## Changed
- string_metric.normalized_levenshtein supports now all weights
- when different weights are used for Insertion and Deletion the strings can not be swapped inside the Levenshtein implementation anymore. So different weights for Insertion and Deletion are now supported.
- replace C++ implementation with a Cython implementation. This has the following advantages:
- The implementation is less error prone, since a lot of the complex things are done by Cython
- slighly faster than the current implementation (up to 10% for some parts)
- about 33% smaller binary size
- reduced compile time
- Added **kwargs argument to process.extract/extractOne/extract_iter that is passed to the scorer
- Add max argument to hamming distance
- Add support for whole Unicode range to utils.default_process
## Performance
- replaced Wagner Fischer usage in the normal Levenshtein distance with a bitparallel implementation
- all normalized string_metrics can now be used as scorer for process.extract/extractOne
- Implementation of the C++ Wrapper completely refactored to make it easier to add more scorers, processors and string matching algorithms in the future.
- increased test coverage, that already helped to fix some bugs and help to prevent regressions in the future
- improved docstrings of functions
- Added bitparallel implementation of the Levenshtein distance for the weights (1,1,1) and (1,1,2).
- Added specialized implementation of the Levenshtein distance for cases with a small maximum edit distance, that is even faster, than the bitparallel implementation.
- Improved performance of `fuzz.partial_ratio`
-> Since `fuzz.ratio` and `fuzz.partial_ratio` are used in most scorers, this improves the overall performance.
- Improved performance of `process.extract` and `process.extractOne`
- the `rapidfuzz.levenshtein` module is now deprecated and will be removed in v2.0.0
These functions are now placed in `rapidfuzz.string_metric`. `distance`, `normalized_distance`, `weighted_distance` and `weighted_normalized_distance` are combined into `levenshtein` and `normalized_levenshtein`.
- added normalized version of the hamming distance in `string_metric.normalized_hamming`
- process.extract_iter as a generator, that yields the similarity of all elements, that have a similarity >= score_cutoff
- multiple bugs in extractOne when used with a scorer, thats not from RapidFuzz
- fixed bug in `token_ratio`
- fixed bug in result normalisation causing zero division
- When using score_cutoff there is now a guarantee that it returns 0 when result < score_cutoff
- each function has now a preprocess argument to specify whether strings should be preprocessed
- the default preprocessing does now lower case and trim
- extract and extractOne accept a custom processor method instead of utils.default_processor now
- QRatio was removed since it does now exactly the same as normal ratio
Max Bachmann