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Timestamp:
2006年05月18日 16時19分18秒 (3 years ago)
Author:
miyoshi
Message:

Sync up with Emacs CVS HEAD.

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  • trunk/lispref/searching.texi

    r4073 r4085  
    307307@samp{ar} and there is only @samp{r} left to match, so this try fails. 
    308308The next alternative is for @samp{a*} to match only two @samp{a}s.  With 
    309 this choice, the rest of the regexp matches successfully.@refill 
    310  
    311 Nested repetition operators take a long time, or even forever, if they 
     309this choice, the rest of the regexp matches successfully. 
     310 
     311@strong{Warning:} Nested repetition operators take a long time, 
     312or even forever, if they 
    312313lead to ambiguous matching.  For example, trying to match the regular 
    313314expression @samp{\(x+y*\)*a} against the string 
     
    317318@samp{\(x*\)*} can match the null string in infinitely many ways, so 
    318319it causes an infinite loop.  To avoid these problems, check nested 
    319 repetitions carefully. 
     320repetitions carefully, to make sure that they do not cause combinatorial 
     321explosions in backtracking. 
    320322 
    321323@item @samp{+}