rlang-patterns

Tidy evaluation uses the data-masking pattern with {{ }} to forward function arguments. This allows you to dynamically reference data frame columns inside your own functions without hardcoding variable names.

The !! operator injects a single object into an expression, while !!! splices a list of objects into an expression. Both are used in rlang metaprogramming to build dynamic code patterns for data analysis.

Dynamic dots allow you to collect multiple arguments in R functions and manipulate them before evaluation. This rlang feature is essential for building flexible data-processing utilities that forward expressions or splice arguments.

Data-masking is needed when developing R packages that evaluate expressions in the context of a data frame. It allows users to refer to columns directly by name, requiring metaprogramming patterns to handle safely.

The .data and .env pronouns explicitly disambiguate between columns in a data frame and variables in the environment. Using these pronouns ensures safe data-masking and prevents scope collisions during code evaluation.