Changes in version 0.1-0 (2026-04-09)                  

Initial release — clean-room implementation of ISO 6976:2016 for CRAN.

Scope

Implements all properties and uncertainties defined in ISO 6976:2016:

  - Compression factor Z (§5, Eq. 1)
  - Molar mass M (Eq. 5)
  - Ideal-gas and real-gas gross and net calorific values on molar,
    mass, and volumetric bases (Eqs. 2–12)
  - Ideal-gas and real-gas density and relative density (Eqs. 13–19)
  - Ideal-gas and real-gas gross and net Wobbe indices
    (Eqs. 15–16, 20–21)
  - Standard uncertainties of all properties (Annex B, Eqs. B.4–B.14)

Design decisions

  - Single Rcpp back-end (iso6976_calc) computes all properties in one
    call.
  - GasComponents R6 class provides named component access without
    normalization (normalization is outside the scope of ISO 6976:2016).
  - Component names are in English following ISO 6976:2016 Table A.2.
  - Reference data sets example1, example2, example3, example3_ex are
    the worked examples from ISO 6976:2016 Annex D.