Add `byteAt(index)`, `codePointAt(index)`, and `bytes` sequence to String, enabling direct byte-level manipulation of UTF-8 encoded strings. Introduce `\x` hex escape sequence in string literals for specifying raw byte values. Refactor Unicode escape parsing into a generic `readHexEscape` function supporting variable digit counts. Implement `wrenUtf8Decode` utility for decoding UTF-8 sequences from byte buffers. Add comprehensive tests for `byteAt` including boundary conditions and error cases.
The Wren scripts in this directory get converted to C string literals and then inserted into their respective .c files so that the interpreter can load them directly without having to do any file IO.
The script that does this copying is script/generate_builtins.py.
You can invoke using make builtin.