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goafteru wrote:

It is mentioned  in the manual:
"a single character class followed by '*', which matches 0 or more repetitions of characters in the class. 
These repetition items will always match the longest possible sequence;"
I think the empty string after "abc" should not be matched in lua, just like in other programmes (such as: sed,gawk) .
You have a badly-written regex. I hardly ever use a '*' in an matching or substitution iterator unless its for consuming whitespace. If you are pattern-matching "something that is expected to be there", it's '+' and not '*'. If your regex is too vague, it will usually end up matching in too promiscuous a manner. 


------------------ 原始邮件 ------------------
*发件人:* "Patrick Donnelly"<batrick@batbytes.com>;
*发送时间:* 2009年12月27日(星期天) 下午3:20
*收件人:* "Lua list"<lua@bazar2.conectiva.com.br>;
*主题:* Re: A bug in pattern matching ??
On Sun, Dec 27, 2009 at 12:13 AM, goafteru <goafteru@qq.com> wrote: 
 >
 > print ( string.gsub("abc", "%w*", "@") )
 >
 > and the result is:
 > @@ 2
 >
 > rather than:
 > @ 1

%w* can match the empty string, which it does after abc matches.


--
-Patrick Donnelly


--
Cheers,
Kein-Hong Man (esq.)
Kuala Lumpur, Malaysia