Static branching unnames list columns in .data grid

[shirdekel]

Prework

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Description

I want to pass named lists to targets through the .data grid, but something seems to unname them.

Reproducible example

library(drake)
library(tibble)

arg <- 
  list(
    list(A = "a"),
    list(B = "b")
  )

# Retains list names

drake_plan(
  x = target(
    arg,
    transform = map(
      arg = !!arg,
      .id = FALSE
    )
  )
)
#> # A tibble: 2 x 2
#>   target command      
#>   <chr>  <expr_lst>   
#> 1 x      list(A = "a")
#> 2 x_2    list(B = "b")

my_grid <- 
  tibble(
    arg = arg
  )

# Removes list names

drake_plan(
  x = target(
    arg,
    transform = map(
      .data = !!my_grid,
      .id = FALSE
    )
  )
)
#> # A tibble: 2 x 2
#>   target command   
#>   <chr>  <expr_lst>
#> 1 x      list("a") 
#> 2 x_2    list("b")

^{Created on 2020-09-22 by the reprex package (v0.3.0)}

Session info

devtools::session_info()
#> ─ Session info ───────────────────────────────────────────────────────────────
#>  setting  value                       
#>  version  R version 4.0.2 (2020-06-22)
#>  os       macOS Mojave 10.14.6        
#>  system   x86_64, darwin17.0          
#>  ui       X11                         
#>  language (EN)                        
#>  collate  en_AU.UTF-8                 
#>  ctype    en_AU.UTF-8                 
#>  tz       Australia/Sydney            
#>  date     2020-09-22                  
#> 
#> ─ Packages ───────────────────────────────────────────────────────────────────
#>  package     * version date       lib source        
#>  assertthat    0.2.1   2019-03-21 [1] CRAN (R 4.0.0)
#>  backports     1.1.9   2020-08-24 [1] CRAN (R 4.0.2)
#>  base64url     1.4     2018-05-14 [1] CRAN (R 4.0.0)
#>  callr         3.4.4   2020-09-07 [1] CRAN (R 4.0.2)
#>  cli           2.0.2   2020-02-28 [1] CRAN (R 4.0.0)
#>  crayon        1.3.4   2017-09-16 [1] CRAN (R 4.0.0)
#>  desc          1.2.0   2018-05-01 [1] CRAN (R 4.0.0)
#>  devtools      2.3.0   2020-04-10 [1] CRAN (R 4.0.0)
#>  digest        0.6.25  2020-02-23 [1] CRAN (R 4.0.0)
#>  drake       * 7.12.2  2020-06-02 [1] CRAN (R 4.0.0)
#>  ellipsis      0.3.1   2020-05-15 [1] CRAN (R 4.0.0)
#>  evaluate      0.14    2019-05-28 [1] CRAN (R 4.0.0)
#>  fansi         0.4.1   2020-01-08 [1] CRAN (R 4.0.0)
#>  filelock      1.0.2   2018-10-05 [1] CRAN (R 4.0.0)
#>  fs            1.5.0   2020-07-31 [1] CRAN (R 4.0.2)
#>  glue          1.4.2   2020-08-27 [1] CRAN (R 4.0.2)
#>  highr         0.8     2019-03-20 [1] CRAN (R 4.0.0)
#>  hms           0.5.3   2020-01-08 [1] CRAN (R 4.0.0)
#>  htmltools     0.5.0   2020-06-16 [1] CRAN (R 4.0.0)
#>  igraph        1.2.5   2020-03-19 [1] CRAN (R 4.0.0)
#>  knitr         1.29    2020-06-23 [1] CRAN (R 4.0.2)
#>  lifecycle     0.2.0   2020-03-06 [1] CRAN (R 4.0.0)
#>  magrittr      1.5     2014-11-22 [1] CRAN (R 4.0.0)
#>  memoise       1.1.0   2017-04-21 [1] CRAN (R 4.0.0)
#>  pillar        1.4.6   2020-07-10 [1] CRAN (R 4.0.1)
#>  pkgbuild      1.1.0   2020-07-13 [1] CRAN (R 4.0.2)
#>  pkgconfig     2.0.3   2019-09-22 [1] CRAN (R 4.0.0)
#>  pkgload       1.1.0   2020-05-29 [1] CRAN (R 4.0.0)
#>  prettyunits   1.1.1   2020-01-24 [1] CRAN (R 4.0.0)
#>  processx      3.4.4   2020-09-03 [1] CRAN (R 4.0.2)
#>  progress      1.2.2   2019-05-16 [1] CRAN (R 4.0.0)
#>  ps            1.3.4   2020-08-11 [1] CRAN (R 4.0.2)
#>  R6            2.4.1   2019-11-12 [1] CRAN (R 4.0.0)
#>  remotes       2.1.1   2020-02-15 [1] CRAN (R 4.0.0)
#>  rlang         0.4.7   2020-07-09 [1] CRAN (R 4.0.1)
#>  rmarkdown     2.3     2020-06-18 [1] CRAN (R 4.0.0)
#>  rprojroot     1.3-2   2018-01-03 [1] CRAN (R 4.0.0)
#>  sessioninfo   1.1.1   2018-11-05 [1] CRAN (R 4.0.0)
#>  storr         1.2.1   2018-10-18 [1] CRAN (R 4.0.0)
#>  stringi       1.5.3   2020-09-09 [1] CRAN (R 4.0.2)
#>  stringr       1.4.0   2019-02-10 [1] CRAN (R 4.0.0)
#>  testthat      2.3.2   2020-03-02 [1] CRAN (R 4.0.0)
#>  tibble      * 3.0.3   2020-07-10 [1] CRAN (R 4.0.1)
#>  txtq          0.2.0   2019-10-15 [1] CRAN (R 4.0.0)
#>  usethis       1.6.1   2020-04-29 [1] CRAN (R 4.0.0)
#>  utf8          1.1.4   2018-05-24 [1] CRAN (R 4.0.0)
#>  vctrs         0.3.4   2020-08-29 [1] CRAN (R 4.0.2)
#>  withr         2.2.0   2020-04-20 [1] CRAN (R 4.0.0)
#>  xfun          0.17    2020-09-09 [1] CRAN (R 4.0.2)
#>  yaml          2.2.1   2020-02-01 [1] CRAN (R 4.0.0)
#> 
#> [1] /Library/Frameworks/R.framework/Versions/4.0/Resources/library

Desired result

The .data grid retaining list element names.

[wlandau]

Names should stick in 9fb42f5. But whether you use the CRAN version or the dev version, it's recommended in this case to use language objects than lists.

library(drake)
library(tibble)

grid <- tibble(
  arg = list(
    quote(list(A = "a")),
    quote(list(B = "b"))
  )
)

drake_plan(
  x = target(
    arg,
    transform = map(
      .data = !!grid,
      .id = FALSE
    )
  )
)
#> # A tibble: 2 x 2
#>   target command      
#>   <chr>  <expr_lst>   
#> 1 x      list(A = "a")
#> 2 x_2    list(B = "b")

^{Created on 2020-09-22 by the reprex package (v0.3.0)}

[shirdekel]

Thanks for the quick fix! Can you explain the benefit of quoting/using language objects?

[wlandau]

drake_plan() creates code, and static branching inserts symbols to help automate that code generation. So your first example was really trying to bootstrap back the code that generated the list objects in arg. It’s usually better to begin with code or basic types to avoid having to reconstruct the code that generated the object.