Hi Serge, I think what you are looking for is putStr: ghci> putStr "Test\nhere" Test here Thanks Neil On 1/12/08, Serge D. Mechveliani wrote:

People,

I have a question about usage of `show' in the GHCi dialogue system.

I introduce my user class DShow, trying to improve the class Show of Haskell-98. For example, I program

--------------------------- class DShow a where dShow :: ShowOptions -> a -> String ... main = let listOfListPairs = [ ([1,2,3], [] ), ([4,5,6], [7] ), ([9,8,0], [0,0,0]) ] :: [ ([Int], [Int]) ] opts = ShowOptions {verbosity = 2, listSepator = ", \n\n", fieldSeparator = ", \n"} in putStr (dShow opts listOfListPairs) ---------------------------

Then, the command ./Main outputs

----------------------- [([1, 2, 3], []),

([4, 5, 6], [7]),

([9, 8, 0], [0, 0, 0])] -----------------------

This way of the output format control by dShow and ShowOptions is my goal. But the command

...

main

in the ghci interpreter outputs something like this:

"[([1, 2, 3), []),\n\n([4, 5, 6), [7]),\n\n([9, 8, 0],\n\n[0, 0, 0])]"

How can the user force ghci to output the same output format as in the case of ./Main (how to interprete '\n') ?

1. If we give to the interpreter the line

...

listOfListPairs

, then the ghci dialogue system does interprete the NewLine characters on output as needed -- only for the value of (show listOfListPairs). And I need it for the value of (dShow opts listOfListPairs). Is there any way to substitute a user function instead of `show' in the ghci output? (and dShow has additional argument ...).

2. Which function outputs a string in the ghci dialogue system? Can the user make this function to interprete the NewLine character in the argument string?

Thank you in advance for your explanation.

----------------- Serge Mechveliani mechvel@botik.ru

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Hi Serge, On Sat, Jan 12, 2008 at 03:58:14PM +0300, Serge D. Mechveliani wrote:

...

main

in the ghci interpreter outputs something like this:

"[([1, 2, 3), []),\n\n([4, 5, 6), [7]),\n\n([9, 8, 0],\n\n[0, 0, 0])]"

It shouldn't do; can you give a complete example please?

1. If we give to the interpreter the line

...

listOfListPairs

, then the ghci dialogue system does interprete the NewLine characters on output as needed -- only for the value of (show listOfListPairs). And I need it for the value of (dShow opts listOfListPairs). Is there any way to substitute a user function instead of `show' in the ghci output? (and dShow has additional argument ...).

Not as far as I know. Thanks Ian