From: Mark Thom <markjordanthom@gmail.com>
Date: Sun, 28 Nov 2021 17:21:07 +0000 (-0700)
Subject: keep cursor position after writing to byte stream
X-Git-Tag: v0.9.0^2~115
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=a87236fea27922cfa4fc07784e6d64c55cbde920;p=scryer-prolog.git

keep cursor position after writing to byte stream
---

diff --git a/src/machine/streams.rs b/src/machine/streams.rs
index 4aeba63e..8e2e2c13 100644
--- a/src/machine/streams.rs
+++ b/src/machine/streams.rs
@@ -110,7 +110,13 @@ impl Read for ByteStream {
 impl Write for ByteStream {
     #[inline]
     fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
-        self.0.write(buf)
+        let pos = self.0.position();
+
+        self.0.seek(SeekFrom::End(0))?;
+        let result = self.0.write(buf);
+        self.0.seek(SeekFrom::Start(pos))?;
+
+        result
     }
 
     #[inline]