WIP: parse_deparsed implementation

[jimhester]

Would address #303

I still need to do the deparsing when writing to a file, but wanted to get any comments about this end first, it seems to work well. I am not sure if missing values should return NULL or NA, thoughts?

deparse2 <- function(x) paste(collapse = "", deparse(x))
parse_deparsed(c(deparse2(head(mtcars)), deparse2(head(iris))))
#> [[1]]
#>                    mpg cyl disp  hp drat    wt  qsec vs am gear carb
#> Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
#> Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
#> Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
#> Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
#> Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
#> Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1
#> 
#> [[2]]
#>   Sepal.Length Sepal.Width Petal.Length Petal.Width Species
#> 1          5.1         3.5          1.4         0.2  setosa
#> 2          4.9         3.0          1.4         0.2  setosa
#> 3          4.7         3.2          1.3         0.2  setosa
#> 4          4.6         3.1          1.5         0.2  setosa
#> 5          5.0         3.6          1.4         0.2  setosa
#> 6          5.4         3.9          1.7         0.4  setosa

[hadley]

This should probably be a "problem" rather than terminating parsing of the whole file.

[jimhester]

Yeah agreed I wasn't exactly sure how to do that, but I see there is a warn() function to do it.

[jimhester]

Are you aware of any exported function to do deparsing?

Rf_deparse1line() is what would be best, but it doesn't look like it is part of the API :(

[hadley]

I was thinking SEXP R_Unserialize(R_inpstream_t ips) but you'd probably need to do a bit of digging to figure out what ips is supposed to be. It's probably a connection? But implementing that is probably overkill.

I just thinking evaluating code from a csv file (even if you've opted in to this) is sufficiently surprising/scary that it basically kills this idea.

[jimhester]

Ok I will table it then, we can always re-open in the future if needed.