CODEWITHSUNDEEP
rnamespacesr-environmentr-glue
Dan Chaltiel
Dan Chaltiel

Reputation: 8494

Better way to deal with namespace when using glue::glue

I want to create a function that itself uses the awesome glue::glue function.

However, I came to find myself dealing with some namespace issue when I want to glue a variable that exists in both function and global environments:

x=1

my_glue <- function(x, ...) {
    glue::glue(x, ...)
}
my_glue("foobar x={x}") #not the expected output
# foobar x=foobar x={x}

I'd rather keep the variable named x for package consistency.

I ended up doing something like this, which works pretty well so far but only postpone the problem (a lot, but still):

my_glue2 <- function(x, ...) {
    x___=x; rm(x)
    glue::glue(x___, ...)
}
my_glue2("foobar x={x}") #problem is gone!
# foobar x=1
my_glue2("foobar x={x___}") #very unlikely but still...
# foobar x=foobar x={x___}

Is there a better/cleaner way to do this?

Upvotes: 0

Views: 202

Answers (1)

Ronak Shah
Ronak Shah

Reputation: 388982

Since the value x = 1 is nowhere passed to the function, in the current scenario a way to do this would be to evaluate the string in the global environment itself where the value of x is present before passing it to the function. 

my_glue(glue::glue("foobar x={x}"))
#foobar x=1

my_glue(glue::glue("foobar x={x}"), " More text")
#foobar x=1 More text

Another option (and I think this is the answer that you are looking for) is to get the value of x from the parent environment. glue has .envir parameter, where the environment to evaluate the expression can be defined. 

my_glue <- function(x, ...) {
   glue::glue(x, ...,.envir = parent.frame())
}
my_glue("foobar x={x}")
#foobar x=1

Upvotes: 2

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