From b36b2ffda71b06c565b9911800d47f5b0c67cf8a Mon Sep 17 00:00:00 2001
From: Iqbal Ansari <iqbalansari02@yahoo.com>
Date: Mon, 15 Aug 2016 14:44:28 +0530
Subject: [PATCH] Teach MAL to read and print vectors

---
 common_lisp/printer.lisp | 16 ++++++++++------
 common_lisp/reader.lisp  | 12 +++++++-----
 common_lisp/types.lisp   |  1 +
 3 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/common_lisp/printer.lisp b/common_lisp/printer.lisp
index fbda2f44..ec2ffa69 100644
--- a/common_lisp/printer.lisp
+++ b/common_lisp/printer.lisp
@@ -6,6 +6,14 @@
 
 (in-package :printer)
 
+(defun pr-mal-sequence (start-delimiter sequence end-delimiter)
+  (concatenate 'string
+               start-delimiter
+               (format nil
+                       "~{~A~^ ~}"
+                       (mapcar #'pr-str (types::mal-value sequence)))
+               end-delimiter))
+
 (defun pr-str (ast)
   (when ast
     (case (types::mal-type ast)
@@ -14,9 +22,5 @@
       ('nil "nil")
       ('string (format nil "~s" (types::mal-value ast)))
       ('symbol (format nil "~a" (types::mal-value ast)))
-      ('list (concatenate 'string
-                          "("
-                          (format nil
-                                  "~{~A~^ ~}"
-                                  (mapcar #'pr-str (types::mal-value ast)))
-                          ")")))))
+      ('list (pr-mal-sequence "(" ast ")"))
+      ('vector (pr-mal-sequence "[" ast "]")))))
diff --git a/common_lisp/reader.lisp b/common_lisp/reader.lisp
index 45789315..03285cd6 100644
--- a/common_lisp/reader.lisp
+++ b/common_lisp/reader.lisp
@@ -80,22 +80,24 @@
   (let ((token (peek reader)))
     (cond
       ((null token) nil)
-      ((string= token "(") (read-list reader))
+      ((string= token "(") (make-mal-list (read-mal-sequence reader)))
+      ((string= token "[") (make-mal-vector (read-mal-sequence reader "]")))
       (t (read-atom reader)))))
 
-(defun read-list (reader)
+(defun read-mal-sequence (reader &optional (delimiter ")"))
   ;; Consume the open brace
   (consume reader)
   (let (forms)
     (loop
        for token = (peek reader)
        while (cond
-               ((null token) (error 'eof :text "EOF encountered while reading list"))
-               ((string= token ")") (return))
+               ((null token) (error 'eof :text (format "EOF encountered while reading list, expected ~a"
+                                                       delimiter)))
+               ((string= token delimiter) (return))
                (t (push (read-form reader) forms))))
     ;; Consume the closing brace
     (consume reader)
-    (make-mal-list (nreverse forms))))
+    (nreverse forms)))
 
 (defun read-atom (reader)
   (let ((token (next reader)))
diff --git a/common_lisp/types.lisp b/common_lisp/types.lisp
index 7148a3ed..fd3253e2 100644
--- a/common_lisp/types.lisp
+++ b/common_lisp/types.lisp
@@ -29,6 +29,7 @@
             (export ',constructor))))
 
 (define-mal-type list)
+(define-mal-type vector)
 (define-mal-type number)
 (define-mal-type symbol)
 (define-mal-type string)