On 12/05/2011 1:02 PM, Hadley Wickham wrote:
Hi all,
Is it possible to "recursively" parse srcrefs to match the recursive
structure of the underlying code? I'm interested in this because it's
I don't understand what you mean by that. It is certainly possible to
walk through nested srcrefs, to zoom in on a particular location; that's
what findLineNum() does.
the final step in allowing functions to modify other functions while
preserving the original source. I've tried to make a bit of demo of
what I want to do below, and I think I may uncovered a bug in parse.
f<- function(x = T) {
# This is a comment
if (x) return(4)
if (emergency_status()) return(T)
}
parsed_src<- parse(text = attr(f, "source"))
src_ref<- attr(parsed_src, "srcref")[[1]]
f_one<- parse(text = "{
# This is a comment
if (x) return(4)
if (emergency_status()) return(T)
}")
attr(f_one, "srcref")[[1]]
f_inside<- parse(text = "
# This is a comment
if (x) return(4)
if (emergency_status()) return(T)
")
f_inside # Displays incorrectly?
attr(f_inside, "srcref")[[1]]
# Should be:
# # This is a comment
# if (x) return(4)
That last display looks like a bug indeed. I'll take a look.
Duncan Murdoch
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