bash/step3_env.sh

   1 #!/usr/bin/env bash
   2
   3 source $(dirname $0)/reader.sh
   4 source $(dirname $0)/printer.sh
   5 source $(dirname $0)/env.sh
   6
   7 # read
   8 READ () {
   9     [ "${1}" ] && r="${1}" || READLINE
  10     READ_STR "${r}"
  11 }
  12
  13 # eval
  14 EVAL_AST () {
  15     local ast="${1}" env="${2}"
  16     #_pr_str "${ast}"; echo "EVAL_AST '${ast}:${r} / ${env}'"
  17     _obj_type "${ast}"; local ot="${r}"
  18     case "${ot}" in
  19     symbol)
  20         ENV_GET "${env}" "${ast}"
  21         return ;;
  22     list)
  23         _map_with_type _list EVAL "${ast}" "${env}" ;;
  24     vector)
  25         _map_with_type _vector EVAL "${ast}" "${env}" ;;
  26     hash_map)
  27         local res="" key= val="" hm="${ANON["${ast}"]}"
  28         _hash_map; local new_hm="${r}"
  29         eval local keys="\${!${hm}[@]}"
  30         for key in ${keys}; do
  31             eval val="\${${hm}[\"${key}\"]}"
  32             EVAL "${val}" "${env}"
  33             _assoc! "${new_hm}" "${key}" "${r}"
  34         done
  35         r="${new_hm}" ;;
  36     *)
  37         r="${ast}" ;;
  38     esac
  39 }
  40
  41 EVAL () {
  42     local ast="${1}" env="${2}"
  43     r=
  44     [[ "${__ERROR}" ]] && return 1
  45     #_pr_str "${ast}"; echo "EVAL '${r} / ${env}'"
  46     _obj_type "${ast}"; local ot="${r}"
  47     if [[ "${ot}" != "list" ]]; then
  48         EVAL_AST "${ast}" "${env}"
  49         return
  50     fi
  51
  52     # apply list
  53     _nth "${ast}" 0; local a0="${r}"
  54     _nth "${ast}" 1; local a1="${r}"
  55     _nth "${ast}" 2; local a2="${r}"
  56     case "${ANON["${a0}"]}" in
  57         def!) EVAL "${a2}" "${env}"
  58               [[ "${__ERROR}" ]] && return 1
  59               ENV_SET "${env}" "${a1}" "${r}"
  60               return ;;
  61         let*) ENV "${env}"; local let_env="${r}"
  62               local let_pairs=(${ANON["${a1}"]})
  63               local idx=0
  64               #echo "let: [${let_pairs[*]}] for ${a2}"
  65               while [[ "${let_pairs["${idx}"]}" ]]; do
  66                   EVAL "${let_pairs[$(( idx + 1))]}" "${let_env}"
  67                   ENV_SET "${let_env}" "${let_pairs[${idx}]}" "${r}"
  68                   idx=$(( idx + 2))
  69               done
  70               EVAL "${a2}" "${let_env}"
  71               return ;;
  72         *)    EVAL_AST "${ast}" "${env}"
  73               [[ "${__ERROR}" ]] && r= && return 1
  74               local el="${r}"
  75               _first "${el}"; local f="${r}"
  76               _rest "${el}"; local args="${ANON["${r}"]}"
  77               #echo "invoke: ${f} ${args}"
  78               eval ${f} ${args}
  79               return ;;
  80     esac
  81 }
  82
  83 # print
  84 PRINT () {
  85     if [[ "${__ERROR}" ]]; then
  86         _pr_str "${__ERROR}" yes
  87         r="Error: ${r}"
  88         __ERROR=
  89     else
  90         _pr_str "${1}" yes
  91     fi
  92 }
  93
  94 # repl
  95 ENV; REPL_ENV="${r}"
  96 REP () {
  97     r=
  98     READ "${1}"
  99     EVAL "${r}" "${REPL_ENV}"
 100     PRINT "${r}"
 101 }
 102
 103 plus     () { r=$(( ${ANON["${1}"]} + ${ANON["${2}"]} )); _number "${r}"; }
 104 minus    () { r=$(( ${ANON["${1}"]} - ${ANON["${2}"]} )); _number "${r}"; }
 105 multiply () { r=$(( ${ANON["${1}"]} * ${ANON["${2}"]} )); _number "${r}"; }
 106 divide   () { r=$(( ${ANON["${1}"]} / ${ANON["${2}"]} )); _number "${r}"; }
 107
 108 _symbol "+";        ENV_SET "${REPL_ENV}" "${r}" plus
 109 _symbol "-";        ENV_SET "${REPL_ENV}" "${r}" minus
 110 _symbol "__STAR__"; ENV_SET "${REPL_ENV}" "${r}" multiply
 111 _symbol "/";        ENV_SET "${REPL_ENV}" "${r}" divide
 112
 113 # repl loop
 114 while true; do
 115     READLINE "user> " || exit "$?"
 116     [[ "${r}" ]] && REP "${r}" && echo "${r}"
 117 done