Build Structured Data Frame Subtypes R package schmear version 0.1.0 Provides developer-focused helper functions and S3 classes to ease the creation of structured subtypes of data frames. Developers can require certain columns and types to be present, and can enforce crossing and nesting relationships between values in different columns. Type-specific metadata and attributes are preserved through common data frame manipulations. Software Imports: rlang, cli, vctrs Suggests: dplyr, pillar, testthat (>= 3.0.0) Cory McCartan <mccartan@psu.edu> Comprehensive R Archive Network (CRAN) Cory McCartan [aut, cre, cph] (ORCID: <https://orcid.org/0000-0002-6251-669X>) MIT + file LICENSE (https://CRAN.R-project.org/package=schmear/LICENSE) 2026-05-29 application/tgz https://CRAN.R-project.org/package=schmear doi:10.32614/CRAN.package.schmear