Issue #465 - Avoid trigraphs in compiled strings

CHANGELOG.md

@@ -6,6 +6,7 @@ Bug Fixes
 
 - Fix `read-line` to prevent data loss when used in conjunction with other I/O functions (such as `read-char`) to read from the same port. Previous versions of `read-line` would use a different internal buffer than our other I/O functions.
 - Properly handle literal vectors at the top level of compiled code.
+- Properly escape C strings in compiled code to avoid trigraphs.
 
 ## 0.30.0 - July 2, 2021
 

scheme/cyclone/cgen.sld

@@ -69,6 +69,8 @@
   (letrec ((next (lambda (head tail)
                    (cond
                      ((null? head) (list->string (reverse tail)))
+                     ((equal? (car head) #\?) ;; Escape ? to avoid trigraphs
+                      (next (cdr head) (cons #\? (cons #\\ tail))))
                      ((equal? (car head) #\")
                       (next (cdr head) (cons #\" (cons #\\ tail))))
                      ((equal? (car head) #\\)