Mutable let bindings in Reason

Nik Graf
InstructorNik Graf

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Published 4 years ago
Updated 3 years ago

Immutability comes with lots of benefits. Working with a programming language with first class immutable data structures is a blaze. Nevertheless sometimes it can be useful to have a binding that's mutable. Using references we can achieve this in ReasonML.

Instructor: [00:01] Let bindings are mutable by default. We can make them mutable using a reference to wrap the actual value. Basically, a reference is like a box, and the content inside can change.

[00:13] To update the reference, we can use a column followed by an equals sign. We here refer to the name. The content of our foo changed to six.

[00:22] In order to retrieve the value of a reference, we can use the carrot character. References, for example, can be used to store the state of the whole game where you are, like this.

[00:49] Keep in mind to use this feature sparingly to avoid unexpected behavior. Immutability comes with lots of benefits, and you better not give them up without any good reasons.