Compiling REx "(?(?{$_ =~ |$regex (\w+ \w+)(?=\1)|})(?{s|$1||})|(?{s|$1 \w+"...
Starting first pass (sizing)
 >(?(?{$_ =~... |   1|  reg
                |    |    brnc
                |    |      piec
                |    |        atom
 >?(?{$_ =~ ... |    |          reg
 >?{$_ =~ |$... |   2|            reg
 >(?{s|$1||}... |   6|            brnc
                |    |              piec
                |    |                atom
 >?{s|$1||})... |    |                  reg
 >(?{s|$1 \w... |  12|            brnc
                |    |              piec
                |    |                atom
 >?{s|$1 \w+... |    |                  reg
Required size 16 nodes
Starting second pass (creation)
 >(?(?{$_ =~... |   1|  reg
                |    |    brnc
                |    |      piec
                |    |        atom
 >?(?{$_ =~ ... |    |          reg
 >?{$_ =~ |$... |   2|            reg
panic: top_env

C:\Temp\panic>