From f7286183368205e6488316bee3242f0344c33588 Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Tue, 20 Dec 2022 21:44:27 -0500
Subject: [PATCH] Issue #498 - read-line can read 1022+ byte lines

Previously the function would only read up to the first 1022 bytes. We now remove that restriction
---
 CHANGELOG.md    |  1 +
 scheme/base.sld | 23 ++++++++++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1f39c1f7..5d7f90ed 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 Bug Fixes
 
+- Fix `read-line` to read entire lines that consist of more than 1022 bytes. Previously the function would only return partial data up to this limit. Thanks to Robby Zambito for the bug report.
 - `(include "body.scm")` inside a file `path/to/lib.sld` will look for `path/to/body.scm`, then fallback to the legacy behavior, and look for `$(pwd)/body.scm`.
 - Pass append and prepend directories when compiling dependent libraries of a program. This prevents issues where the directories are not made available to any `include` directives within such libraries.
 
diff --git a/scheme/base.sld b/scheme/base.sld
index b4ec756b..13631ec7 100644
--- a/scheme/base.sld
+++ b/scheme/base.sld
@@ -695,9 +695,26 @@
         (Cyc-read-char (current-input-port))
         (Cyc-read-char (car port))))
     (define (read-line . port)
-      (if (null? port)
-        (Cyc-read-line (current-input-port))
-        (Cyc-read-line (car port))))
+      (let* ((p (if (null? port)
+                   (current-input-port)
+                   (car port)))
+             (str (Cyc-read-line p)))
+        (cond
+          ((eof-object? str) str)
+          ((< (string-length str) 1022) str)
+          (else (_read-line str p)))))
+    ;; Helper function to handle case where a line is too
+    ;; long to be read by a single runtime I/O call
+    (define (_read-line str port)
+      (let loop ((lis (list str))
+                 (str (Cyc-read-line port)))
+        (cond
+          ((eof-object? str)
+           (apply string-append (reverse lis)))
+          ((< (string-length str) 1022)
+           (apply string-append (reverse (cons str lis))))
+          (else
+            (loop (cons str lis) (Cyc-read-line port))))))
     (define (read-string k . opts)
       (let ((port (if (null? opts)
                       (current-input-port)