On 5/28/25 04:15, Pavel Krivitsky via R-devel wrote:
Dear All,
Perhaps this should go in r-package-devel, but I suspect that this is
going to turn into a feature request, and I want to run it by the list
before filing it in the Bugzilla.
I would like to specify a long string literal without making the line
of code too long. In R,
"abc
def"
yields the string "abc\def", and, as far as I can tell, there is no
mechanism for preventing it from inserting a newline into the string.
Putting a backslash before the newline, i.e.,
"abc\
def"
eliminates the newline in (that I know of) C/C++, Python, and Julia,
but it makes no difference in R.
The implicit concatenation of Python and C/C++, e.g., "abc" "def", is a
syntax error as well in R.
It is, of course, possible to use paste0(), but is there a more concise
built-in mechanism in R of which I am not aware?
If not, I think it would make sense to bring R in line with the others.
Currently, backslash and no backslash before a newline behave
identically (at least as far as I can tell), so I doubt that a
nontrivial amount of code relies on the current behaviour. [1]
What would be real example of a long string literal you would want to
enter this way?
For entering a long text with newlines, one can use raw strings in R
(see ?Quotes) - but there you would see the newlines and indentation.
I've seen code where "paste0" has been aliased to a local function
named with a single letter to make concatenation more concise.
Best
Tomas
Any thoughts?
Pavel
[1] On the off chance that it does, it should easy to check by
searching for "\\\n" in package sources, because a backslash before a
newline is a syntax error outside a string.