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rmetaprogrammingnon-standard-evaluation

in R, how do I quote a comment using quote or bquote?

quote(# this is a comment)

How can I do something like the above?

Solution

  • quote() captures the original code in its wholeSrcref attribute, which preserves comments:

    x <- quote({
    ## This is a comment
})

src <- attributes(x)$wholeSrcref          # <--- preserves the comment

    However, this returns an object of class srcref, not a true expression that can be passed to eval(). Depending on what you are trying to do, you may find these functions for manipulating srcref objects useful. For example,

    as.character(src)[2]
[1] "    ## This is a comment"