[mrkeen]

> it seems that with signals you must use immutable values only. Imagine if you have, let's say, a text document model, and you need to create a new copy every time the user types a letter.

Too small. Imagine if you have a 2GB mutable file. Each keystroke in the middle of the file has to move the whole 2nd gigabyte backward.

[naasking]

Immutable representations of large buffers aren't flat arrays. The most obvious abstract semantics that we're depending on here is a map from indexes to byte segments. Immutably rearranging indexes can be made very fast.