- * The "internal use only" fields in regexp.h are present to pass info from
- * compile to execute that permits the execute phase to run lots faster on
- * simple cases. They are:
- *
- * regstart sv that must begin a match; NULL if none obvious
- * reganch is the match anchored (at beginning-of-line only)?
- * regmust string (pointer into program) that match must include, or NULL
- * [regmust changed to SV* for bminstr()--law]
- * regmlen length of regmust string
- * [regmlen not used currently]
- *
- * Regstart and reganch permit very fast decisions on suitable starting points
- * for a match, cutting down the work a lot. Regmust permits fast rejection
- * of lines that cannot possibly match. The regmust tests are costly enough
- * that pregcomp() supplies a regmust only if the r.e. contains something
- * potentially expensive (at present, the only such thing detected is * or +
- * at the start of the r.e., which can involve a lot of backup). Regmlen is
- * supplied because the test in pregexec() needs it and pregcomp() is computing
- * it anyway.
- * [regmust is now supplied always. The tests that use regmust have a
- * heuristic that disables the test if it usually matches.]
- *
- * [In fact, we now use regmust in many cases to locate where the search
- * starts in the string, so if regback is >= 0, the regmust search is never
- * wasted effort. The regback variable says how many characters back from
- * where regmust matched is the earliest possible start of the match.
- * For instance, /[a-z].foo/ has a regmust of 'foo' and a regback of 2.]
- */
-
-/*