Example of how to look at next rune when iterating a string

peek_at_next_rune.odin

package runefun

import fmt "core:fmt"
import "core:unicode/utf8"

main :: proc() {
	str := "小猫咪"
	
	// i is the byte index
	for r, i in str {
		// byte index of next rune
		next_idx := i+utf8.rune_size(r)

		if next_idx < len(str) {
			// rune_at expects byte index
			next_rune := utf8.rune_at(str, next_idx)
			fmt.println(next_rune)
		}
	}
}

// This program will print
// 猫
// 咪
// I.e. it looks ahead at next rune at each lap of the loop.

// Note: There is also utf8.rune_at_pos(str, rune_idx) that takes a rune index.
// But internally it does a loop over the string to find the rune with that index,
// it is better to just use the rune_at with a byte index, it does no looping.