chmatch validate nomatch argument

[jangorecki]

Docs states that nomatch is coerced to integer.
When providing integer of length 0L it should warn/error/handle other way. Currently output is not really useful.

library(data.table)
chmatch(c("a","b"), c("a","c"), nomatch = integer())
#[1]        1 45133224

[MichaelChirico]

base::match returns NA (no warning):

match(c("a","b"), c("a","c"), nomatch = integer())
# [1]  1 NA

Looks like it's just wrapping in asInteger in C:

...
int nomatch = asInteger(CADDR(args));
...