From 330fda671534ffd36e262429847917b5ae2782d5 Mon Sep 17 00:00:00 2001
From: Pekka Laiho <pekka.i.laiho@gmail.com>
Date: Sat, 24 Oct 2020 14:27:02 +0700
Subject: [PATCH] support for init file

---
 README.md    | 10 +++++++++-
 run.php      |  8 +++++++-
 src/Lisp.php | 10 ++++++++--
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index e1ee750..509583c 100644
--- a/README.md
+++ b/README.md
@@ -18,7 +18,7 @@ The core project does not have any dependencies to external [Composer](https://g
 
 ## Usage
 
-Use the **run.php** file to invoke the interpreter. You can start the Repl with the -r switch:
+Use the **run.php** file to invoke the interpreter from the command line. You can start the Repl with the -r switch:
 
 ```
 $ php run.php -r
@@ -44,6 +44,14 @@ $ echo "(+ 1 2 3)" | php run.php
 6
 ```
 
+## Init file
+
+You can create an init file in your home directory with the name `.madlisp_init`. This file is automatically executed when the interpreter is started. It is useful for registering commonly used functions and performing other initialization.
+
+## Using from PHP
+
+You can use the [LispFactory](src/LispFactory.php) class to create an instance of the interpreter if you wish to embed the MadLisp language in your PHP application and call it directly from your code.
+
 ## Types
 
 ### Numbers
diff --git a/run.php b/run.php
index 0e2d7b1..cf8ce4d 100644
--- a/run.php
+++ b/run.php
@@ -8,7 +8,7 @@ if (php_sapi_name() != 'cli') {
 function ml_repl($lisp)
 {
     // Read history
-    $historyFile = $_SERVER['HOME'] . '/.madlisp_history';
+    $historyFile = $_SERVER['HOME'] . DIRECTORY_SEPARATOR . '.madlisp_history';
     if (is_readable($historyFile)) {
         readline_read_history($historyFile);
     }
@@ -37,6 +37,12 @@ function ml_repl($lisp)
 $factory = new MadLisp\LispFactory();
 $lisp = $factory->make();
 
+// Load the user's init file if present
+$initfile = $_SERVER['HOME'] . DIRECTORY_SEPARATOR . '.madlisp_init';
+if (is_readable($initfile)) {
+    $lisp->readEval("(load \"$initfile\")");
+}
+
 if ($argc < 2) {
     // Read input from stdin
     $input = file_get_contents('php://stdin');
diff --git a/src/Lisp.php b/src/Lisp.php
index 2e3d559..1263d99 100644
--- a/src/Lisp.php
+++ b/src/Lisp.php
@@ -18,13 +18,19 @@ class Lisp
         $this->env = $env;
     }
 
-    public function rep(string $input, bool $printReadable): void
+    public function readEval(string $input)
     {
         $tokens = $this->tokenizer->tokenize($input);
 
         $expr = $this->reader->read($tokens);
 
-        $result = $this->eval->eval($expr, $this->env);
+        return $this->eval->eval($expr, $this->env);
+    }
+
+    // read, eval, print
+    public function rep(string $input, bool $printReadable): void
+    {
+        $result = $this->readEval($input);
 
         $this->printer->print($result, $printReadable);
     }