Partial Functions

Partial functions are functions that will not always return an output for every input. An example is integer division:

  • x / 1 produces an output: x
  • x / 0 cannot produce an output but will throw an error.

This folder is a summary of the article: Keep your Types Small and Your Bugs Smaller

There are three different ways one can handle partial functions in Purescript:

  1. Crash on invalid inputs
    • via Partial
  2. Return an error-container type:
    • via Maybe a
    • via Either String a
    • via Either CustomErrorType a
    • via Veither errorRows a
  3. Use refined types
    • via NonZeroInt (or some other refined type)
  4. Return the output on valid inputs and a default value on invalid inputs

Compilation Instruction

Start the REPL, import the file's module, and pass in different arguments to the function to see what happens

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