branch: externals/xr
commit 2c0af48a230a02e4db5439fc9b02c77757f37d03
Author: Mattias Engdegård <matti...@acm.org>
Commit: Mattias Engdegård <matti...@acm.org>
Detect repetition-of-repetition with intervening group
For example, \(.*\)* -- groups are often used even though capture is
not needed. Exception: \(X+\)? does not elicit a warning.
---
xr-test.el | 6 ++++++
xr.el | 27 +++++++++++++++++++++++++++
2 files changed, 33 insertions(+)
diff --git a/xr-test.el b/xr-test.el
index 526740d..f995bfa 100644
--- a/xr-test.el
+++ b/xr-test.el
@@ -363,6 +363,12 @@
'((2 . "Repetition of repetition")
(14 . "Repetition of repetition")
(25 . "Repetition of repetition"))))
+ (should (equal (xr-lint "\\(a*\\)*\\(b+\\)*\\(c*\\)?\\(d+\\)?")
+ '((6 . "Repetition of repetition")
+ (13 . "Repetition of repetition")
+ (20 . "Repetition of repetition"))))
+ (should (equal (xr-lint "\\(e*\\)\\{3\\}")
+ '((6 . "Repetition of repetition"))))
(should (equal (xr-lint "[]-Qa-fz-t]")
'((1 . "Reversed range `]-Q' matches nothing")
(7 . "Reversed range `z-t' matches nothing"))))
diff --git a/xr.el b/xr.el
index 1c74527..abe4d75 100644
--- a/xr.el
+++ b/xr.el
@@ -490,11 +490,27 @@ UPPER may be nil, meaning infinity."
(operand (car sequence)))
(when warnings
(cond
+ ;; (* (* X)), for any repetitions *
((and (consp operand)
(memq (car operand)
'(opt zero-or-more one-or-more +? *? ??)))
(xr--report warnings (match-beginning 0)
"Repetition of repetition"))
+ ;; (* (group (* X))), for any repetitions *
+ ((and (consp operand)
+ (eq (car operand) 'group)
+ (null (cddr operand))
+ (let ((inner (cadr operand)))
+ (and (consp inner)
+ (memq (car inner)
+ '(opt zero-or-more one-or-more +? *? ??))
+ ;; Except (? (group (+ X))), since that may
+ ;; be legitimate.
+ (not (and (equal operator "?")
+ (memq (car inner)
+ '(one-or-more +?)))))))
+ (xr--report warnings (match-beginning 0)
+ "Repetition of repetition"))
((memq operand xr--zero-width-assertions)
(xr--report warnings (match-beginning 0)
"Repetition of zero-width assertion"))
@@ -522,11 +538,22 @@ UPPER may be nil, meaning infinity."
(let ((operand (car sequence)))
(when warnings
(cond
+ ;; (** N M (* X)), for any repetition *
((and (consp operand)
(memq (car operand)
'(opt zero-or-more one-or-more +? *? ??)))
(xr--report warnings (match-beginning 0)
"Repetition of repetition"))
+ ;; (** N M (group (* X))), for any repetition *
+ ((and (consp operand)
+ (eq (car operand) 'group)
+ (null (cddr operand))
+ (let ((inner (cadr operand)))
+ (and (consp inner)
+ (memq (car inner)
+ '(opt zero-or-more one-or-more +? *? ??)))))
+ (xr--report warnings (match-beginning 0)
+ "Repetition of repetition"))
((memq operand xr--zero-width-assertions)
(xr--report warnings (match-beginning 0)
"Repetition of zero-width assertion"))
