If you want at most MAX repetitions, use {0,MAX}

The reason for the asymmetry between {MIN,} and {,MAX} is probably that there's a zero in perl, but Inf isn't generally supported.

If you wonder what {,MAX} matches, here's the answer: 

$ perl -Mre=debug -ce ' /a{,5}/'
Compiling REx "a{,5}"
Final program:
   1: EXACT <a{,5}> (4)
   4: END (0)
anchored "a{,5}" at 0 (checking anchored isall) minlen 5 
-e syntax OK
Freeing REx: "a{,5}"

$ perl -wE 'say "yes" if "a{,4}" =~ /a{,4}/'
yes

# in contrast:
$ perl -Mre=debug -ce ' /a{0,5}/'
Compiling REx "a{0,5}"
Final program:
   1: CURLY {0,5} (5)
   3:   EXACT <a> (0)
   5: END (0)
minlen 0 
-e syntax OK
Freeing REx: "a{0,5}"

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Perl 6 - second systems done right

In reply to Re: Oddness with regex quantifiers by moritz
in thread Oddness with regex quantifiers by talexb

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