Reading a number with the incorrect decimal mark does not fail

[zsigmas]

When there is a mixture of numbers with points or commas for decimal markers, readr::read_delim (I assume this would also be the case for other reading functions) the result is unexpected. When 2.1 is parsed with a decimal marker set to "," I would expect an NA value or an error, but the number 21 or 2 is returned depending on the grouping_mark.

My intuition is that it all boils down to the readr::parse_number function.

readr::parse_number("2.1", locale = readr::locale(decimal_mark = ",", grouping_mark = "."))
# [1] 21
# Expected an NA or error, but not a number

readr::parse_number("2.1", locale = readr::locale(decimal_mark = ",", grouping_mark = ""))
# [1] 2
# Expected an NA or error, but not a number

Thanks a lot!

locale

locale:
 [1] LC_CTYPE=en_US.UTF-8          LC_NUMERIC=C                  LC_TIME=en_US.UTF-8           LC_COLLATE=en_US.UTF-8        LC_MONETARY=en_US.UTF-8       LC_MESSAGES=en_US.UTF-8       LC_PAPER=en_US.UTF-8          LC_NAME=en_US.UTF-8          
 [9] LC_ADDRESS=en_US.UTF-8        LC_TELEPHONE=en_US.UTF-8      LC_MEASUREMENT=en_US.UTF-8    LC_IDENTIFICATION=en_US.UTF-8