But a text editor to open a file you won't ever edit is maybe also not the best idea. A pure text viewer can use different data structures that don't have to an

But a text editor to open a file you won't ever edit is maybe also not the best idea. A pure text viewer can use different data structures that don't have to anticipate edits to the text and likely be faster. Or, on the other hand, a text editor trying to optimise the use case where people open large files without editing them (or only editing tiny portions of it), will likely grow a lot more complex.