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Ligo

LIGO is a functional programming language that is intended to be both user-friendly and to avoid patterns that make formal verification difficult.

LIGO offers two syntaxes:

  • JsLIGO, a sytax that is inspired by TypeScript/JavaScript
  • CameLIGO, a syntax that is inspired by OCaml

You can use either syntax and compile to Michelson to run on Tezos.

To learn LIGO, see these tutorials:

Let's define a LIGO contract in the two flavours above.

CameLIGO​

type storage = int

type parameter =
  Increment of int
| Decrement of int
| Reset

type return = operation list * storage

let main (action, store : parameter * storage) : return =
  [],
  (match action with
     Increment n -> store + n
   | Decrement n -> store - n
   | Reset       -> 0)

JsLIGO​

type storage = int;

type parameter =
  ["Increment", int]
| ["Decrement", int]
| ["Reset"];

type return_ = [list<operation>, storage];

let main = (action: parameter, store: storage) : return_ => {
  return [
    list([]),
    match(action, {
      Increment: n => store + n,
      Decrement: n => store - n,
      Reset:     ()       => 0
    })
  ];
};

This LIGO contract accepts the following LIGO expressions: Increment(n), Decrement(n) and Reset. Those serve as entrypoint identification.

Further reading​

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