Parse functions supplied by user — mk_userdef_fn

This function takes a data.table containing user-supplied function definitions and parses them into a structured format. The input data.table is expected to have specific columns that include the function type, the function itself, the name of the function, and a unique hash for the function. The output is a list of data.table objects, where each data.table corresponds to a unique function type and contains detailed information about each function, including a character representation and the callable function itself.

Usage

mk_userdef_fn_dt(x, env = parent.frame())

Arguments

x

A data.table object representing the endpoint definition data model, which should contain the following columns:

fn_type: Character vector specifying the type of function.
fn: List of callables (length 1) representing the function to be called.
fn_name: Character vector with the name of the function.
fn_hash: Character vector with a unique hash for each function.

env

The environment from which to evaluate the functions. The default is the parent frame from which the function is called.

Value

A data.table with each row containing a parsed function definition. The columns include:

fn_type: Character vector with the type of function.
fn_hash: Character vector with the unique hash of the function.
fn_name: Character vector with the name of the function.
fn_call_char: Character vector with the function call as a string.
fn_callable: List of callables representing the parsed function.

Examples

library(data.table)

# Create function table with user-defined functions
# (typically from endpoint definitions via unnest_endpoint_functions)
endpoint_fns <- data.table(
  endpoint_spec_id = c(1, 1, 2, 2),
  fn_type = c("data_prepare", "stat_by_strata_by_trt",
              "data_prepare", "stat_by_strata_by_trt"),
  fn = list(
    quote(function(study_metadata) NULL),
    quote(function(dat, ...) nrow(dat)),
    quote(function(study_metadata) NULL),
    quote(function(dat, ...) nrow(dat))
  ),
  fn_name = c("prep_fn", "n_subj", "prep_fn", "n_subj"),
  fn_hash = c("hash1", "hash2", "hash1", "hash2")
)

# Parse functions into callable format
fn_table <- mk_userdef_fn_dt(endpoint_fns)

# Result: unique functions by hash, deduplicated
nrow(fn_table)  # 2 (hash1, hash2)
#> [1] 2
fn_table[, .(fn_type, fn_name)]
#>                  fn_type fn_name
#>                   <char>  <char>
#> 1:          data_prepare prep_fn
#> 2: stat_by_strata_by_trt  n_subj

# fn_callable column contains executable functions
fn_table$fn_callable[[1]]  # Callable function
#> function (study_metadata) 
#> NULL
#> <environment: 0x55b1d7404770>