str_interp() formatting of interpolated list depends on presence other interpolated expressions

[amhrasmussen]

Using str_interp() it seems that interpolated list are outputted differently depending on the presence of additional interpolated expressions.

This pull request makes behavior independent of additional interpolations.

Before:

a_list <- c("item1", "item2", "item3")
other <- "fruit"
stringr::str_interp("here is a list of 3 items: ${a_list}")
[1] "here is a list of 3 items: item1"
stringr::str_interp("here is the list again: ${a_list}, and another ${other}")
[1] "here is the list again: c("item1", "item2", "item3"), and another fruit"

After:

stringr::str_interp("here is a list of 3 items: ${a_list}")
[1] "here is a list of 3 items: c("item1", "item2", "item3")"
stringr::str_interp("here is the list again: ${a_list}, and another ${other}")
[1] "here is the list again: c("item1", "item2", "item3"), and another fruit"

[smbache]

Looks good to me. Thanks!

[hadley]

Can you please add a bullet to NEWS? It should briefly describe the change (starting with name of the function), and crediting yourself with (@yourname, #issuenumber).

[amhrasmussen]

@hadley I've added a bullet to NEWS.md. No issue has been created for this, so I've left that out.

[hadley]

Thanks!