See https://histogrammar.github.io/histogrammar-docs for a complete introduction to Histogrammar.

This is a Scala implementation for Scala versions 2.10, 2.11, 2.12 and 2.13.

Latest Scala release: v1.0.30 (Dec 2023).

With Spark 3.X, based on Scala 2.12 or 2.13, make sure to pick up the correct histogrammar jar file:

spark = SparkSession.builder.config("spark.jars.packages", "io.github.histogrammar:histogrammar_2.12:1.0.30,io.github.histogrammar:histogrammar-sparksql_2.12:1.0.30").getOrCreate()

For Scala 2.13, in the string above simply replace "2.12" with "2.13".

December, 2023

Histogrammar has a standard Maven POM. With Maven 3+, run

mvn install -P scala-2.XX

in the base directory (to compile everything) or one of the subdirectories, where XX selects the scala version (2.10, 2.11, 2.12, 2.13). All subdirectories depend on core, so this must be installed first.

The Scala implementation is verified against the Python implementation by running exactly the same tests on both. They agree numerically to one part in a trillion, with the same NaN/infinity handling, and exchange the same JSON.

All primitives except UntypedLabel preserve type information in the Scala REPL, so you can extract values or tab-complete without casting.

In the future, JIT-compilation will be available, similar to the ROOT/Cling interface in Python, but compiling to Java bytecode with Janino instead of native bytecode with LLVM.