use re 'debug';
$s = 'xfx';
while ($s =~ / (f*?) /gx) {


##</code><code>##

Compiling REx " (f*?) "
Final program:
   1: OPEN1 (3)
   3:   MINMOD (4)
   4:   STAR (7)
   5:     EXACT <f> (0)
   7: CLOSE1 (9)
   9: END (0)
minlen 0 
xfx
------------
Matching REx " (f*?) " against "xfx"
   0 <> <xfx>                |  1:OPEN1(3)
   0 <> <xfx>                |  3:MINMOD(4)
   0 <> <xfx>                |  4:STAR(7)
   0 <> <xfx>                |  7:  CLOSE1(9)
   0 <> <xfx>                |  9:  END(0)
Match successful!
matched (f*?) of "", starting at offset of 0, ending at pos of 0 
Matching REx " (f*?) " against "xfx"
   0 <> <xfx>                |  1:OPEN1(3)
   0 <> <xfx>                |  3:MINMOD(4)
   0 <> <xfx>                |  4:STAR(7)
   0 <> <xfx>                |  7:  CLOSE1(9)
   0 <> <xfx>                |  9:  END(0)
Match possible, but length=0 is smaller than requested=1, failing!
                                  EXACT <f> can match 0 times out of 1...
                                  failed...
   1 <x> <fx>                |  1:OPEN1(3)
   1 <x> <fx>                |  3:MINMOD(4)
   1 <x> <fx>                |  4:STAR(7)
   1 <x> <fx>                |  7:  CLOSE1(9)
   1 <x> <fx>                |  9:  END(0)
Match successful!
matched (f*?) of "", starting at offset of 1, ending at pos of 1 
Matching REx " (f*?) " against "fx"
   1 <x> <fx>                |  1:OPEN1(3)
   1 <x> <fx>                |  3:MINMOD(4)
   1 <x> <fx>                |  4:STAR(7)
   1 <x> <fx>                |  7:  CLOSE1(9)
   1 <x> <fx>                |  9:  END(0)
Match possible, but length=0 is smaller than requested=1, failing!
                                  EXACT <f> can match 1 times out of 1...
   2 <xf> <x>                |  7:  CLOSE1(9)
   2 <xf> <x>                |  9:  END(0)
Match successful!
matched (f*?) of "f", starting at offset of 1, ending at pos of 2 
Matching REx " (f*?) " against "x"
   2 <xf> <x>                |  1:OPEN1(3)
   2 <xf> <x>                |  3:MINMOD(4)
   2 <xf> <x>                |  4:STAR(7)
   2 <xf> <x>                |  7:  CLOSE1(9)
   2 <xf> <x>                |  9:  END(0)
Match successful!
matched (f*?) of "", starting at offset of 2, ending at pos of 2 
Matching REx " (f*?) " against "x"
   2 <xf> <x>                |  1:OPEN1(3)
   2 <xf> <x>                |  3:MINMOD(4)
   2 <xf> <x>                |  4:STAR(7)
   2 <xf> <x>                |  7:  CLOSE1(9)
   2 <xf> <x>                |  9:  END(0)
Match possible, but length=0 is smaller than requested=1, failing!
                                  EXACT <f> can match 0 times out of 1...
                                  failed...
   3 <xfx> <>                |  1:OPEN1(3)
   3 <xfx> <>                |  3:MINMOD(4)
   3 <xfx> <>                |  4:STAR(7)
   3 <xfx> <>                |  7:  CLOSE1(9)
   3 <xfx> <>                |  9:  END(0)
Match successful!
matched (f*?) of "", starting at offset of 3, ending at pos of 3 
Matching REx " (f*?) " against ""
   3 <xfx> <>                |  1:OPEN1(3)
   3 <xfx> <>                |  3:MINMOD(4)
   3 <xfx> <>                |  4:STAR(7)
   3 <xfx> <>                |  7:  CLOSE1(9)
   3 <xfx> <>                |  9:  END(0)
Match possible, but length=0 is smaller than requested=1, failing!
                                  EXACT <f> can match 0 times out of 1...
                                  failed...
Match failed
Freeing REx: " (f*?) "


##</code><code>##

Match possible, but length=0 is smaller than requested=1, failing!


##</code><code>##

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,