From f4e3c0fd0bbaf93cacb0da7b75e35de63fb95f77 Mon Sep 17 00:00:00 2001
From: Alex Shinn <alexshinn@gmail.com>
Date: Mon, 28 Oct 2024 09:16:30 +0900
Subject: [PATCH] Defining and using a repl-print generic to allow customizing
 REPL output.

---
 lib/chibi/repl.scm | 19 ++++++++++++-------
 lib/chibi/repl.sld |  4 ++--
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/lib/chibi/repl.scm b/lib/chibi/repl.scm
index 5c2d5e73..7226f9fb 100644
--- a/lib/chibi/repl.scm
+++ b/lib/chibi/repl.scm
@@ -402,6 +402,11 @@
         ((= (length value) 1) (push-history-value! (car value)))
         (else (push-history-value! value))))
 
+(define-generic repl-print)
+
+(define-method (repl-print obj (out output-port?))
+  (write/ss obj out))
+
 (define (repl/eval rp expr-list)
   (let ((thread (current-thread))
         (out (repl-out rp)))
@@ -422,17 +427,17 @@
                           (null? expr))
                       (eval expr (repl-env rp))
                       expr))
-              (lambda res-list
+              (lambda res-values
                 (cond
-                 ((not (or (null? res-list)
-                           (equal? res-list (list (if #f #f)))))
-                  (push-history-value-maybe! res-list)
-                  (write/ss (car res-list) out)
+                 ((not (or (null? res-values)
+                           (equal? res-values (list undefined-value))))
+                  (push-history-value-maybe! res-values)
+                  (repl-print (car res-values) out)
                   (for-each
                    (lambda (res)
                      (write-char #\space out)
-                     (write/ss res out))
-                   (cdr res-list))
+                     (repl-print res out))
+                   (cdr res-values))
                   (newline out))))))
           expr-list))))))
 
diff --git a/lib/chibi/repl.sld b/lib/chibi/repl.sld
index ae504cba..3e3ff957 100644
--- a/lib/chibi/repl.sld
+++ b/lib/chibi/repl.sld
@@ -1,8 +1,8 @@
 
 (define-library (chibi repl)
-  (export repl $0 $1 $2 $3 $4 $5 $6 $7 $8 $9)
+  (export repl repl-print $0 $1 $2 $3 $4 $5 $6 $7 $8 $9)
   (import (chibi) (only (meta) load-module module-name->file)
-          (chibi ast) (chibi modules) (chibi doc)
+          (chibi ast) (chibi modules) (chibi doc) (chibi generic)
           (chibi string) (chibi io) (chibi optional)
           (chibi process) (chibi term edit-line)
           (srfi 1)