Module r_preconditions 

R-side precondition generation for type checking.

Generates stopifnot() checks in R wrapper functions that run BEFORE the .Call() boundary. This gives users clear, idiomatic R error messages with proper stack traces instead of Rust panic messages.

Each assertion checks ONE thing with a precise error message:

add <- function(a, b) {
  stopifnot(
    "'a' must be numeric, logical, or raw" = is.numeric(a) || is.logical(a) || is.raw(a),
    "'a' must have length 1" = length(a) == 1L,
    "'b' must be numeric, logical, or raw" = is.numeric(b) || is.logical(b) || is.raw(b),
    "'b' must have length 1" = length(b) == 1L
  )
  .Call(C_add, .call = match.call(), a, b)
}

Structs

FallbackParam

A parameter whose Rust type is not in the static type table.

PreconditionOutput

Output of precondition analysis for a function’s parameters.

RAssertion 🔒

A single stopifnot() assertion: "message" = condition.

Enums

RTypeCheck 🔒

Classification of an R-side type check for a function parameter.

Functions

build_precondition_checks

Build precondition checks for a function’s parameters.

extract_single_generic_arg 🔒

Extract the single generic type argument from a path segment.

is_skip_type 🔒

Returns true for types that should never get a fallback precheck.

needs_fallback 🔒

Returns true if a type is unknown to the static type table and should be recorded as a fallback parameter.

numeric_type_check 🔒

Build the R expression for the numeric type predicate.

r_check_for_reference 🔒

Map a reference type to its R-side type check.

r_check_for_type 🔒

Map a Rust type to its R-side type check, if applicable.

r_check_for_type_path 🔒

Map a syn::TypePath to its R-side type check.

r_check_for_vec_element 🔒

Map a Vec<T> or &[T] element type to the appropriate vector type check.