Dynamic-branching slice that compiles Rust once

A drop-in replacement for the targets targets::tar_target() pattern helper slice(), for use unquoted in the pattern argument of a tarpolyglot constructor. Like tarpolyglot_map(), on tar_target_rs() it compiles the extendr crate once in a companion <name>_rust_lib target and reuses it across the selected branches; on tar_target_py() / tar_target_jl() it is exactly slice(). See tarpolyglot_map() for the full explanation and the compile-once mechanics.

Usage

tarpolyglot_slice(..., index)

Arguments

...

Upstream target(s) to branch over, with the same meaning as in the targets slice() pattern.

index

Integer vector of branch indices to keep, as in the targets slice() pattern.

Value

This function is a marker consumed by the tarpolyglot constructors and is not meant to be evaluated on its own; calling it directly raises an error.

See also

tarpolyglot_map(), tar_target_rs(), tar_target_py(), tar_target_jl()

Examples

if (FALSE) { # \dontrun{
tarpolyglot::tar_target_rs(
  name = rs_some, script = "square.rs", inputs = c(x = "vals"),
  post_script = "post.R", pattern = tarpolyglot_slice(vals, index = c(1, 3))
)
} # }