Changes in version 2022.0 (2025-09-28)                 

Update to version 9.0, the 2022 CODATA recommended values. Package
versioning has been aligned with the CODATA versioning scheme.

                 Changes in version 1.0.1 (2021-02-25)                  

  - Fix compatibility with units 0.7-0.

                 Changes in version 1.0.0 (2020-11-11)                  

Update to version 8.1, the 2018 CODATA recommended values (#7 addressing
#6). This version contains some breaking changes that are necessary to
streamline future updates and provide a stable symbol table:

  - The codata table includes the absolute uncertainty instead of the
    relative one. Thus, the rel_uncertainty column has been dropped in
    favour of the new uncertainty. Also, columns have been slightly
    reordered.
  - Symbol names for constants have changed. The old ones were
    hand-crafted and thus unmanageable. This release adopts the ASCII
    symbols defined by NIST in their webpage, except for those that
    collide with some base R function. In particular, there are two
    cases: c, the speed of light, has been renamed as c0; sigma, the
    Stefan-Boltzmann constant, has been renamed as sigma0.
  - Constant types, or categories, (column codata$type) adopts the names
    defined by NIST in the webpage too. Some constants belong to more
    than one category (separated by comma); some others belong to no
    category (missing type).

There are some new features too:

  - In addition to the codata data frame, this release includes
    codata.cor, a correlation matrix for all the constants.
  - In addition to syms_with_errors and syms_with_units, there is a new
    list of symbols called syms_with_quantities (available if the
    optional quantities package is installed), which provides constant
    values with uncertainty and units.
  - Experimental support for correlated values in syms_with_errors and
    syms_with_quantities is provided (disabled by default; see details
    in help(syms) for activation instructions).

                 Changes in version 0.0.2 (2018-01-08)                  

  - Use units::as_units() instead of the deprecated units::parse_unit()
    (#1).
  - Install the speed of light as a unit (#2).
  - Unitless constants now show a 1 instead of unitless as unit (#3).
  - Unit Ω has been replaced by ohm (#4).