R: Development notes - 'dots.R'

dev-notes-dots {rlang} | R Documentation

## Development notes - `dots.R`

### Description

Development notes - `dots.R`

### `.__error_call__.` flag in dots collectors

Dots collectors like `dots_list()` are a little tricky because they may error out in different situations. Do we want to forward the context, i.e. set the call flag to the calling environment? Collectors throw errors in these cases:

1. While checking their own parameters, in which case the relevant context is the collector itself and we don't forward.

2. While collecting the dots, during evaluation of the supplied arguments. In this case forwarding or not is irrelevant because expressions in `...` are evaluated in their own environment which is not connected to the collector's context.

3. While collecting the dots, during argument constraints checks such as determined by the `.homonyms` argument. In this case we want to forward the context because the caller of the dots collector is the one who determines the constraints for its users.

[Package rlang version 1.0.2 Index]