From 4daf4664cfe09eddd577537aa16da64ab1096c29 Mon Sep 17 00:00:00 2001
From: Daniel Llorens <lloda@sarc.name>
Date: Fri, 29 Sep 2023 16:49:57 +0200
Subject: [PATCH] Add test for r7rs string-for-each

* test-suite/tests/r7rs.test: As stated.
* module/scheme/base.scm: Reindent and add minimal doc.
---
 module/scheme/base.scm     | 37 +++++++++++++++++++------------------
 test-suite/tests/r7rs.test |  8 ++++++++
 2 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/module/scheme/base.scm b/module/scheme/base.scm
index 9ad16a371..477dd9c28 100644
--- a/module/scheme/base.scm
+++ b/module/scheme/base.scm
@@ -406,24 +406,25 @@
                                                           s*)))))
 
 (define r7:string-for-each
-      (case-lambda
-        ((proc s) (string-for-each proc s))
-        ((proc s1 s2)
-         (let ((len (min (string-length s1)
-                         (string-length s2))))
-           (let loop ((i 0))
-             (when (< i len)
-               (proc (string-ref s1 i)
-                     (string-ref s2 i))
-               (loop (+ i 1))))))
-        ((proc . strings)
-         (let ((len (apply min (map string-length strings))))
-           (let loop ((i 0))
-             (when (< i len)
-               (apply proc (map (lambda (s)
-                                  (string-ref s i))
-                                strings))
-               (loop (+ i 1))))))))
+  (case-lambda
+   "Like @code{for-each}, but takes strings instead of lists."
+   ((proc s) (string-for-each proc s))
+   ((proc s1 s2)
+    (let ((len (min (string-length s1)
+                    (string-length s2))))
+      (let loop ((i 0))
+        (when (< i len)
+          (proc (string-ref s1 i)
+                (string-ref s2 i))
+          (loop (+ i 1))))))
+   ((proc . strings)
+    (let ((len (apply min (map string-length strings))))
+      (let loop ((i 0))
+        (when (< i len)
+          (apply proc (map (lambda (s)
+                             (string-ref s i))
+                        strings))
+          (loop (+ i 1))))))))
 
 (define (bytevector . lis)
   (u8-list->bytevector lis))
diff --git a/test-suite/tests/r7rs.test b/test-suite/tests/r7rs.test
index 1cc8cd31e..a092473f2 100644
--- a/test-suite/tests/r7rs.test
+++ b/test-suite/tests/r7rs.test
@@ -1773,6 +1773,14 @@
        "abcde")
       v))
 
+(test '(4 3 2 1)
+    (let ((v '()))
+      (string-for-each
+       (lambda (b c) (set! v (cons (- (char->integer b) (char->integer c)) v)))
+       "bdfh"
+       "abcde")
+      v))
+
 (test '(0 1 4 9 16) (let ((v (make-list 5)))
   (vector-for-each
    (lambda (i) (list-set! v i (* i i)))