NEWS

OpenFst: Release 1.7
   * Removes unnecessary template parameters in constructors (1.7.5)
   * Converts RmEpsilonFstOptions from class to struct (1.7.5)
   * Eliminates redundant checks in Minimize (1.7.5)
   * CompactFst is now templated on Compactor rather than ArcCompactor (1.7.4)
   * Removes harmful constexpr specifications in the FAR extension (1.7.4)
   * Improved script API support for EncodeMapper (1.7.4)
   * New header format for the EncodeMapper (1.7.4)
   * Many cleanups to the n-gram extension (1.7.4)
   * Improved C++17 compatibility shims (1.7.4)
   * Overloads Arc constructors with default weight argument (1.7.3)
   * Fixes RmEpsilon and Union property checking bugs (1.7.3)
   * Makes Isomorphic more robust to nondeterminism (1.7.3)
   * Adds default weight argument to SetFinal (1.7.3)
   * Cleans up low-level logging (1.7.3)
   * Adds power-weight mappers (1.7.3)
   * Adds expander cache (1.7.3)
   * Fixes bug with coinaccessible states in NaturalAStarEstimate (1.7.2)
   * Optionally allows building with Bazel (1.7.2)
   * Simplifies string printing interface (1.7.2)
   * Marks weight converters const (1.7.2)
   * Adds NoMatchComposeFilter (1.7.2)
   * Removed static assertions that trigger bugs in GCC (1.7.1)
   * Evaluates many weight operations at compile-time (1.7.1)
   * Improved use of move semantics, especially in cache-backed FSTs (1.7.0)
   * Adds configure-time test for float equality reflexivity (1.7.0)
   * Removes volatile qualifiers from float weights (1.7.0)
   * Protections for signedness in string compiler (1.7.0)
   * Adds additional overloads to Equals (1.7.0)
   * Clean-up to weight constructors (1.7.0)

OpenFst: Release 1.6
   * Optimized label lookup in SymbolTable (1.6.9)
   * Fixed HashMatcher issues with SetState() and Find() consistency (1.6.8)
   * Fixed PROGRAM_FLAGS documentation string in binaries (1.6.8)
   * Fixed handling of symbol tables in EpsNormalize (1.6.8)
   * Fixed error reporting when FST arc type unknown (1.6.8)
   * The `first_path` option to ShortestPath is now optimal for A* (1.6.7)
   * Renames SymbolTable::kNoSymbol to kNoSymbol (1.6.7)
   * Exposes PowerMapper to the scripting API (1.6.7)
   * Fixes linking of the special SOs (1.6.7)
   * Adds kShortestDelta for operations dependent on shortest-distance (1.6.6)
   * Adds Python methods for (un)pickling and (de)serializing FSTs (1.6.6)
   * Adds constructive variants of Invert and Project (1.6.6)
   * Increases code sharing in MemoryPool/MemoryArena (1.6.6)
   * Improves consistency of matcher FST ownership (1.6.6)
   * Fixes error handling in HashMatcher (1.6.6)
   * Adds non-trivial A* estimator class (1.6.6)
   * Prevents unreachable code generation in libfstscript (1.6.5)
   * Adds move constructors for non-trivial weight types (1.6.5)
   * Standardizes method names for tuple weight types (1.6.5)
   * Eliminates undefined behavior in weight hashing (1.6.5)
   * Optimizes binary search in SortedMatcher (1.6.5)
   * Adds SetWeight (1.6.5)
   * Fixes typing error in Python FAR reader (1.6.4)
   * Removes restriction that Prune argument have commutative weights (1.6.3)
   * Improves configuration of CompositeWeight readers and writers (1.6.3)
   * Improves accuracy of ShortestDistance summation (1.6.3)
   * SetFinal now "moves" its weight argument (1.6.3)
   * Exposes ArcIterator and EncodeMapper flags in Python (1.6.3)
   * Properly sets return codes in FST binaries (1.6.3)
   * Eliminates StringWeight macros (1.6.3)
   * Finalizes most virtual method overrides (1.6.2)
   * Adds float format support to FST drawing (1.6.1)
   * Fixes missing includes of <fst/log.h> (1.6.1)
   * Adds the "special" extension and the fstspecial binary; this is similar to
     fstconvert but accepts arguments for specifying special labels (phi, rho,
     and sigma) of FSTs (1.6.0)
   * Exposes allow_negative_label option for Python symbol tables (1.6.0)
   * Many classes and constants moved into an internal namespace (1.6.0)
   * Extensive modernization for C++11 style (1.6.0)
   * Adds Member method to SymbolTable (1.6.0)
   * Adds HashMatcher (1.6.0)

OpenFst: Release 1.5
   * Generalized epsilon normalization to non-functional case (1.5.0)
   * Added multiple pushdown transducer (MPDT) support (1.5.0)
   * Added general gallic (plus is union) semiring (1.5.0)
   * Added p-subsequential determinization (1.5.0)
   * Fixed missing Isomorphic components (1.5.0)
   * Added FST compression extension (1.5.0)
   * Added final method to matchers (1.5.0)
   * Fixed various compiler issues (1.5.0)
   * Fixed Isomorphic function (1.5.0)
   * Added Python extension (1.5.0)
   * Added UnionWeight (1.5.0)
   * Added missing const qualification to (1.5.1):
      - SymbolTableIterator access
      - EncodeMapper writing to file
      - EncodeMapper SymbolTable access
   * Added TrivialComposeFilter for more efficient composition when one
     of the arguments is epsilon-free (1.5.1)
   * Added InputEpsilonMapper and OutputEpsilonMapper arc mappers (1.5.1)
   * Added properties bits kUnweightedCycles and kWeightedCycles (1.5.1)
   * Replaced internal custom reference-counting (RefCounter) with C++11 smart
     pointers where possible, and fixed reference-counting bugs (1.5.1)
   * When calling DeleteStates on a MutableFst with a shared impl, the impl
     is set to a new empty impl rather than copying and deleting (1.5.1)
   * Prepended `Pdt` to the Expand libraries and classes in the PDT
     extension, and prepended `MPdt` to the Expand libraries and classes
     in the MPDT extension, so that both can be used in the same compilation
     unit (1.5.1)
   * Added option to PDT Replace for compiling a strongly-regular RTN into a
     bounded-stack PDT (1.5.1)
   * Improved symbol table support for PDT Replace, including automatic
     generation of parentheses symbols (1.5.1)
   * Improvements to scripting API (1.5.1):
      - Added methods for FST access and mutation
      - Added additional checks for arc/weight compatibility
      - WeightClass::One and WeightClass::Zero now require a specified weight
        type at time of construction
      - Improved VectorFstClass constructors
      - Added linear-time check for cyclic dependencies in Replace
      - Added EncodeMapperClass, a template-free box for an EncodeMapper
   * Improvements to the binaries (1.5.1):
      - Fixed no-op --precision flag to fstdraw (1.5.1)
      - Fixed no-op --file_list_input flag to farcreate (1.5.1)
   * Improvements to the Python extension (1.5.1):
      - Adds methods for creating an empty mutable FST
      - Adds methods for FST access via state and arc iteration
      - Adds FST compilation from arclists (cf. fstcompile)
      - Adds FST printing and drawing
      - Adds FarReader and FarWriter classes.
   * Consolidated Python extension into single module (1.5.2)
   * FarReader's GetFst method now returns a pointer (1.5.2)
   * Python add_arc now takes an Arc object (1.5.2)
   * Fixed build flags for dlopen (1.5.2)
   * Fixed FSTERROR macro (1.5.2)
   * Scripting API and Python weight objects now support semiring arithmetic
     (1.5.3)
   * Mutation methods of the Python Fst object now support chaining (1.5.3)
   * Adds optional minimization of non-deterministic FSTs (1.5.3)
   * Adds check for error when opening files when compiling strings into FARs
     (1.5.4)
   * Prevents underflow when using LogProbArcSelector in random generation
     (1.5.4)
   * Adds routines for parsing string flags to the scripting API (1.5.4)
   * Makes random weight generators a single template class (1.5.4)
   * Makes weight Properties constexpr where possible (1.5.4)
   * Adds RemoveSymbol method to SymbolTable (1.5.4)

OpenFst: Release 1.4
   * Port to C++11 (1.4.0)
   * Isomorphic function added (1.4.0)
   * Disambiguate function added (1.4.0)
   * Matcher interface augmented with Priority method
   * Special matchers (rho/sigma/phi) can match special symbols
     on both input FSTs in composition/intersection provided at each
     state pair they only match one side (1.4.0)
   * Added ExplicitMatcher to suppress implicit matches (e.g. epsilon
     self-loops) (1.4.0)
   * Linear{Tagger,Classifier}Fst extensions added (1.4.0).
   * Generalized state-reachable to work when input is cyclic (so long as no
     final state is in a cycle). This ensures label-reachable (and hence label
     lookahead) works with cyclic input (1.4.0)
   * Added Condense to build the condensation graph (SCCs condensed to single
     states) of an FST (1.4.0).
   * Added an option to Reverse to specify whether a super-initial state
     should always be created (1.4.0).
   * Fixed bugs in FirstCacheStore, PowerWeight, and StringCompiler (1.4.0).
   * Changed SymbolTable to use faster data structure (1.4.0).
   * Added 'min' disambiguation in determinizaton to keep only the minimum
     output in a non-functional transducer when plus=min/max
     (flag --disambiguate_output) (1.4.1)
   * Compiler issues in linear-fst fixed (1.4.1)

OpenFst: Release 1.3
   * Support for non-fatal exits on errors: (1.3.1)
      - Added FLAGS_fst_error_fatal: FST errors are
        fatal if true (default); o.w. return objects flagged as bad:
        e.g., FSTs - kError
        prop. true, FST weights - not a Member().
      - Added kError property bit signifying bad FST
      - Added  NoWeight() method to FST weight requirements that returns
        weight that is not a Member().
   * Various improvements to the FAR extensions (1.3.1)
      - a single FST is now a FAR type
      - FLAGS_initial_symbols: Uses the symbol table from the
        first FST in the archive for all entries"
      - Input/output to standard input/output for some FAR and arc types
   * --with-icu configuration option no longer needed (1.3.1)
   * Improved flags usage esp. if use SET_FLAGS not SetFlags/InitFst (1.3.2)
   * Added 'fst' as possible far writer type (1.3.2)
   * phi matcher can now accept 0 as the phi label (1.3.2)
   * Added ngram-fst extension (1.3.2)
   * Improved performance of PDT composition (1.3.3)
   * Memory-map support (1.3.3)
   * Fixed cross-FST serialization issues (1.3.3)
   * Fixed NGramFst off-by-one issue (1.3.3)
   * farextract now allows one to specify a list of comma-separated keys,
     including key ranges (1.3.3)
   * Fixed bug in PDT replace that could cause close paren IDs to collide
     with open paren IDs (1.3.4)

OpenFst: Release 1.2
   * Added lookahead matching and filtering for faster composition
   * Added EditFst for mutation of o.w. immutable FSTs
   * Added script sub-namespace defining type FstClass, a non-templated
     Fst<Arc> to hold the arc template type internally. This and FST
     operations on it allow easier I/O and scripting at the cost of some
     runtime dispatching.
   * Added per-arc-iterator control of Fst caching.
   * Added PowerWeight and Power Arc.
   * Added SparsePowerWeight and SparsePowerArc (1.2.4)
   * Added SignedLogWeight and SignedLogArc (1.2.4)
   * Added ExpectationWeight and ExpectationArc (1.2.4)
   * Added AStarQueue, PruneQueue and NaturalPruneQueue disciplines (1.2.6)
   * Added Log64Weight and Log64Arc to FST library throughout, including 
     support throughout scripts/bins/dsos (1.2.8)
   * Added delayed RandGenFst that outputs tree of paths weighted
     by count (1.2.8)
   * Added fstsymbols shell-level command
   * Added total weight removal option to pushing
   * Changed methods for symbol table mutation:
     use MutableInputSymbols()/MutableOutputSymbols().
   * Numerous efficiency improvements esp in composition, replace, and caching
   * Made "fstmap" handle semiring conversion by adding "to_std", "to_log"
     and "to_log64" as supported 'map_type' arguments (1.2.8).
   * Made the destructive implementation of RmEpsilon skip over states
     admitting no non-epsilon incoming transition (1.2.8).
   * Fixed numerous bugs (1.2 through 1.2.9) including:
      - improper types of some approximation deltas
      - sub-optimal hashing functions
      - issues in internal reuse of shortest distance
      - hashing bug in FloatWeight
      - bug in shortest path queue
      - symbol table checksumming issues
      - various C++ standards issues
      - Visit() behavior when visitation aborted
      - Decode() hash performance bug (1.2.1)
      - EditFst::Copy(bool) method when the boolean parameter is true (1.2.7)
      - SymbolTable memory leak in Invert() (1.2.8)
      - Added escaping of " and \ in labels in fstdraw, needed for dot to
        function properly (1.2.8)
      - Fixed handling of final weight of start state in fstpush (1.2.8)
      - Added FST_LL_FORMAT to fix 64-bit integer printf issues (1.2.9)
      - Fixed missing <functional> includes (1.2.9)
      - Fixed reused local variable names (1.2.9)
      - Fixed passing string by reference in FstDraw args (1.2.9)
   * Added extensions directories including:
      - finite-state archive (FAR) utilities,
        added stlist format supporting writing/reading to/from standard out/in
        at the library-level (1.2.8)
      - compact FSTs
      - lookahead FSTs
      - pushdown transducers (improved in 1.2.1 through 1.2.7).
   * Added StateMap/StateMapFst; renamed Map/MapFst to ArcMap/ArcMapFst;
     map/MapFst retained (but deprecated) (1.2.9)
   * Deleted ArcSum() and ArcMerge; use StateMap w/ ArcSumMapper and
     ArcUniqueMapper (1.2.9).
   * Incremented version of ConstFst/CompactFsts to stop memory alignment
     that fails on pipes. Made old version raises errors when read on
     pipes (1.2.9).
   * Improved determinize hash (1.2.9)
   * Removed stdio uses (1.2.10)
   * Fixed library ordering issues esp. with newer GNU build tools (1.2.10)

OpenFst: Release 1.1
   * Added compat.h to src/include/fst to fix missing defines
   * Fixed bug in acyclic minimization that led to non-minimal
     (but equivalent) results
   * Fixed missing FST typedef in various matchers in matcher.h
     so that they can be cascaded
   * Opened file streams binary where appropriate

OpenFst: Release 1.0 (Additions to beta version):
   * Matcher class added for matching labels at FST states. Includes
     special matchers for sigma (any), rho ('rest'), and phi ('fail')
     labels.
   * Composition generalized with arbitrary filters, matchers, and state
     tables.
   * Sequence and matching composition filters provided. (see compose.h,
     compose-filter.h, matcher.h, state-table.h)
   * Unique n-best (see shortest-path.h)
   * Pruning in determinization and epsilon removal (see determinize.h,
     rmepsilon.h)
   * New Fst class:
      - Compact FSTs for space-efficient representation (see compact-fst.h)
   * New Weight classes:
      - MinMax
      - Lexicographic
   * Miscellaneous bug fixes