Creating NFT from NFA
#526
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Please let me know before merge, this will break noodler. |
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We will wait with merging this until everything which needs to be done for Noodler is done to not introduce breaking changes in the middle of merging those PRs. If there is an urgent need to merge this, let me know. |
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You can merge. |
| @@ -108,7 +108,23 @@ Nft parse_from_mata(const std::filesystem::path& nft_file); | |||
| * @param epsilons Which symbols handle as epsilons. | |||
| * @return NFT representing @p nfa_state with @p num_of_levels number of levels. | |||
| */ | |||
| Nft create_from_nfa(const nfa::Nfa& nfa_state, size_t num_of_levels = DEFAULT_NUM_OF_LEVELS, std::optional<Symbol> next_levels_symbol = {}, const std::set<Symbol>& epsilons = { EPSILON }); | |||
| Nft from_nfa_with_levels_zero(const nfa::Nfa& nfa_state, size_t num_of_levels = DEFAULT_NUM_OF_LEVELS, bool explicit_transitions = true, std::optional<Symbol> next_levels_symbol = {}); | |||
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The decsription of this function was not updated.
| const State marker_state{ dft_marker.add_state() }; | ||
| dft_marker.levels.resize(marker_state + 1); | ||
| dft_marker.levels[marker_state] = 1; | ||
| SymbolPost& symbol_post{ *state_post.find(move.symbol) }; | ||
| SymbolPost& symbol_post{ *dft_marker.delta.mutable_state_post(source).find(move.symbol) }; |
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Sometimes, because of creating a new state on line 282, the delta can reallocate, causing the state_post to point to memory that is no longer used, causing a SEGFAULT. Because of this, we need to get a fresh mutable_state_post again.
| @@ -392,7 +391,7 @@ Nft ReluctantReplace::reluctant_leftmost_nft(nfa::Nfa nfa, Alphabet* alphabet, S | |||
| const Word& replacement, ReplaceMode replace_mode) { | |||
| nfa = reluctant_nfa_with_marker(std::move(nfa), begin_marker, alphabet); | |||
| Nft nft_reluctant_leftmost{ | |||
| nft::builder::create_from_nfa(nfa, 2, { EPSILON }, { EPSILON }) }; | |||
| nft::builder::from_nfa_with_levels_zero(nfa, 2, true, { EPSILON }) }; | |||
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Yes, it is.
Originally, the call was intended to create an NFT with 2 levels, where the epsilon transition symbol was EPSILON, and EPSILON (last parameter) was assigned to the new edges introduced between levels.
Now, the true parameter indicates that we want explicit transitions (no jump transitions except for epsilon transitions across all levels). The epsilon symbol is implicitly defined as EPSILON, and the EPSILON
parameter, as before, ensures that newly introduced edges are labeled with EPSILON.
This PR:
builder::create_from_nfatobuilder::from_nfa_zero_levels.nfa::from_nfa_leveledtobuilder::from_nfa_increasing_levels.from_nfa_increasing_levels(previouslyfrom_nfa_leveled) from thenfanamespace tobuilder.from_nfa_zero_levels, and closesmata::nft::builder::create_from_nfaon nfa without transitions #491. This may also resolve issue Replace transducer construction from NFAs #506.ReluctantReplace::marker_nft, where adding a new state to the automaton caused invalidation of a reference to a mutable state post, leading to a SEGFAULT.