Passing list to `write_yaml_metadata_block()` writes an extra `-`

[cderv]

There's a fairly simple underlying bug here. Run interactively, the function inserts an extra hyphen into its output:

Input:

quarto::write_yaml_metadata_block(
     list(
         author = "John Doe",
         date = "2025-03-01"
     )
 )

Output:

[1] "---\n- author: John Doe\n  date: '2025-03-01'\n---\n"
attr(,"class")
[1] "knit_asis"
attr(,"knit_cacheable")
[1] NA

Originally posted by @CarwilB in #291

[cderv]

@CarwilB this is not a bug.

When you do the following, you are passing a list without using .list argument. So what you get is a YAML list which is expected, and start with -

quarto::write_yaml_metadata_block(
     list(
         author = "John Doe",
         date = "2025-03-01"
     )
 )  |> cat()
#> ---
#> - author: John Doe
#>   date: '2025-03-01'
#> ---

If you want to use a list for passing values, use .list=

quarto::write_yaml_metadata_block(
     .list = list(
         author = "John Doe",
         date = "2025-03-01"
     )
 )  |> cat()
#> ---
#> author: John Doe
#> date: '2025-03-01'
#> ---

^{Created on 2025-10-01 with reprex v2.1.1}

or use fields directly

quarto::write_yaml_metadata_block(
         author = "John Doe",
         date = "2025-03-01"
 )  |> cat()
#> ---
#> author: John Doe
#> date: '2025-03-01'
#> ---

[CarwilB]

Wonderful, @cderv. The behavior in the last code example is exactly what I was looking for.