Create High-Level API Helpers for Struct — ffi_create

This is the main user-facing function for API mode. It generates C code to compute field offsets using the compiler, compiles it, and returns a helper object with constructor and field metadata.

Usage

ffi_create_helpers(struct_name, field_types, include_dirs = NULL)

Arguments

struct_name: Character string naming the struct (e.g., "Point2D")
field_types: Named list of FFIType objects for each field (e.g., list(x = ffi_int(), y = ffi_int()))
include_dirs: Optional character vector of include directories for compilation

Value

An rffi_struct_helpers S3 object with:

$new(): Constructor function that allocates a new struct
$fields: Named list of field metadata (offset + FFIType)
$get(ptr, field): Get field value from struct pointer
$set(ptr, field, value): Set field value in struct pointer
$lib: The compiled library object (for cleanup)

Examples

if (FALSE) { # \dontrun{
# Define struct with field types
helpers <- ffi_create_helpers(
  "Point2D",
  list(x = ffi_int(), y = ffi_int())
)

# Create instance
pt <- helpers$new()

# Set/get fields
helpers$set(pt, "x", 42L)
helpers$set(pt, "y", 100L)
helpers$get(pt, "x")  # 42L
helpers$get(pt, "y")  # 100L

# Access field metadata
helpers$fields$x$offset  # 0
helpers$fields$y$offset  # 4
} # }