All: split types into types, env, printer, core.

- types: low-level mapping to the implementation language.
- core: functions on types that are exposed directly to mal.
- printer: implementation called by pr-str, str, prn, println.
- env: the environment implementation

- Also, unindent all TCO while loops so that the diff of step4 and
  step5 are minimized.

1 files changed, 78 insertions, 0 deletions

diff --git a/bash/env.sh b/bash/env.sh
new file mode 100644
index 0000000..2eabe8b
--- /dev/null
+++ b/bash/env.sh
@@ -0,0 +1,78 @@
+#
+# mal (Make a Lisp) environment definition
+#
+
+if [ -z "${__mal_env_included__}" ]; then
+__mal_env_included=true
+
+source $(dirname $0)/types.sh
+
+# Any environment is a hash_map with an __outer__ key that refers to
+# a parent environment (or nil)
+ENV () {
+    r=
+    _hash_map
+    local env="${r}"
+    if [[ "${1}" ]]; then
+        outer="${1}"; shift
+        _assoc! "${env}" "__outer__" "${outer}"
+    else
+        _assoc! "${env}" "__outer__" "${__nil}"
+    fi
+    r="${env}"
+
+    if [[ "${1}" && "${@}" ]]; then
+        local binds=(${ANON["${1}"]}); shift
+        local idx=0
+        while [[ "${binds["${idx}"]}" ]]; do
+            local fp="${ANON["${binds["${idx}"]}"]}"
+            if [[ "${fp}" == "&" ]]; then
+                idx=$(( idx + 1 ))
+                fp="${ANON["${binds["${idx}"]}"]}"
+                _list "${@}"
+                _assoc! "${env}" "${fp}" "${r}"
+                break
+            else
+                _assoc! "${env}" "${fp}" "${1}"
+                shift
+                idx=$(( idx + 1 ))
+            fi
+        done
+    fi
+    r="${env}"
+}
+
+# Find the environment with the key set and return the environment
+ENV_FIND () {
+    if _contains? "${1}" "${2}"; then
+        r="${1}"
+    else
+        local obj="${ANON["${1}"]}"
+        eval local outer="\${${obj}["__outer__"]}"
+        if [[ "${outer}" && "${outer}" != "${__nil}" ]]; then
+            ENV_FIND "${outer}" "${2}"
+        else
+            r=
+        fi
+    fi
+}
+
+# Find the environment with the key set and return the value of the
+# key in that environment. If no environment contains the key then
+# return an error
+ENV_GET () {
+    ENV_FIND "${1}" "${2}"
+    local env="${r}"
+    if [[ "${r}" ]]; then
+        local obj="${ANON["${env}"]}"
+        eval r="\${${obj}["${2}"]}"
+    else
+        _error "'${2}' not found"
+    fi
+}
+
+ENV_SET () {
+    _assoc! "${1}" "${2}" "${3}"
+}
+
+fi