Introduce a Rational Type

[fallen-icarus]

Idea

Add the Rational type to the standard library. The Rational type is a good way of representing decimals on-chain. Use cases:

1. Specifying the asking prices for atomic swaps.
2. Specifying the interest rates for p2p loans.
3. Specifying required collateral ratios for p2p loans.

Current Alternative

The current alternative is to implement the Rational type yourself. This has the following issues:

1. Not all aiken users may know how to properly implement the Rational type for themselves.
2. Developers can implement Rational in slightly different ways which can cause unexpected behaviors when using another developer's version.

It would be better if there was a single standard implementation we all used.

[rvcas]

Cool idea, do you already have some idea on how to define this and what functions should go along with it?

[fallen-icarus]

PlutusTx has Rational defined in the module PlutusTx.Ratio (I can't link to it because I built the documentation locally with nix). My thinking was for aiken to just copy its implementation and functions. It's a fairly small module.

[rvcas]

yea ok, we can do that probably, we'll look into it. Thanks for the idea.

[MicroProofs]

Rational Type is currently in the std lib 😄