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mal/bash/step2_eval.sh
2017-10-11 15:58:36 -04:00

99 lines
2.3 KiB
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#!/usr/bin/env bash
source $(dirname $0)/reader.sh
source $(dirname $0)/printer.sh
# read
READ () {
[ "${1}" ] && r="${1}" || READLINE
READ_STR "${r}"
}
# eval
EVAL_AST () {
local ast="${1}" env="${2}"
#_pr_str "${ast}"; echo "EVAL_AST '${ast}:${r} / ${env}'"
_obj_type "${ast}"; local ot="${r}"
case "${ot}" in
symbol)
local val="${ANON["${ast}"]}"
eval r="\${${env}["${val}"]}"
[ "${r}" ] || _error "'${val}' not found" ;;
list)
_map_with_type _list EVAL "${ast}" "${env}" ;;
vector)
_map_with_type _vector EVAL "${ast}" "${env}" ;;
hash_map)
local res="" key= val="" hm="${ANON["${ast}"]}"
_hash_map; local new_hm="${r}"
eval local keys="\${!${hm}[@]}"
for key in ${keys}; do
eval val="\${${hm}[\"${key}\"]}"
EVAL "${val}" "${env}"
_assoc! "${new_hm}" "${key}" "${r}"
done
r="${new_hm}" ;;
*)
r="${ast}" ;;
esac
}
EVAL () {
local ast="${1}" env="${2}"
r=
[[ "${__ERROR}" ]] && return 1
#_pr_str "${ast}"; echo "EVAL '${r} / ${env}'"
_obj_type "${ast}"; local ot="${r}"
if [[ "${ot}" != "list" ]]; then
EVAL_AST "${ast}" "${env}"
return
fi
# apply list
_empty? "${ast}" && r="${ast}" && return
EVAL_AST "${ast}" "${env}"
[[ "${__ERROR}" ]] && return 1
local el="${r}"
_first "${el}"; local f="${r}"
_rest "${el}"; local args="${ANON["${r}"]}"
#echo "invoke: ${f} ${args}"
eval ${f} ${args}
}
# print
PRINT () {
if [[ "${__ERROR}" ]]; then
_pr_str "${__ERROR}" yes
r="Error: ${r}"
__ERROR=
else
_pr_str "${1}" yes
fi
}
# repl
declare -A REPL_ENV
REP () {
r=
READ "${1}"
EVAL "${r}" REPL_ENV
PRINT "${r}"
}
plus () { r=$(( ${ANON["${1}"]} + ${ANON["${2}"]} )); _number "${r}"; }
minus () { r=$(( ${ANON["${1}"]} - ${ANON["${2}"]} )); _number "${r}"; }
multiply () { r=$(( ${ANON["${1}"]} * ${ANON["${2}"]} )); _number "${r}"; }
divide () { r=$(( ${ANON["${1}"]} / ${ANON["${2}"]} )); _number "${r}"; }
REPL_ENV["+"]=plus
REPL_ENV["-"]=minus
REPL_ENV["__STAR__"]=multiply
REPL_ENV["/"]=divide
# repl loop
while true; do
READLINE "user> " || exit "$?"
[[ "${r}" ]] && REP "${r}" && echo "${r}"
done