dist/src/dfa.c

1629    Firstpos:  The firstpos of a node is the set of positions (nonempty leaves)
1632    * EMPTY leaves have empty firstpos.
1633    * The firstpos of a nonempty leaf is that leaf itself.
1634    * The firstpos of a QMARK, STAR, or PLUS node is the firstpos of its
1636    * The firstpos of a CAT node is the firstpos of the left argument, union
1637      the firstpos of the right if the left argument is nullable.
1638    * The firstpos of an OR node is the union of firstpos of each argument.
1658    * Every node in the firstpos of the argument of a STAR or PLUS node is in
1660    * Every node in the firstpos of the second argument of a CAT node is in
1672   int *nfirstpos;		/* Element count stack for firstpos sets. */
1673   position *firstpos;		/* Array where firstpos elements are stored. */
1702   MALLOC(firstpos, position, d->nleaves);
1703   o_firstpos = firstpos, firstpos += d->nleaves;
1725 	/* The firstpos and lastpos of the empty leaf are both empty. */
1731 	/* Every element in the firstpos of the argument is in the follow
1734 	tmp.elems = firstpos;
1751 	/* Every element in the firstpos of the second argument is in the
1754 	tmp.elems = firstpos;
1764 	/* The firstpos of a CAT node is the firstpos of the first argument,
1769 	  firstpos += nfirstpos[-1];
1793 	/* The firstpos is the union of the firstpos of each argument. */
1814 	/* This position is in its own firstpos and lastpos. */
1816 	--firstpos, --lastpos;
1817 	firstpos->index = lastpos->index = i;
1818 	firstpos->constraint = lastpos->constraint = NO_CONSTRAINT;
1831       fprintf(stderr, " firstpos:");
1834 	  fprintf(stderr, " %d:", firstpos[j].index);
1835 	  prtok(d->tokens[firstpos[j].index]);
1875   /* Get the epsilon closure of the firstpos of the regexp.  The result will
1879     insert(firstpos[i], &merged);