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<span style="text-decoration:underline;">Compiling REx</span> &quot;<span style="font-weight:bold;">(\d)(?=(\d{3})+(?!\d))</span>&quot;
Final program:
   1: OPEN1 (3)
   3:   POSIXD[\d] (4)
   4: CLOSE1 (6)
   6: IFMATCH[0] (26)
   8:   CURLYM[2] {1,32767} (19)
  12:     CURLY {3,3} (17)
  14:       POSIXD[\d] (0)
  17:     SUCCEED (0)
  18:   NOTHING (19)
  19:   UNLESSM[0] (24)
  21:     POSIXD[\d] (22)
  22:     SUCCEED (0)
  23:   TAIL (24)
  24:   SUCCEED (0)
  25: TAIL (26)
  26: END (0)
stclass POSIXD[\d] minlen 1 
<span style="text-decoration:underline;">Matching REx</span> &quot;<span style="font-weight:bold;">(\d)(?=(\d{3})+(?!\d))</span>&quot; against &quot;<span style="font-weight:bold;">1231231.23</span>&quot;
Matching stclass POSIXD[\d] against &quot;<span style="font-weight:bold;">1231231.23</span>&quot; (10 bytes)
   0 &lt;<span style="text-decoration:underline;"></span><span style="color:gray;background-color:black;"></span><span style="color:black;background-color:gray;"></span><span style="color:black;background-color:gray;font-weight:bold;">1231231.23</span>&gt;|  1:OPEN1(3)
   0 &lt;<span style="text-decoration:underline;"></span><span style="color:gray;background-color:black;"></span><span style="color:black;background-color:gray;"></span><span style="color:black;background-color:gray;font-weight:bold;">1231231.23</span>&gt;|  3:POSIXD[\d](4)
   1 &lt;<span style="text-decoration:underline;"></span><span style="color:gray;background-color:black;">1</span><span style="color:black;background-color:gray;"></span><span style="color:black;background-color:gray;font-weight:bold;">231231.23</span>&gt;|  4:CLOSE1(6)
   1 &lt;<span style="text-decoration:underline;"></span><span style="color:gray;background-color:black;">1</span><span style="color:black;background-color:gray;"></span><span style="color:black;background-color:gray;font-weight:bold;">231231.23</span>&gt;|  6:IFMATCH[0](26)
   1 &lt;<span...