A few years since the last release in late 2020, the RcppTOML package is now back with a new and shiny CRAN release 0.2.0. It is now based on the wonderful toml++ C++17 library by Mark Gillard and gets us (at long last!) full TOML v1.0.0 compliance for use with R.
TOML is a file format that is most suitable for configurations, as it is meant to be edited by humans but read by computers. It emphasizes strong readability for humans while at the same time supporting strong typing as well as immediate and clear error reports. On small typos you get parse errors, rather than silently corrupted garbage. Much preferable to any and all of XML, JSON or YAML – though sadly these may be too ubiquitous now. TOML is frequently being used with the projects such as the Hugo static blog compiler, or the Cargo system of Crates (aka “packages”) for the Rust language.
This package is a rewrite of the internals interfacing the library, and updates the package to using toml++ and C++17. The R interface is unchanged, and a full run of reverse dependencies passed. This involved finding one sole test failure which turned to have been driven by a non-conforming TOML input file which Jianfeng Li kindly fixed at the source making his (extensive) set of tests in package configr pass too. The actual rewrite was mostly done in a one-off repo RcppTomlPlusPlus which can now be considered frozen.
The short summary of changes follows.
Changes in version 0.2.0 (2023-01-10)
Rewritten in C++17 using toml++ for TOML v1.0.0 compliance
Unchanged interface from R, unchanged (and expanded tests)
Several small continuous integration upgrades since last release
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