The higher-level loops preserve an additional state between ite
+rations:
       whether the last match was zero-length.  To break the loop, the
       following match after a zero-length match is prohibited to have
+ a
       length of zero.  This prohibition interacts with backtracking (
+see
       "Backtracking"), and so the second best match is chosen if the 
+best
       match is of zero length.
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