Random notes about tagging R source code with Universal Ctags

Manual group:Universal Ctags
Manual section:7


ctags … --languages=+R …
ctags … --language-force=R …
ctags … --map-Python=+.r …


This man page gathers random notes about tagging R source code with Universal Ctags.


If a variable gets a value returned from a well-known constructor and the variable appears for the first time in the current input file, the R parser makes a tag for the variable and attaches a kind associated with the constructor to the tag regardless of whether the variable appears in the top-level context or a function.

Well-known constructor and kind mapping

Constructor kind
function() function
c() vector
list() list
data.frame() dataframe

If a variable doesn’t get a value returned from one of well-known constructors, the R parser attaches globalVar or functionVar kind to the tag for the variable depending on the context.

Here is an example demonstrating the usage of the kinds:


G <- 1
v <- c(1, 2)
l <- list(3, 4)
d <- data.frame(n = v)
f <- function(a) {
        g <- function (b) a + b
        w <- c(1, 2)
        m <- list (3, 4)
        e <- data.frame(n = w)
        L <- 2

“output.tags” with “--options=NONE --sort=no --fields=+KZ -o - input.r”

G       input.r /^G <- 1$/;"    globalVar
v       input.r /^v <- c(1, 2)$/;"      vector
l       input.r /^l <- list(3, 4)$/;"   list
d       input.r /^d <- data.frame(n = v)$/;"    dataframe
n       input.r /^d <- data.frame(n = v)$/;"    nameattr        scope:dataframe:d
f       input.r /^f <- function(a) {$/;"        function
g       input.r /^      g <- function (b) a + b$/;"     function        scope:function:f
w       input.r /^      w <- c(1, 2)$/;"        vector  scope:function:f
m       input.r /^      m <- list (3, 4)$/;"    list    scope:function:f
e       input.r /^      e <- data.frame(n = w)$/;"      dataframe       scope:function:f
n       input.r /^      e <- data.frame(n = w)$/;"      nameattr        scope:dataframe:f.e
L       input.r /^      L <- 2$/;"      functionVar     scope:function:f