decode_column.md
In artoo: Lossless CDISC-Native Input and Output for Clinical Datasets

decode_column chains two hops when from and to codelists share no values

Code
  decode_column(cdisc_dm, spec, "DM", from = "SEX", to = "SEXN", direction = "to_code")
Condition
  Error:
  ! Values in `SEX` are not in codelist "SEXN".
  x Unmatched: "F" and "M".
  i Set `no_match = "keep"` or `"na"` to allow them.

decode_column validates its inputs loudly

Code
  decode_column(cdisc_dm, spec, "DM", from = "USUBJID", to = "USUBJ2")
Condition
  Error:
  ! Neither "USUBJ2" nor "USUBJID" references a codelist in dataset "DM".
  i Add a codelist_id to one of them in the spec.