Expand a prepared person-time Parquet dataset into the sequential target-trial layout and write the result to output_path.

This is a thin FFI shim. All dtype-exact, deterministic Polars work lives in the tte_expand core crate (which is #![forbid(unsafe_code)]). The binding crate cannot forbid unsafe because the extendr macros emit the FFI registrar. Every tte_expand::ExpandError is mapped to an R error condition.

Usage

expand_parquet(
  input_path,
  output_path,
  id_col,
  period_col,
  treatment_col,
  eligible_col,
  outcome_col,
  first_period,
  last_period,
  estimand
)

Arguments

input_path

Path to the input Parquet file.

output_path

Path where the expanded Parquet is written.

id_col, period_col, treatment_col

Column names in the input.

eligible_col, outcome_col

Eligibility / outcome column names (TrialEmulation defaults are "eligible" / "outcome").

first_period, last_period

Inclusive integer bounds on trial_period.

estimand

"ITT" (no artificial censoring) or "PP" (per-protocol, censor each trial at the first treatment deviation). Case-insensitive.

Value

NULL, invisibly; the expansion is written to output_path. Errors in the core engine surface as R errors.

Examples

if (FALSE) { # \dontrun{
expand_parquet(
  "input.parquet", "expanded.parquet",
  "id", "period", "treatment", "eligible", "outcome",
  0L, .Machine$integer.max, "ITT"
)
} # }