Current state of mal for Clojure West lighting talk.

1 files changed, 92 insertions, 0 deletions

diff --git a/bash/step2_eval.sh b/bash/step2_eval.sh
new file mode 100755
index 0000000..4d571e4
--- /dev/null
+++ b/bash/step2_eval.sh
@@ -0,0 +1,92 @@
+#!/bin/bash
+
+INTERACTIVE=${INTERACTIVE-yes}
+
+source $(dirname $0)/reader.sh
+
+# READ: read and parse input
+READ () {
+    READLINE
+    READ_STR "${r}"
+}
+
+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="" 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: evaluate the parameter
+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
+    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: read, eval, print, loop
+declare -A REPL_ENV
+REP () {
+    READ_STR "${1}"
+    EVAL "${r}" REPL_ENV
+    PRINT "${r}"
+}
+
+REPL_ENV["+"]=num_plus
+REPL_ENV["-"]=num_minus
+REPL_ENV["__STAR__"]=num_multiply
+REPL_ENV["/"]=num_divide
+
+if [[ -n "${INTERACTIVE}" ]]; then
+    while true; do
+        READLINE "user> " || exit "$?"
+        [[ "${r}" ]] && REP "${r}" && echo "${r}"
+    done
+fi