write_xpt ignores top level label attribute (but read_xpt honors it)

[bergsmat]

The specification for SAS Transport (https://support.sas.com/techsup/technote/ts140.pdf) provides that each dataset may have a label, not to be confused with column labels. haven::read_xpt() honors these where they exist, but write_xpt() does not (at least, does not react to attribute 'label' and apparently does not support alternative mechanism of supplying same). 'label' is not to be confused with 'name' which is supported (but cannot contain spaces ... consider adding that to documentation). I have not tried CRAN version 2.3.1 but there are no changes in documentation. I'd like to see data.frame 'label' written by write_xpt() to wherever read_xpt() is retrieving it.

library(SASxport) # 1.6.0
library(haven)    # 2.1.0
library(magrittr)
label(mtcars) <- 'My Cars'
mtcars %>% write.xport(file = 'SASxp.xpt') 
mtcars %>% write_xpt('haven.xpt') 
'SASxp.xpt' %>% read.xport %>% attributes %$% label # "My Cars"
'haven.xpt' %>% read.xport                          # no SAS header! (different problem)
'SASxp.xpt' %>% read_xpt   %>% attributes %$% label # "My Cars"
'haven.xpt' %>% read_xpt   %>% attributes %>% names # no label 

[hadley]

Could you please rework your reproducible example to use the reprex package ? That makes it easier to see both the input and the output, formatted in such a way that I can easily re-run in a local session.

[bergsmat]

library(SASxport)
library(haven)
library(magrittr)
label(mtcars) <- 'My Cars'
mtcars %>% write.xport(file = 'SASxp.xpt') 
mtcars %>% write_xpt('haven.xpt') 
'SASxp.xpt' %>% read.xport %>% attributes %$% label # "My Cars"
#> [1] "My Cars"
'haven.xpt' %>% read.xport                          # no SAS header! (different problem)
#> Error in read.xport(.): The specified file does not start with a SAS xport file header!
'SASxp.xpt' %>% read_xpt   %>% attributes %$% label # "My Cars"
#> [1] "My Cars"
'haven.xpt' %>% read_xpt   %>% attributes %>% names # no label 
#> [1] "names"     "row.names" "class"

^{Created on 2021-04-26 by the reprex package (v2.0.0)}

Session info

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