Preserve caption of <gt_tbl> object when generating LaTeX code with gt::as_latex()

[ami-null]

Prework

• Read and abide by gt's code of conduct and contributing guidelines.
• Search for duplicates among the existing issues (both open and closed).

Proposal

gt::as_latex() drops the caption in the gt_tbl object:

dt <- mtcars[1:2, 1:2]
gt::gt(data = dt, caption = "mtcars data") |> 
    gt::as_latex() |> 
    as.character()
#> [1] "\\begin{longtable}{rr}\n\\toprule\nmpg & cyl \\\\ \n\\midrule\\addlinespace[2.5pt]\n21 & 6 \\\\ \n21 & 6 \\\\ \n\\bottomrule\n\\end{longtable}\n"

gt::gt(data = dt) |> 
    gt::tab_caption("mtcars data") |> 
    gt::as_latex() |> 
    as.character()
#> [1] "\\begin{longtable}{rr}\n\\toprule\nmpg & cyl \\\\ \n\\midrule\\addlinespace[2.5pt]\n21 & 6 \\\\ \n21 & 6 \\\\ \n\\bottomrule\n\\end{longtable}\n"

As can be seen in the output, there is no \caption{} command in the LaTeX code that is generated. This is an issue because my workflow is saving the generated LaTeX code string to a file and then calling \input{} on that file in LaTeX, and then I end up getting a table with no captions. This also prevents cross-referencing tables in PDF documents generated using Rmarkdown or Quarto.

Interestingly enough, when the title and subtitle in gt::tab_header() are retained, but through an un-numbered \caption*{} in the LaTeX code:

gt::gt(data = dt) |> 
    gt::tab_header(
        title = gt::md("tab_header title"),
        subtitle = gt::md("tab_header subtitle")
    ) |> 
    gt::as_latex() |> 
    as.character()
#> [1] "\\begin{longtable}{rr}\n\\caption*{\n{\\large tab\\_header title} \\\\ \n{\\small tab\\_header subtitle}\n} \\\\ \n\\toprule\nmpg & cyl \\\\ \n\\midrule\\addlinespace[2.5pt]\n21 & 6 \\\\ \n21 & 6 \\\\ \n\\bottomrule\n\\end{longtable}\n"

I understand that this a possible duplicate of #818. But, I am opening this one seeing that #818 is almost 3 years old.

sessionInfo()
#> R version 4.3.3 (2024-02-29 ucrt)
#> Platform: x86_64-w64-mingw32/x64 (64-bit)
#> Running under: Windows 10 x64 (build 19045)
#> 
#> Matrix products: default
#> 
#> 
#> locale:
#> [1] LC_COLLATE=English_United States.utf8 
#> [2] LC_CTYPE=English_United States.utf8   
#> [3] LC_MONETARY=English_United States.utf8
#> [4] LC_NUMERIC=C                          
#> [5] LC_TIME=English_United States.utf8    
#> 
#> time zone: 
#> tzcode source: internal
#> 
#> attached base packages:
#> [1] stats     graphics  grDevices utils     datasets  methods   base     
#> 
#> loaded via a namespace (and not attached):
#>  [1] vctrs_0.6.5       cli_3.6.2         gt_0.10.1         knitr_1.45       
#>  [5] rlang_1.1.3       xfun_0.42         purrr_1.0.2       styler_1.10.2    
#>  [9] generics_0.1.3    glue_1.7.0        markdown_1.12     htmltools_0.5.7  
#> [13] fansi_1.0.6       rmarkdown_2.26    R.cache_0.16.0    tibble_3.2.1     
#> [17] evaluate_0.23     fastmap_1.1.1     yaml_2.3.8        lifecycle_1.0.4  
#> [21] compiler_4.3.3    dplyr_1.1.4       fs_1.6.3          pkgconfig_2.0.3  
#> [25] rstudioapi_0.15.0 R.oo_1.26.0       R.utils_2.12.3    digest_0.6.34    
#> [29] R6_2.5.1          tidyselect_1.2.0  utf8_1.2.4        reprex_2.1.0     
#> [33] pillar_1.9.0      commonmark_1.9.1  magrittr_2.0.3    R.methodsS3_1.8.2
#> [37] tools_4.3.3       withr_3.0.0       xml2_1.3.6

^{Created on 2024-03-20 with reprex v2.1.0}