Version 2 is the first version of music21 since v.1 to make substantial changes in the code base that introduce backwards incompatibilities in order to make going forward faster and smoother. It doesn't change anything super fundamental à la Python 3's print function, so most code should still run fine, but definitely test in a separate environment before upgrading on any code you have that needs to run without problems. The system is still changing and more backward-incompatible changes could be included until v.2.1.
We have had 420 commits since the last release, so there is a lot that is new!
Substantial changes include:
- Offsets and quarterLengths are now stored internally as Fractions if they cannot be exactly represented as floating point numbers. A lot of work went into making this conversion extremely fast; you probably won't ever notice the speed difference, but you can now be sure that seven septuplets will add up to exactly a half note. For instance:
- >>> n = note.Note()>>> n.duration.appendTuplet(duration.Tuplet(3,2))>>> n.fullName'C in octave 4 Quarter Triplet (2/3 QL) Note'>>> n.quarterLengthFraction(2, 3)>>> n.quarterLengthFloat # if you need it...0.6666666666666666
- Converter structure has been overhauled for more easily adding new converters in the future. If you've wanted to write a converter or already have one for a format not supported but have been daunted by how to include it in music21 now is a great time to do it. Speaking of which...
- MEI format is supported for import (thanks to Chris Antila and the ELVIS team at McGill university for this great enhancement)
- Python 2.6 is no longer supported. All tests and demos pass and run on Python 2.7, 3.3, and 3.4. (3.2 and older are not supported)
- FreezeThaw on Streams works much better and caching loaded scores works great (some of this was included in 1.9, so definitely upgrade at least to that.
- Lots of places that used to return anonymous tuples, now return namedtuples for more easily understanding what the return values mean.
- Integrated Travis-CI testing and Coverage tests will keep many more bugs out of music21 in the future.
- Many small problems with Sorting and stream handling fixed.
- Corpus changed: for various licensing reasons, v.2.0 does not include the scores from the MuseData corpus anymore. This change mostly affects Haydn string quartets and Handel's Messiah. However, new replacement scores are being included and 2.1 will have as many great works as before. The MuseData scores are still available online. MuseData is now a deprecated format and no further testing on it will be conducted; only bug fixes that are easily implemented will be accepted.
- music21 is now available under the BSD license in addition to LGPL!
We will try to stick to something close to the semantic versioning model in the future once v.2.1 is released. In other words, after 2.1, we'll try very hard not to break anything that worked in v.2.1 until v. 3.0 is released. This will probably mean that the version numbers are going to creep up faster in the future.
Still todo before v.2.1 is a major change in how elements are stored in Streams. Stay tuned if you care about performance tweaks etc., otherwise ignore it -- we'll keep the interface the same so you might not notice anything except speed improvements.
Smaller backward-incompatible changes include:
- Stream __repr__ now includes a pointer rather than a number if .id is not set. This change will make filtering out doctests easier in the future.
- TinyNotation no longer allows for a two-element tuple where the second element is the time signature. Replace: ("C4 D E", "3/4") with ("tinynotation: 3/4 C4 D E")
- Obscure calls in SpannerBundle have been removed: spannerBundle.getByClassComplete etc.
- Convenience classes: WholeNote, HalfNote, etc. have been removed. Replace with Note(type='whole') etc.
- Old convenience classes for moving from Perl to Python (DefaultHash, defList) have been removed or renamed (defaultlist)
- Articulations are marked as equal if they are of the same class, regardless of other attributes.
- common.almostLessThan, etc. are gone; were only needed for float rounding, and that problem is fixed.
- duration.aggregateTupletRatio is now aggregateTupletMultiplier, which is more correct.
- scala.ScalaStorage renamed scala.ScalaData
- common.nearestMultiplier now returns the signed difference.
- layout -- names changed for consistency (some layout objects had "startMeasure" and some "measureStart" - now they're all the same); now all use namedtuples.
- rarely used functions in Sites, base, Duration, SpannerStorage, VariantStorage, have been removed or renamed. I'd be surprised if these affect anyone outside the development team.
Improvements and bug fixes:
- common.mixedNumeral for working with large rational numbers
- common.opFrac() optionally converts a float, int, or Fraction to a float, int, or Fraction depending on what is necessary to get exact representations. This is a highly optimized function responsible for music21 working with Fractions at about 10x the speed of normal Fraction work.
- Rest objects get a .lineShift attribute for layout.
- staffDetails, printObject MXL had a bug, writing out "True" instead of "yes"
- staffLines is now an int not float. (duh!)
- better checks for reused pointers.
- lots of private methods are now ready for public hacking!
- Lyric.rawText() will return "hel-" instead of "hel" for "hel-lo".