CODEWITHSUNDEEP
haskellinputio
limp_chimp
limp_chimp

Reputation: 15173

Deleting items in stdin with haskell

I have a bit of code in my haskell program like so:

evaluate :: String -> IO ()
evaluate = ...

repl = forever $ do
  putStr "> " >> hFlush stdout
  getLine >>= evaluate

Problem is, when I press the delete key (backspace on windows), instead of deleting a character from the buffer, I get a ^? character instead. What's the canonical way of getting delete to delete a character when reading from stdin? Similarly, I'd like to be able to get the arrow keys to move a cursor around, etc.

Upvotes: 6

Views: 1975

Answers (1)

Gabriella Gonzalez
Gabriella Gonzalez

Reputation: 35089

Compile the program and then run the compiled executable. This will give the correct behavior for the Delete key. For some reason interpreting the program screws up the use of Delete.

To compile the program, just invoke ghc like this:

$ ghc -O2 myProgram.hs

This will generate a myProgram executable that you can run from the command line:

$ ./myProgram

That will then give the correct behavior for Delete.

Upvotes: 13

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