list0() improvements

[jmbarbone]

library(fuj)

lst <- function(...) {
  e <- as.list(substitute(list(...)))[-1L]
  lapply(e[!vapply(e, identical, NA, substitute(), USE.NAMES = FALSE)], eval)
}

# list0() doesn't do well with a few edge bases
try(list0())
#> Warning in seq_len(i - off): first element used of 'length.out' argument
#> Error in seq_len(i - off) : 
#>   argument must be coercible to non-negative integer
try(list0(b = , ))
#> Error in names(out) <- names(mc)[-1L][seq_len(i - off)] : 
#>   'names' attribute [1] must be the same length as the vector [0]
try(list0(a = 1, , ))
#> Error in names(out) <- names(mc)[-1L][seq_len(i - off)] : 
#>   'names' attribute [2] must be the same length as the vector [1]

# newer implementation doesn't have these issues
lst()
#> list()
lst(b = , )
#> named list()
lst(a = 1, , )
#> $a
#> [1] 1

# and it's faster
foo <- "hello"
bench::mark(
  list0 = list0(a = 1, b = 2, , 3, foo, list),
  lst = lst(a = 1, b = 2, , 3, foo, list, b = , )
)
#> # A tibble: 2 × 6
#>   expression      min   median `itr/sec` mem_alloc `gc/sec`
#>   <bch:expr> <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl>
#> 1 list0         270µs    299µs     2439.        0B     2.07
#> 2 lst           124µs    130µs     6912.        0B     4.12

^{Created on 2024-02-15 with reprex v2.1.0}