String range to dchar.

[Samuel Pike via Digitalmars-d-learn]

Hi all.

First time posting here. I recently downloaded the dmd compiler 
and started making a few exercises with the language. Nice 
language features but still somewhat confused with the library.

If I use byDchar() over a "string" is there a possibility to get 
part of a character or is guaranteed that the entire visual 
character will be in the dchar?

Also, is there a way to peek into a range? Maybe a range that 
buffers its items when calling peek()?

Thank you