From: Bart Schaefer <schaefer@brasslantern.com>
To: Zsh hackers list <zsh-workers@zsh.org>
Subject: Re: [BUG] Long line makes pattern matching (by //) hog Zsh
Date: Sun, 5 Jun 2016 12:10:20 -0700 [thread overview]
Message-ID: <160605121020.ZM7727@torch.brasslantern.com> (raw)
In-Reply-To: <CAKc7PVC=AES1LhY7tYTXrPsefX3CXgtUsxiVbDaxmc5o2iHnVw@mail.gmail.com>
On Jun 5, 4:36pm, Sebastian Gniazdowski wrote:
}
} 1. not backslash nor slash nor space [^ /\\\\]##
} 2. not number, slash, backslash, space [^0-9/\\\\ ]##
} 3. not slash, backslash [^/\\\\]#
} 4. end of line (#e)
It's in the block in pattern.c:patchmatch() that begins with the
comment:
/*
* Lookahead to avoid useless matches. This is not possible
* with approximation.
*/
Specifically, in the "if (no >= min) for (;;) ..." loop, at each charater
in the input string patmatch() is called recursively to look at the rest
of the string, which again enters this same loop because the next thing
is also a one-or-more expression, which calls recursively and again
enters the loop because the thing after that is a zero-or-more.
It consumes a LOT of memory while doing this, even if I add a hack to
prevent it from recursively re-entering lookahead (or to skip the
lookahead entirely).
next prev parent reply other threads:[~2016-06-05 19:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-05 14:36 Sebastian Gniazdowski
2016-06-05 19:10 ` Bart Schaefer [this message]
2016-06-05 19:37 ` Peter Stephenson
2016-06-05 20:39 ` Peter Stephenson
2016-06-05 21:21 ` Sebastian Gniazdowski
2016-06-06 0:07 ` Bart Schaefer
2016-06-05 19:47 ` Sebastian Gniazdowski
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