collapse() when x has length zero

[jennybc]

It feels like collapse() would be more consistent with glue() (and more convenient) if it returned character(0) if the input has length zero.

library(glue)
glue("{x}", x = "hi")
#> hi
glue("{x}", x = character(0))
#> character(0)
collapse(x = c("hi", "bye"), last = " and ")
#> [1] "hi and bye"
collapse(x = c(NULL, "bye"), last = " and ")
#> [1] "bye"
collapse(x = c("hi", NULL), last = " and ")
#> [1] "hi"
collapse(x = NULL, last = " and ")
#> [1] ""
collapse(x = character(), last = " and ")
#> [1] ""

[jimhester]

I think this was done deliberately to mimic

paste(collapse = "", character())
#> ""

But I could be easily swayed to return character() here...

[jimhester]

It is probably a good philosophy to always return 0 length outputs for 0 length inputs, so I will change this.

[jennybc]

Yeah I was looking to glue to save me from the behaviour of paste(collapse = "", character()). Thanks.