Register a validation rule

Adds a rule to the validation engine. A rule is a function fn(x, ctx) that inspects a krt_tbl and returns a list of issues (each created with the internal issue helper); the engine attaches the rule id, layer, standard, and resolved severity.

Usage

register_validator(
  rule_id,
  fn,
  layer = c("structural", "semantic"),
  severity = c("error", "warning", "note", "info"),
  applies = function(x) TRUE,
  standard = NA_character_,
  replace = FALSE
)

Arguments

rule_id

A unique rule identifier, e.g. "struct-missing-name".

fn

The rule function function(x, ctx) returning a list of issues.

layer

Either "structural" or "semantic".

severity

Default severity: one of "error", "warning", "note", "info".

applies

A predicate function(x); the rule runs only when it returns TRUE (used by conditional rule packs).

standard

Optional reporting standard the rule enforces (e.g. "cell-line-auth-minimum").

replace

Overwrite an existing rule with the same rule_id? Defaults to FALSE, so a plugin cannot silently replace a built-in rule; pass TRUE to deliberately override one.

Value

Invisibly NULL; called for its side effect.

Examples

# A rule inspects the table and returns a list of issues. This demonstration
# rule reports nothing, so registering it leaves validation results unchanged.
demo_rule <- function(x, ctx) list()
register_validator("demo-no-op", demo_rule, layer = "semantic",
                   severity = "note", replace = TRUE)
"demo-no-op" %in% list_validators()$rule_id
#> [1] TRUE
validate_krt(krt_example)$valid
#> [1] TRUE