string-view utility

2 files changed, 7 insertions, 6 deletions

diff --git a/src/lexer.lisp b/src/lexer.lisp
index cd47881..3865cd6 100644
--- a/src/lexer.lisp
+++ b/src/lexer.lisp
@@ -103,18 +103,14 @@
     (lexer-read l)
     (loop :while (digit? (ch l))
           :do (lexer-read l))
-    (make-array (- (pos l) start) :element-type 'character
-                                    :displaced-to (input l)
-                                    :displaced-index-offset start)))
+    (make-string-view (input l) start (pos l))))
 
 (defmethod read-identifier ((l lexer))
   (let ((start (pos l)))
     (lexer-read l)
     (loop :while (letter? (ch l))
           :do (lexer-read l))
-    (make-array (- (pos l) start) :element-type 'character
-                                    :displaced-to (input l)
-                                    :displaced-index-offset start)))
+    (make-string-view (input l) start (pos l))))
 
 
 (defmethod lexer-tokens ((l lexer))
diff --git a/src/util.lisp b/src/util.lisp
index d58cde8..cf3bc76 100644
--- a/src/util.lisp
+++ b/src/util.lisp
@@ -8,6 +8,11 @@
     `(eval-when (:compile-toplevel :load-toplevel :execute)
        ,@body)))
 
+(defun make-string-view (source start end)
+  (make-array (- end start) :element-type 'character
+              :displaced-to source
+              :displaced-index-offset start))
+
 (defun read-file-contents (file-name)
   (let* ((len 0)
          (contents