[elpa] externals/xr 1b26866 1/2: Warn about repetition of repetition

[Mattias Engdegård]

branch: externals/xr
commit 1b26866aad4ceae17da416bd9328641a516c0d6a
Author: Mattias Engdegård <address@hidden>
Commit: Mattias Engdegård <address@hidden>

    Warn about repetition of repetition
    
    Make xr-lint complain about constructs such as a?* as they are
    usually mistakes.
---
 xr-test.el |  5 +++++
 xr.el      | 14 +++++++++++++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/xr-test.el b/xr-test.el
index 7077283..c0a86a2 100644
--- a/xr-test.el
+++ b/xr-test.el
@@ -274,6 +274,11 @@
                  '((0 . "Escaped non-special character `}'")
                    (4 . "Escaped non-special character `a'")
                    (8 . "Escaped non-special character `%'"))))
+  (should (equal (xr-lint "a?+b+?\\(?:c?\\)*d\\{3\\}+e*\\{2,5\\}")
+                '((2 . "Repetition of repetition")
+                  (14 . "Repetition of repetition")
+                  (21 . "Repetition of repetition")
+                  (24 . "Repetition of repetition"))))
   )
 
 (provide 'xr-test)
diff --git a/xr.el b/xr.el
index 60d84b9..6114ee7 100644
--- a/xr.el
+++ b/xr.el
@@ -26,7 +26,7 @@
 ;;
 ;; - Migrating existing code to rx form, for better readability and
 ;;   maintainability
-;; - Understanding complex regexp strings
+;; - Understanding complex regexp strings and finding errors in them
 ;;   
 ;; Please refer to `rx' for more information about the notation.
 ;;
@@ -310,6 +310,12 @@
         (if (and sequence
                  (not (and (eq (car sequence) 'bol) (eq (preceding-char) ?^))))
             (let ((operator (match-string 0)))
+              (when (and (consp (car sequence))
+                         (memq (caar sequence)
+                               '(opt zero-or-more one-or-more
+                                 repeat = >=)))
+                (xr--report warnings (match-beginning 0)
+                            "Repetition of repetition"))
               (goto-char (match-end 0))
               (setq sequence (cons (xr--postfix operator (car sequence))
                                    (cdr sequence))))
@@ -324,6 +330,12 @@
              sequence
              (not (and (eq (car sequence) 'bol) (eq (preceding-char) ?^))))
         (forward-char 2)
+        (when (and (consp (car sequence))
+                   (memq (caar sequence)
+                         '(opt zero-or-more one-or-more
+                               repeat = >=)))
+          (xr--report warnings (match-beginning 0)
+                      "Repetition of repetition"))
         (if (looking-at (rx (opt (group (one-or-more digit)))
                             (opt (group ",")
                                  (opt (group (one-or-more digit))))