feature request: return the 'final' parse patterns used for read in data (along with already returned col types)

[statsccpr]

There is already the function spec_csv() which returns the column types.

But can there also be a function that returns the set of patterns used for delimiters, comments, nas, Nulls? "meta data" that would appease the wish list in the rant here
http://www.johnmyleswhite.com/notebook/2016/09/23/no-juice-for-you-csv-format-it-just-makes-you-more-awful/

say a list containing
quote = """, escape_backslash = FALSE,
escape_double = TRUE, col_names = TRUE, col_types = NULL,
locale = default_locale(), na = c("", "NA"), quoted_na = TRUE,
comment = ""

The above 'meta data' can be taken from the default argument values say args(spec_csv)

Basically, i'm proposing read_csv(file,verbose=TRUE)
where verbose=TRUE, would output the meta data patterns along with the already output column types fromspec_csv()

I guess you could instead push this into spec_csv(,return_pattern=TRUE)

I've kind of pushed the data.table::fread guys on this too, since there seems to be others with this feature wish

Rdatatable/data.table#2437

[jimhester]

Fixed by #1172, which includes more of this metadata in the spec output, though there is still some that is not there.