Knitr engines

Two knitr engines that enable code chunks of type extendr (individual Rust statements to be evaluated via rust_eval()) and extendrsrc (Rust functions or classes that will be exported to R via rust_source()).

Usage

eng_extendr(options)

eng_extendrsrc(options)

Arguments

options

A list of chunk options.

Value

A character string representing the engine output.

Details

Both engines support the following chunk options:

• preamble: A character vector of chunk labels. The code from those chunks is placed before the current chunk's code, in the order given, and the combined code is compiled as a single unit. Only the current chunk's code is shown in the output. This is useful for splitting Rust code across several chunks, for example defining helper functions in one chunk (typically with eval = FALSE) and calling them in another. Unlike knitr's ref.label option, which shows the reused code in the rendered document, preamble adds the code to the compile unit without displaying it. See vignette("rmarkdown", package = "rextendr") for an example.

• engine.opts: A list of arguments passed to rust_eval() (for extendr) or rust_source() (for extendrsrc), e.g. engine.opts = list(dependencies = list(rand = "0.8")). The env argument defaults to knitr::knit_global().

• eval: If FALSE, the code is displayed but not compiled.

• error: If TRUE, a compilation error is shown in the document instead of stopping the render.