Is there a way to run an expression on.exit() but only if completes normally, not on error?

Question

I\'m aware of the function on.exit in R, which is great. It runs the expression when the calling function exits, either normally or as the result of an error.

Answer 1

Just wrap the args of all your return function calls with the code that you want done. So your example becomes:

foo = function(thing){do something; return(thing)}
myfunction = function() {
     ...
     if (...) then return( foo(point 1) )
     ...
     if (...) then return( foo(point 2) )
     ...
     if (...) then return( foo(point 3) )
     ...
     return ( foo(point 4) )
}

Or just make each then clause into two statements. Using on.exit to lever some code into a number of places is going to cause spooky action-at-a-distance problems and make the baby Dijkstra cry (read Dijkstra's "GOTO considered harmful" paper).