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<?php
require_once 'readline.php';
require_once 'types.php';
require_once 'reader.php';
require_once 'printer.php';
require_once 'env.php';
require_once 'core.php';
// read
function READ($str) {
return read_str($str);
}
// eval
function eval_ast($ast, $env) {
if (_symbol_Q($ast)) {
return $env->get($ast);
} elseif (_sequential_Q($ast)) {
if (_list_Q($ast)) {
$el = _list();
} else {
$el = _vector();
}
foreach ($ast as $a) { $el[] = MAL_EVAL($a, $env); }
return $el;
} elseif (_hash_map_Q($ast)) {
$new_hm = _hash_map();
foreach (array_keys($ast->getArrayCopy()) as $key) {
$new_hm[$key] = MAL_EVAL($ast[$key], $env);
}
return $new_hm;
} else {
return $ast;
}
}
function MAL_EVAL($ast, $env) {
#echo "MAL_EVAL: " . _pr_str($ast) . "\n";
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], $res);
case "let*":
$a1 = $ast[1];
$let_env = new Env($env);
for ($i=0; $i < count($a1); $i+=2) {
$let_env->set($a1[$i], MAL_EVAL($a1[$i+1], $let_env));
}
return MAL_EVAL($ast[2], $let_env);
case "do":
#$el = eval_ast(array_slice($ast->getArrayCopy(), 1), $env);
$el = eval_ast($ast->slice(1), $env);
return $el[count($el)-1];
case "if":
$cond = MAL_EVAL($ast[1], $env);
if ($cond === NULL || $cond === false) {
if (count($ast) === 4) { return MAL_EVAL($ast[3], $env); }
else { return NULL; }
} else {
return MAL_EVAL($ast[2], $env);
}
case "fn*":
return function() use ($env, $ast) {
$fn_env = new Env($env, $ast[1], func_get_args());
return MAL_EVAL($ast[2], $fn_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);
}
// repl
$repl_env = new Env(NULL);
function rep($str) {
global $repl_env;
return MAL_PRINT(MAL_EVAL(READ($str), $repl_env));
}
// core.php: defined using PHP
foreach ($core_ns as $k=>$v) {
$repl_env->set(_symbol($k), _function($v));
}
// core.mal: defined using the language itself
rep("(def! not (fn* (a) (if a false true)))");
// repl loop
do {
try {
$line = mal_readline("user> ");
if ($line === NULL) { break; }
if ($line !== "") {
print(rep($line) . "\n");
}
} catch (BlankException $e) {
continue;
} catch (Exception $e) {
echo "Error: " . $e->getMessage() . "\n";
echo $e->getTraceAsString() . "\n";
}
} while (true);
?>
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