[cl-irregsexp-devel] Much better replace that does not copy the main string every replacement

[John Fremlin]

Pushed major rewrite of all replace stuff to common-lisp.net.

Changed my simple benchmarks from being several orders of magnitude
slower than cl-ppcre to being much faster than cl-ppcre.

(defun bench (n &key (convertor 'identity))
  (let ((s (make-string n)))
    (loop for i below n by 2 do
	  (setf (char s i) #\r))
    (let ((s (funcall convertor s)))
      (time
       (cl-irregsexp:match-replace-all s
	 ("r" "replaced"))))))

(defun bench-no-replace (n &key (convertor 'identity))
  (let ((s (make-string n)))
    (loop for i below n by 2 do
	  (setf (char s i) #\r))
    (let ((s (funcall convertor s)))
      (eq s
       (time
	(cl-irregsexp:match-replace-one s
	  ("q" "replaced")))))))

(defun bench-cl-ppcre (n)
  (let ((s (make-string n)))
    (loop for i below n by 2 do
	  (setf (char s i) #\r))
    (time (cl-ppcre:regex-replace-all "r" s "replaced"))))

(defun bench-cl-ppcre-no-replace (n)
  (let ((s (make-string n)))
    (loop for i below n by 2 do
	  (setf (char s i) #\r))
    (time (cl-ppcre:regex-replace-all "q" s "replaced"))))


There is a worrying bug (in SBCL?) that blows up like this in
the find-random test. Guess that should be isolated, but everything
seems fine on ClozureCL so . . . 

  failed AVER: (ZEROP (HASH-TABLE-COUNT #))
This is probably a bug in SBCL itself. (Alternatively, SBCL
might have been corrupted by bad user code, e.g. by an undefined
Lisp operation like (FMAKUNBOUND 'COMPILE), or by stray pointers
from alien code or from unsafe Lisp code; or there might be a
bug in the OS or hardware that SBCL is running on.) If it seems
to be a bug in SBCL itself, the maintainers would like to know
about it. Bug reports are welcome on the SBCL mailing lists,
which you can find at <http://sbcl.sourceforge.net/>.
   [Condition of type SB-INT:BUG]

Restarts:
 0: [RETEST] Rerun the test #<IT.BESE.FIVEAM::TEST-CASE CL-IRREGSEXP::FIND-RANDOM {1004B5FD21}>
 1: [IGNORE] Signal an exceptional test failure and abort the test #<IT.BESE.FIVEAM::TEST-CASE CL-IRREGSEXP::FIND-RANDOM {1004B5FD21}>.
 2: [EXPLAIN] Ignore the rest of the tests and explain current results
 3: [RETRY] Retry SLIME REPL evaluation request.
 4: [ABORT] Return to SLIME's top level.
 5: [TERMINATE-THREAD] Terminate this thread (#<THREAD "repl-thread" RUNNING {1003168441}>)

Backtrace:
  0: (SB-INT:BUG "~@<failed AVER: ~2I~_~A~:>")[:EXTERNAL]
  1: (SB-IMPL::%FAILED-AVER (ZEROP (HASH-TABLE-COUNT (SB-C::CORE-OBJECT-PATCH-TABLE SB-C::OBJECT))))
  2: (SB-C::FIX-CORE-SOURCE-INFO #<SB-C::SOURCE-INFO > #<SB-C::CORE-OBJECT > #<FUNCTION (LAMBDA #) {10032A1089}>)
  3: (SB-C::%COMPILE ..)[:EXTERNAL]


[...]