R 4.1.0 anonymous functions are not treated correctly

[notPlancha]

I'm writing a Sweave document and when knitting my document, my anonymous functions are turned into bigger anonymous functions; for example:

<<>>=
(\(x) x^2)(4)
@

Turns into

(function(x){x^2})(4)

In the output. My issue is that I'm doing a bunch of these, and it's occupying a lot of space in my output, which I didn't wish it did.
Explicitly,

Turns into

I know this is because of tidy=TRUE and formatR, but I did not find any parameter that changes this behaviors. Adding the option tidy=FALSE resolves the issue, but I think this is not intended, so I'm writing an issue about it.
Interestingly, not putting the brackets produces a code that should not run, since the function requires brackets to run afaik.

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[yihui]

The core technical issue is that R's parser turns \() into function() internally:

> deparse((parse(text='(\\(x) x^2)(4)'))[[1]])
[1] "(function(x) x^2)(4)"

but I think I can come up with a hack to preserve \() in formatR. Thanks for the report!

[yihui]

Should be fixed now. You can install the development version via

remotes::install_github('yihui/formatR')