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3 points by rocketnia 1104 days ago | link | parent

I've seen this before. What's happening, somehow, is that every time you write more than one line in a definition at the REPL in a Windows prompt, a capital R is being inserted at each newline. Arc compiles this to the Racket code _R, and when Racket executes this, it can't find the _R variable.

I seem to remember I used work around this by always pasting my multi-line definitions from a text editor rather than writing them directly at the REPL.

3 points by jsgrahamus 1103 days ago | link

Thanks for mentioning this. Saw it in a racket repl, too. Reported it to the Racket Users list.


3 points by jsgrahamus 1104 days ago | link

BTW, this is Windows 7x64.

I am pasting the definition into the arc cmd window.


2 points by rocketnia 1103 days ago | link

Oh, sorry. Now that I test it, I realize I remembered incorrectly.

The only time I get those spurious R characters is when I paste code into the REPL and then press enter manually. I don't get them when typing multi-line definitions directly at the REPL, and I don't get them if the code I'm pasting already has a line break at the end.

So the habit I've formed is to make sure the code I'm pasting already has a line break at the end.

I notice this issue also happens on Racket 5.3.3 -- I'm a few versions behind -- and it does not happen in the REPLs for Node.js or Clojure. It's some kind of bug in Racket. (Hmm... Racket's port.c has a bunch of spaghetti code for CRLF processing. Maybe the bug's in there somewhere.)


1 point by akkartik 1104 days ago | link

Oh I wonder if it's a linefeed-newline thing. I know "\r" is the code for linefeed, for example..