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, 56 insertions, 0 deletions

diff --git a/php/env.php b/php/env.php
new file mode 100644
index 0000000..61bedaf
--- /dev/null
+++ b/php/env.php
@@ -0,0 +1,56 @@
+<?php
+
+require_once 'types.php';
+
+class Env {
+    public $data = array();
+    public $outer = NULL;
+    public function __construct($outer, $binds=NULL, $exprs=NULL) {
+        $this->outer = $outer;
+        if ($binds) {
+            if (_sequential_Q($exprs)) {
+                $exprs = $exprs->getArrayCopy();
+            }
+            for ($i=0; $i<count($binds); $i++) {
+                if ($binds[$i]->value === "&") {
+                    if ($exprs !== NULL && $i < count($exprs)) {
+                        $lst = call_user_func_array('_list', array_slice($exprs, $i));
+                    } else {
+                        $lst = _list();
+                    }
+                    $this->data[$binds[$i+1]->value] = $lst;
+                    break;
+                } else {
+                    if ($exprs !== NULL && $i < count($exprs)) {
+                        $this->data[$binds[$i]->value] = $exprs[$i];
+                    } else {
+                        $this->data[$binds[$i]->value] = NULL;
+                    }
+                }
+            }
+        }
+    }
+    public function find($key) {
+        if (array_key_exists($key, $this->data)) {
+            return $this;
+        } elseif ($this->outer) {
+            return $this->outer->find($key);
+        } else {
+            return NULL;
+        }
+    }
+    public function set($key, $value) {
+        $this->data[$key] = $value;
+        return $value;
+    }
+    public function get($key) {
+        $env = $this->find($key);
+        if (!$env) {
+            throw new Exception("'" . $key . "' not found");
+        } else {
+            return $env->data[$key];
+        }
+    }
+}
+
+?>