rename some identifiers

beautiful-racket-demo/basic-demo-2/colorer.rkt

@@ -3,16 +3,21 @@
 (provide basic-colorer)
 
 (define (basic-colorer port)
-  (define (handle-lexer-error exn)
-    (define exn-srclocs (exn:fail:read-srclocs exn))
-    (srcloc-token (token 'ERROR) (car exn-srclocs)))
-  (define srcloc-tok (with-handlers ([exn:fail:read? handle-lexer-error])
-                       (basic-lexer port)))
+  (define (handle-lexer-error excn)
+    (define excn-srclocs (exn:fail:read-srclocs excn))
+    (srcloc-token (token 'ERROR) (car excn-srclocs)))
+  (define srcloc-tok
+    (with-handlers ([exn:fail:read? handle-lexer-error])
+      (basic-lexer port)))
   (match srcloc-tok
     [(? eof-object?) (values srcloc-tok 'eof #f #f #f)]
     [else
-     (match-define (srcloc-token (token-struct type val _ _ _ _ _)
-                                 (srcloc _ _ _ pos span)) srcloc-tok)
+     (match-define
+       (srcloc-token
+        (token-struct type val _ _ _ _ _)
+        (srcloc _ _ _ posn span)) srcloc-tok)
+     (define start posn)
+     (define end (+ start span))
      (match-define (list cat paren)
        (match type
          ['STRING '(string #f)]
@@ -24,4 +29,4 @@
                  ["(" '(parenthesis |(|)]
                  [")" '(parenthesis |)|)]
                  [else '(no-color #f)])]))
-     (values val cat paren pos (+ pos span))]))
+     (values val cat paren start end)]))