[WIP] Module on "Writing functions" - #3
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…their own section
| In R, functions are treated as *first order citizens*, meaning they can | ||
| be assigned to variables and passed over to other functions. Let's look |
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I think I only saw the "first-order citizens" expression in programming discussions but it's really not clear to me. Is it commonly used in English?
Something like this would be clearer IMO:
| In R, functions are treated as *first order citizens*, meaning they can | |
| be assigned to variables and passed over to other functions. Let's look | |
| In R, functions are just another type of objects, meaning that they can be updated | |
| by the user, assigned to variables, and passed over to other functions. |
| ```{r} | ||
| typeof(my_variable) | ||
| typeof(TRUE) # for comparison | ||
| ``` | ||
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| This shows that `my_variable` is what's called a *closure*, which is a | ||
| special type of function. |
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IMO this adds complexity for little benefit, I'd rather remove it. If we keep this, then there should be a couple sentences about why a closure is a special type of function and it should give an example of a function that is not a closure.
| Working through the source code of functions can be very insightful, but | ||
| can quickly expose you to a lot of low-level functionality of R that | ||
| comes with a steep learning curve. As an (advanced) exercise, have a | ||
| look at the implementation of `mean` or `lapply` and try to understand |
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mean is an S3 generic so printing its source code (just UseMethod("mean")) is quite confusing (maybe that's what you wanted, I'm not sure). sd isn't generic so it's more straightforward:
| look at the implementation of `mean` or `lapply` and try to understand | |
| look at the implementation of `sd` or `lapply` and try to understand |
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| # Other ways to use and create functions | ||
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| ## Functions as arguments |
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I think this section is useful to know, but this module is about writing functions so I am not entirely convinced it fits here.
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Very early, incomplete draft.