You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: themes.rs
    path of file: ./repos/rustrogueliketutorial/chapter-62-magicitems/src/map
    
    the code of the file until where you have to start completion: use super::{Map, TileType};
use rltk::RGB;

pub fn tile_glyph(idx: usize, map : &Map) -> (rltk::FontCharType, RGB, RGB) {
    let (glyph, mut fg, mut bg) = match map.depth {
        5 => {
            let x = idx as i32 % map.width;
            if x < map.width/2 {
                get_limestone_cavern_glyph(idx, map)
            } else {
                get_tile_glyph_default(idx, map)
            }
        }
        4 => get_limestone_cavern_glyph(idx, map),
        3 => get_limestone_cavern_glyph(idx, map),
        2 => get_forest_glyph(idx, map),
        _ => get_til
    
fn wall_glyph(map : &Map, x: i32, y:i32) -> rltk::FontCharType {
    if x < 1 || x > map.width-2 || y < 1 || y > map.height-2 as i32 { return 35; }
    let mut mask : u8 = 0;

    if is_revealed_and_wall(map, x, y - 1) { mask +=1; }
    if is_revealed_and_wall(map, x, y + 1) { mask +=2; }
    if is_revealed_and_wall(map, x - 1, y) { mask +=4; }
    if is_revealed_and_wall(map, x + 1, y) { mask +=8; }

    match mask {
        0 => { 9 } // Pillar because we can't see neighbors
        1 => { 186 } // Wall only to the north
        2 => { 186 } // Wall only to the south
        3 => { 186 } // Wall to the north and south
        4 => { 205 } // Wall only to the west
        5 => { 188 } // Wall to the north and west
        6 => { 187 } // Wall to the south and west
        7 => { 185 } // Wall to the north, south and west
        8 => { 205 } // Wall only to the east
        9 => { 200 } // Wall to the north and east
        10 => { 201 } // Wall to the south and east
        11 => { 204 } // Wall to the north, south and east
        12 => { 205 } // Wall to the east and west
        13 => { 202 } // Wall to the east, west, and south
        14 => { 203 } // Wall to the east, west, and north
        15 => { 206 }  // ╬ Wall on all sides
        _ => { 35 } // We missed one?
    }
}