1 files changed, 94 insertions, 0 deletions
diff --git a/php/step3_env.php b/php/step3_env.php
new file mode 100644
index 0000000..15d7c5c
--- /dev/null
+++ b/php/step3_env.php
@@ -0,0 +1,94 @@
+<?php
+
+require_once 'readline.php';
+require_once 'types.php';
+require_once 'reader.php';
+
+// read
+function READ($str) {
+    return read_str($str);
+}
+
+// eval
+function eval_ast($ast, $env) {
+    if (symbol_Q($ast)) {
+        return $env->get($ast->value);
+    } elseif (list_Q($ast) || vector_Q($ast)) {
+        if (list_Q($ast)) {
+            $el = new_list();
+        } else {
+            $el = new_vector();
+        }
+        foreach ($ast as $a) { $el[] = MAL_EVAL($a, $env); }
+        return $el;
+    } elseif (hash_map_Q($ast)) {
+        $new_hm = new_hash_map();
+        foreach (array_keys($ast->getArrayCopy()) as $key) {
+            $new_hm[$key] = MAL_EVAL($ast[$key], $env);
+        }
+        return $new_hm;
+    } else {
+        return $ast;
+    }
+}
+
+function MAL_EVAL($ast, $env) {
+    if (!list_Q($ast)) {
+        return eval_ast($ast, $env);
+    }
+
+    // apply list
+    $a0 = $ast[0];
+    $a0v = (symbol_Q($a0) ? $a0->value : $a0);
+    switch ($a0v) {
+    case "def!":
+        $res = MAL_EVAL($ast[2], $env);
+        return $env->set($ast[1]->value, $res);
+    case "let*":
+        $a1 = $ast[1];
+        $let_env = new Env($env);
+        for ($i=0; $i < count($a1); $i+=2) {
+            $let_env->set($a1[$i]->value, MAL_EVAL($a1[$i+1], $let_env));
+        }
+        return MAL_EVAL($ast[2], $let_env);
+    default:
+        $el = eval_ast($ast, $env);
+        $f = $el[0];
+        return call_user_func_array($f, array_slice($el->getArrayCopy(), 1));
+    }
+}
+
+// print
+function MAL_PRINT($exp) {
+    return _pr_str($exp, True) . "\n";
+}
+
+// repl
+$repl_env = new Env(NULL);
+function rep($str) {
+    global $repl_env;
+    return MAL_PRINT(MAL_EVAL(READ($str), $repl_env));
+}
+function _ref($k, $v) { global $repl_env; $repl_env->set($k, $v); }
+
+_ref('+', function ($a, $b) { return intval($a + $b,10); });
+_ref('-', function ($a, $b) { return intval($a - $b,10); });
+_ref('*', function ($a, $b) { return intval($a * $b,10); });
+_ref('/', function ($a, $b) { return intval($a / $b,10); });
+
+do {
+    try {
+        $line = mal_readline("user> ");
+        if ($line === NULL) { break; }
+        if ($line !== "") {
+            print(rep($line));
+        }
+    } catch (BlankException $e) {
+        continue;
+    } catch (Exception $e) {
+        echo "Error: " . $e->getMessage() . "\n";
+        echo $e->getTraceAsString() . "\n";
+    }
+} while (true);
+
+?>