Expressions

Expression blocks are semicolon separated list of expression. The last expression define the type of the whole expression.

e1; e2

The semicolon let the developer to ignore the result of an expression, but it is only possible for unit expression; the following expression will fail to compile:

12 + 15; // ignored int expression
13

Depending of where you declare an expression, the scope will change; for instance inside an entrypoint expression you can access the contract fields.

You can bind a name to an expression using let syntax:

let a = 12;
a

Which can be written also as:

let a = 12 in a

Let is also useful for tuple destructuring:

const a: (int, nat) = (12, 13n);
const b: int = let (x, y) = a in x;