Implement built-in conversions to Option and Either (e.g. toIntOption())

[abuffery]

It would be nice and hopefully easy to add some common helpers like:

Option<int> toIntOption(String x) => Option.tryCatch(() => int.parse(x));

this would allow us to have clean code like:

assert(Right("1985").map(toIntOption) == Right(Some(1985)));

[SandroMaglione]

Hi @abuffery

Do you mean generally a way to parse from one type to another using fpdart (Option)? Do you have some idea for other helpers or toIntOption would be enough?

[abuffery]

Hi @SandroMaglione

I am taking as reference Scala that has built-in conversions to Option.

In Scala you can do "41a".toInt and also "41a".toIntOption.

This leads to a leaner syntax, specially when chaining.

For example "abc".toIntOption.getOrElse(-1) is easy on the eyes to follow and read.

"5".toIntOption                 // Option[Int] = Some(5)
"abc".toIntOption               // Option[Int] = None
"abc".toIntOption.getOrElse(-1) // Int = -1

I generally find it even clearer when piped on separate lines.

"abc"
  .toIntOption
  .getOrElse(-1) // Int = -1

Other Scala conversions to Option:

• toLongOption
• toDoubleOption
• toBooleanOption
• toCharOption
• toByteOption
• toShortOption

In Dart, it would be universally useful for its most basic types:

• toBoolOption
• toDoubleOption
• toIntOption
• toStringOption

Scala does not have a toIntEither and at the same time it may make sense for common basic types.

Currently fpdart has for elaborate cases:

final tryCatch = Either.tryCatch(
  () => int.parse('invalid'),
  (e, s) => 'Error: $e',
);

Why not add to fpdart helpers for basic types when one wants returned a Left<String> instead of None

"5"
  .toIntEither("simple error message")  //  Right(5)

"Not a number"
  .toIntEither("simple error message")  //  Left("simple error message")

[SandroMaglione]

@abuffery I agree, this helpers may be indeed useful to add to fpdart, both for Option and Either.

I add this to the list of features to add to the library, using this as reference issue for further discussion if necessary 🔜

Thanks for the suggestions 👍