//! 수학 제58항 — 이중적분 (∬).
//!
//! Double integral ∬ (U+222C).
use crate::math_symbol_shortcut;
pub fn encode_double_integral(c: char, result: &mut Vec<u8>) -> Result<(), String> {
let encoded = math_symbol_shortcut::encode_char_math_symbol_shortcut(c)?;
result.extend_from_slice(encoded);
Ok(())
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn encodes_double_integral_symbol() {
let mut result = Vec::new();
encode_double_integral('\u{222C}', &mut result).expect("double integral should encode");
assert!(!result.is_empty());
}
}