Records are like tuples but with named parameters. In other words, they hold a set of key/data pairs. To instantiate a record, you must first declare its type as follows :
type user = {
id : nat,
is_admin : bool,
name : string
};
And here is how to define an associated record value :
let alice : user = {
id : 1n,
is_admin : true,
name : "Alice"
};
Access
You can access the whole record or get one key in particular by using the . operator:
let alice_admin : bool = alice.is_admin;
Update
The syntax for the functional updates of record in ReasonLIGO follows that of ReasonML. You can modify values in a record as follows :
let change_name = ( u : user) : user =>{ ...u, name : "Mark" };
⚠️ Note that user has not been changed by the function. Rather, the function returned a nameless new version of it with the modified name.
⚠️ Notice the operator … that destructures the record u into a nameless set of (key, value) pairs
Nested updates
A unique feature of LIGO is the ability to perform nested updates on records.
For example if you have the following record structure:
type color =
Blue
| Green;
type preferences = {
color : color,
other : int
}
type account = {
id : int,
preferences : preferences
}You can update the nested record with the following code:
let change_color_preference = (account : account, color : color): account =>
{ ...account, preferences.color: color };
Your mission
1- Refactor the type of coordinates as a record instead of a tuple. Name the parameters x, y and z.
2- Refactor earth_coordinates with the record type.
2- Refactor the modified_earth_coordinates constant as a record (copy of earth_coordinates) with its third component changed to 5.