This function takes a character vector of paths and returns just the file
name, by default without the extension. A TextReuseCorpus uses
the paths to the files in the corpus as the names of the list. This function
is intended to turn those paths into more manageable identifiers.
Examples
paths <- c("corpus/one.txt", "corpus/two.md", "corpus/three.text")
filenames(paths)
#> [1] "one" "two" "three"
filenames(paths, extension = TRUE)
#> [1] "one.txt" "two.md" "three.text"