Hi Tatsuo,
Here are six incremental patches on top of v43.
nocfbot-0001 through nocfbot-0004 are the same patches from the
previous round (32-bit test fix, PREV/NEXT restriction, ALT lexical
ordering, reluctant quantifiers).
nocfbot-0005: Detect zero-consumption NFA cycles
Adds a per-element visited bitmap to detect zero-consumption cycles
during DFS epsilon expansion. Before each state's DFS, the bitmap
is cleared; as nfa_advance_state() recurses through epsilon
transitions, each elemIdx is marked visited. If the same elemIdx
is reached again within the same DFS, it means an epsilon-only
loop -- the state is freed immediately.
The ad-hoc (count == 0 && min == 0) exit condition in
nfa_advance_end() is removed. The FIXME test cases are resolved
and renamed to "Zero-Consumption Cycle Detection".
nocfbot-0006: Allow A{0} quantifier
With cycle detection in place, this becomes straightforward.
Lowers the {n} bound minimum from 1 to 0. A{0} is treated as an
epsilon transition -- the variable is skipped entirely.
Next I plan to work on test reorganization, cross-database result
comparison, and a review pass over the NFA executor.
Best regards,
Henson
