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haskellpartial-application

Is there a way to partially apply getLine?

Is there a way to partially apply getLine to writeFile or a similar function (for file naming purposes)? I want to do something like this:

main = writeFile ??? . computeSomething =<< somethingElse

??? should be a line entered by the user to name the output file but I have no idea what to insert for ???. I tried inserting =<< getLine and similar snippets but nothing worked for me.

Is it possible to achieve this without using do-notation in a readable way?

Solution

  • You can use flip to flip the order of arguments:

    getLine >>= flip writeFile computeSomething

    The tool pointfree is helpful if you want to eta-reduce a function.