typed-spreadsheet provides a typed and composable API for building spreadsheets. This differs from traditional spreadsheets in a few important ways:

• you specify the relationship between inputs and outputs at compile time, not runtime, so that the relationship can be type-checked
• inputs of different types have different controls; for example, a Bool input creates a checkbox and a Double input creates a spin button
• you can only output a single value; you simulate multiple outputs by emitting a tuple of values

This project includes an example executable that you can build and tweak to test drive the library. To clone, build, and run the executable just follow these commands:

$ git clone https://github.com/Gabriel439/Haskell-Typed-Spreadsheet-Library.git
$ stack build --install-ghc             # Builds the executable
$ stack exec typed-spreadsheet-example  # Runs the executable

The executable code is short:

{-# LANGUAGE OverloadedStrings #-}

import Typed.Spreadsheet

main :: IO ()
main = textUI "Example program" logic
  where
    logic = combine <$> checkBox   "a"
                    <*> spinButton "b" 1
                    <*> spinButton "c" 0.1
                    <*> entry      "d"

    combine a b c d = display (a, b + c, d)

... and translates to a spreadsheet with all inputs on the left-hand side and the output on the right-hand side:

To learn more about the library, read the documentation on Hackage.

Mortgage calculator:

{-# LANGUAGE OverloadedStrings #-}

import Control.Applicative
import Data.Monoid
import Data.Text (Text)
import Typed.Spreadsheet

payment :: Double -> Double -> Double -> Text
payment mortgageAmount numberOfYears yearlyInterestRate
    =  "Monthly payment: $"
    <> display (mortgageAmount * (i * (1 + i) ^ n) / ((1 + i) ^ n - 1))
  where
    n = truncate (numberOfYears * 12)
    i = yearlyInterestRate / 12 / 100

logic :: Updatable Text
logic = payment <$> spinButton "Mortgage Amount"          1000
                <*> spinButton "Number of years"             1
                <*> spinButton "Yearly interest rate (%)"    0.01

main :: IO ()
main = textUI "Mortgage payment" logic

Example input and output:


Mad libs:

{-# LANGUAGE OverloadedStrings #-}

import Data.Monoid
import Typed.Spreadsheet

noun = entry "Noun"

verb = entry "Verb"

adjective = entry "Adjective"

example =
    "I want to " <> verb <> " every " <> noun <> " because they are so " <> adjective

main :: IO ()
main = textUI "Mad libs" example

Example input and output:


The easiest way to contribute is to add new controls for user input.

If you are feeling particularly adventurous, you can work on adding a diagrams output option instead of a text-based output.

The high-level API for this library is unlikely to change. I expect most of the volatility early on will be in how much configuration for controls to expose to end users. For example, controls could be generalized to permit stateful operations, but it's not clear if that additional complexity is worth it.

There might be new features added later such as diagrams output or new controls, but I expect those additions will not require any breaking changes to the API.

Copyright (c) 2014 Gabriel Gonzalez All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of Gabriel Gonzalez nor the names of other contributors may be used to endorse or promote products derived from this software without specific prior written permission.

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