A more interesting question: what would our code look like if ASCII (or strings in general) didn't have escape codes?
How do you make the carriage (a literal thing on a chain being driven back and forth) "return" to the start of the line without a "carriage return" code?
How would you make the paper feed go up one line without a "line feed" code?
Same for ringing the bell, tabs, backspace etc.
A "new line" on a teletype was actually two characters, a CR and a LF.
Unfortunately, using one of the other sequences (eg RS, for "Record Separator") would have saved billions of CPU cycles and misinterpreted text files dealing with the CRLF, CR, LF, LFCR sequences to mean "new line".
ASCII is the layer that doesn't have escape codes (although it does have a single code for ESC), ascii is just a set of mappings from 7-bit numbers to/from mostly-printable characters
Terminal control is fairly easy answer, there would be some other API to control cursor position, so the code would need to call some function to move the cursor to next line.
For files, it would depend on what the format is. So we might be writing just `<p>hello world</p>` instead of `hello world\n`. In fact I find it bit weird that we are using teletype (and telegraph etc) control protocol (what ASCII mostly is) as our "general purpose text" format; it doesn't make much sense to me.
This is what `chr(39)` is for in the following Python quine:
a = 'a = {}{}{}; print(a.format(chr(39), a, chr(39)))'; print(a.format(chr(39), a, chr(39)))
a = '''a = {}
print(a.format(repr(a)))'''
print(a.format(repr(a)))
The actual quine is the slightly less readable:
a = 'a = {}\nprint(a.format(repr(a)))'
print(a.format(repr(a)))
Perhaps like [0] (Unicode notation).