From: Chris Hanson <org/chris-hanson/cph>
Date: Tue, 19 Nov 2019 06:46:03 +0000 (-0800)
Subject: Allow string-builder to take a zero argument.
X-Git-Tag: mit-scheme-pucked-10.1.20~11^2~3
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=b52ecd51f28d1530073d155670bad2919f2cfca6;p=mit-scheme.git

Allow string-builder to take a zero argument.

This simplifies cases where the length of the result is known in advance and
passed as the buffer size.
---

diff --git a/src/runtime/string.scm b/src/runtime/string.scm
index 5e78396e2..660da8ec5 100644
--- a/src/runtime/string.scm
+++ b/src/runtime/string.scm
@@ -590,8 +590,8 @@ USA.
 	  (if (default-object? buffer-length)
 	      1024
 	      (begin
-		(guarantee positive-fixnum? buffer-length 'string-builder)
-		buffer-length)))))
+		(guarantee non-negative-fixnum? buffer-length 'string-builder)
+		(fix:max 1 buffer-length))))))
     (let ((append-char! (builder 'append-char!))
 	  (append-string! (builder 'append-string!))
 	  (build (builder 'build)))