Haskell scanf

A lightweight library for one-off parsing and printing.

scanf [fmt|%d lazy %s and %d strict %s|]
      "3 lazy functions and 2 strict fields"
  = Just (3 :+ "functions" :+ 2 :+ "fields" :+ ())

Quasiquotes are optional. Format strings can also be defined with pure Haskell combinators.

printf (fmt_ (int . " lazy " % string . " and " % int . " strict " % string)
       (8 :+ "dogs" :+ 9 :+ "cats" :+ ())
  = "8 lazy dogs and 9 strict cats"

With quasiquotes, the following conversion strings are supported:

• %d : signed integer (Int)
• %l : signed integer (Integer, unbounded)
• %f : floating point (Double)
• %s : string of non-space characters (String)
• %[...]: Scanset (String)
• %c : single character (Char)
• %% : parse/print a literal percent character

N.B.: in scanf, spaces in the format string match any number of whitespace character until the next nonspace character.

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Though it also offers a printf function, scanf is thus named as there are only few other preexisting Haskell implementations, whereas many Haskell printf libraries can already be found on Hackage.

Similar to:

• xformat (scanf and printf)
• fmt (printf)
• formatting (printf)