impls/bash/env.sh

   1 #
   2 # mal (Make a Lisp) environment definition
   3 #
   4
   5 if [ -z "${__mal_env_included__}" ]; then
   6 __mal_env_included=true
   7
   8 source $(dirname $0)/types.sh
   9
  10 # Any environment is a hash_map with an __outer__ key that refers to
  11 # a parent environment (or nil)
  12 ENV () {
  13     r=
  14     _hash_map
  15     local env="${r}"
  16     if [[ "${1}" ]]; then
  17         outer="${1}"; shift
  18         _assoc! "${env}" "__outer__" "${outer}"
  19     else
  20         _assoc! "${env}" "__outer__" "${__nil}"
  21     fi
  22     r="${env}"
  23
  24     if [[ "${1}" && "${@}" ]]; then
  25         local binds=(${ANON["${1}"]}); shift
  26         local idx=0
  27         while [[ "${binds["${idx}"]}" ]]; do
  28             local fp="${ANON["${binds["${idx}"]}"]}"
  29             if [[ "${fp}" == "&" ]]; then
  30                 idx=$(( idx + 1 ))
  31                 fp="${ANON["${binds["${idx}"]}"]}"
  32                 _list "${@}"
  33                 _assoc! "${env}" "${fp}" "${r}"
  34                 break
  35             else
  36                 _assoc! "${env}" "${fp}" "${1}"
  37                 shift
  38                 idx=$(( idx + 1 ))
  39             fi
  40         done
  41     fi
  42     r="${env}"
  43 }
  44
  45 # Find the environment with the key set and return the environment
  46 ENV_FIND () {
  47     if _contains? "${1}" "${ANON["${2}"]}"; then
  48         r="${1}"
  49     else
  50         local obj="${ANON["${1}"]}"
  51         eval 'local outer=${'${obj}'["__outer__"]}'
  52         if [[ "${outer}" && "${outer}" != "${__nil}" ]]; then
  53             ENV_FIND "${outer}" "${2}"
  54         else
  55             r=
  56         fi
  57     fi
  58 }
  59
  60 # Find the environment with the key set and return the value of the
  61 # key in that environment. If no environment contains the key then
  62 # return an error
  63 ENV_GET () {
  64     ENV_FIND "${1}" "${2}"
  65     local env="${r}"
  66     local key="${ANON["${2}"]}"
  67     if [[ "${r}" ]]; then
  68         local obj="${ANON["${env}"]}"
  69         eval 'r=${'${obj}'["'${key}'"]}'
  70     else
  71         _error "'${key}' not found"
  72     fi
  73 }
  74
  75 ENV_SET () {
  76     local key="${ANON["${2}"]}"
  77     _assoc! "${1}" "${key}" "${3}"
  78 }
  79
  80 fi