[R] gsub regexp question

[ALBERTO VIEIRA FERREIRA MONTEIRO]

I just found a curious behaviour of regexp and I'd like to share with y'all.

gsub("^([[:alnum:]\\[\\]]*).*", "\\1", "array[n] <- 10", perl=T) #
works as expected ("array[n]")

gsub("^([[:alnum:]\\[\\]]*).*", "\\1", "array[n] <- 10", perl=F) #
doesn't work ("a")

I didn't find anything in the documentation explain what's going on,
and why the second gsub doesn't work.

Alberto Monteiro