 154 # core.mal: defined using the language itself
 155 REP "(def! not (fn* (a) (if a false true)))"
 156
 157 # repl loop
 158 while true; do
 159     READLINE "user> " || exit "$?"
 160     [[ "${r}" ]] && REP "${r}" && echo "${r}"
 161 done