From 51797cec094d642600e9f86c517eb5a6883f5358 Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Mon, 19 Apr 2010 19:33:57 +0200
Subject: [PATCH] make-record-type slight refactor

* test-suite/tests/records.test ("records"): Add tests for printers.

* module/ice-9/boot-9.scm (make-record-type): Refactor the code that
  makes the default printer.
---
 module/ice-9/boot-9.scm       | 55 ++++++++++++++++++-----------------
 test-suite/tests/records.test | 26 +++++++++++++----
 2 files changed, 49 insertions(+), 32 deletions(-)

diff --git a/module/ice-9/boot-9.scm b/module/ice-9/boot-9.scm
index 4beec1e64..58c6c5c51 100644
--- a/module/ice-9/boot-9.scm
+++ b/module/ice-9/boot-9.scm
@@ -649,33 +649,34 @@ If there is no handler at all, Guile prints an error and then exits."
   (and (struct? obj) (eq? record-type-vtable (struct-vtable obj))))
 
 (define (make-record-type type-name fields . opt)
-  (let ((printer-fn (and (pair? opt) (car opt))))
-    (let ((struct (make-struct record-type-vtable 0
-                               (make-struct-layout
-                                (apply string-append
-                                       (map (lambda (f) "pw") fields)))
-                               (or printer-fn
-                                   (lambda (s p)
-                                     (display "#<" p)
-                                     (display type-name p)
-                                     (let loop ((fields fields)
-                                                (off 0))
-                                       (cond
-                                        ((not (null? fields))
-                                         (display " " p)
-                                         (display (car fields) p)
-                                         (display ": " p)
-                                         (display (struct-ref s off) p)
-                                         (loop (cdr fields) (+ 1 off)))))
-                                     (display ">" p)))
-                               type-name
-                               (copy-tree fields))))
-      ;; Temporary solution: Associate a name to the record type descriptor
-      ;; so that the object system can create a wrapper class for it.
-      (set-struct-vtable-name! struct (if (symbol? type-name)
-                                          type-name
-                                          (string->symbol type-name)))
-      struct)))
+  (define (default-record-printer s p)
+    (display "#<" p)
+    (display (record-type-name (record-type-descriptor s)) p)
+    (let loop ((fields (record-type-fields (record-type-descriptor s)))
+               (off 0))
+      (cond
+       ((not (null? fields))
+        (display " " p)
+        (display (car fields) p)
+        (display ": " p)
+        (display (struct-ref s off) p)
+        (loop (cdr fields) (+ 1 off)))))
+    (display ">" p))
+
+  (let ((struct (make-struct record-type-vtable 0
+                             (make-struct-layout
+                              (apply string-append
+                                     (map (lambda (f) "pw") fields)))
+                             (or (and (pair? opt) (car opt))
+                                 default-record-printer)
+                             type-name
+                             (copy-tree fields))))
+    ;; Temporary solution: Associate a name to the record type descriptor
+    ;; so that the object system can create a wrapper class for it.
+    (set-struct-vtable-name! struct (if (symbol? type-name)
+                                        type-name
+                                        (string->symbol type-name)))
+    struct))
 
 (define (record-type-name obj)
   (if (record-type? obj)
diff --git a/test-suite/tests/records.test b/test-suite/tests/records.test
index 7f8e63621..c2ea06ed7 100644
--- a/test-suite/tests/records.test
+++ b/test-suite/tests/records.test
@@ -1,6 +1,6 @@
 ;;;; records.test --- Test suite for Guile's records. -*- mode: scheme; coding: utf-8 -*-
 ;;;;
-;;;; Copyright (C) 2009 Free Software Foundation, Inc.
+;;;; Copyright (C) 2009, 2010 Free Software Foundation, Inc.
 ;;;; 
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -17,10 +17,13 @@
 ;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 
 (define-module (test-records)
+  #:use-module (ice-9 format)
   #:use-module (test-suite lib))
 
-;; ascii names and symbols
-(define rtd-foo (make-record-type "foo" '(x y)))
+;; ascii names and symbols, custom printer
+(define rtd-foo (make-record-type "foo" '(x y)
+                                  (lambda (s p)
+                                    (display "#<it is a foo>" p))))
 (define make-foo (record-constructor rtd-foo))
 (define foo? (record-predicate rtd-foo))
 (define get-foo-x (record-accessor rtd-foo 'x))
@@ -28,7 +31,7 @@
 (define set-foo-x! (record-modifier rtd-foo 'x))
 (define set-foo-y! (record-modifier rtd-foo 'y))
 
-;; non-Latin-1 names and symbols
+;; non-Latin-1 names and symbols, default printer
 (define rtd-fŏŏ (make-record-type "fŏŏ" '(x ȳ)))
 (define make-fŏŏ (record-constructor rtd-fŏŏ))
 (define fŏŏ? (record-predicate rtd-fŏŏ))
@@ -71,4 +74,17 @@
       (string=? "foo" (record-type-name rtd-foo)))
 
     (pass-if "fŏŏ"
-      (string=? "fŏŏ" (record-type-name rtd-fŏŏ)))))
+      (string=? "fŏŏ" (record-type-name rtd-fŏŏ))))
+
+  (with-test-prefix "printer"
+
+    (pass-if "foo"
+      (string=? "#<it is a foo>"
+                (with-output-to-string
+                  (lambda () (display (make-foo 1 2))))))
+
+    (pass-if "fŏŏ"
+      (with-locale "en_US.utf8"
+        (string-prefix? "#<fŏŏ"
+                        (with-output-to-string
+                          (lambda () (display (make-fŏŏ 1 2)))))))))