Created
June 10, 2015 19:39
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An R Function that Only Works When You Try to Debug it
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| # Debugging in R is much better than many languages, but sometime it can be | |
| # frustrating. Here's a function that makes it even more frustrating -- | |
| # it only works when you try to debug it! | |
| # The challenge: | |
| ### Write a function that, if the function has a browser in it, will execute | |
| ### every line correctly, but if it does not have a browser in it, it will | |
| ### error. | |
| # The solution: | |
| hate <- function() { | |
| if (length(grep("browser()", body(hate))) == 1) { | |
| stop("I hate you.") | |
| } | |
| "I returned fine." | |
| } | |
| # If you run it without a browser... | |
| hate() | |
| # Error in hate() : I hate you. | |
| # ...But then add the browser. | |
| hate <- function() { | |
| browser() | |
| if (length(grep("browser()", body(hate))) == 1) { | |
| stop("I hate you.") | |
| } | |
| "I returned fine." | |
| } | |
| > hate() | |
| # Called from: hate() | |
| # Browse[1]> | |
| # debug at #3: if (length(grep("browser()", body(hate))) == 1) { | |
| # stop("I hate you.") | |
| # } | |
| # Browse[2]> | |
| # debug at #6: [1] "I returned fine." | |
| # Browse[2]> | |
| # [1] "I returned fine." |
body(hate) <- bquote({ getFunction("browser")(); .(body(hate)) })
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