Returning anonymous functions from lapply – what is going wrong?

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R passes promises, not the values themselves. The promise is forced when it is first evaluated, not when it is passed, and by that time the index has changed if one uses the code in the question. The code can be written as follows to force the promise at the time the outer anonymous function is called and to make it clear to the reader:

pl <- lapply(1:3, function(y) { force(y); function(x) pow(x,y) } )

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