once_cell and contants

Cargo.toml

@@ -7,3 +7,4 @@ edition = "2021"
 
 [dependencies]
 clap = { version = "4.5.16", features = ["derive"] }
+once_cell = "1.19.0"

src/main.rs

@@ -3,6 +3,8 @@ mod db;
 
 use db::{DB, Item};
 
+use once_cell::sync::Lazy;
+
 use clap::{Parser, Subcommand};
 
 use std::fs;
@@ -10,8 +12,10 @@ use std::io::{self, Write};
 use std::path::Path;
 
 
-const STORAGE_FOLDER: &str = "storage";
+static STORAGE_FOLDER: &str = "storage";
-const STORAGE_PATH: &str = "storage/db.mps"; // TODO: concat from STORAGE_FOLDER
+static STORAGE_PATH: Lazy<String> = Lazy::new(|| { 
+    format!("{}/db.mps", STORAGE_FOLDER)
+});
 
 
 #[derive(Parser)]
@@ -51,7 +55,7 @@ fn init() -> io::Result<()> {
     fs::create_dir(STORAGE_FOLDER)?;
     println!("Storage folder created");
 
-    fs::File::create(STORAGE_PATH)?;
+    fs::File::create(&*STORAGE_PATH)?;
     println!("Storage db created.");
     println!("Initialization complete.");
     println!("");
@@ -61,7 +65,7 @@ fn init() -> io::Result<()> {
 }
 
 fn add(id: &String) -> io::Result<()> {
-    let mut db = DB::new(STORAGE_PATH)?;
+    let mut db = DB::new(&*STORAGE_PATH)?;
     if db.contains(id) {
         // TODO: ask to edit existing in outer function which invoked this one
         return Err(io::Error::new(
@@ -71,13 +75,13 @@ fn add(id: &String) -> io::Result<()> {
     }
 
     db.items.insert(Item::from(id.clone()));
-    db.dump(STORAGE_PATH)?;
+    db.dump(&*STORAGE_PATH)?;
     
     Ok(())
 }
 
 fn list() -> io:: Result<()> {
-    let db = DB::new(STORAGE_PATH)?;
+    let db = DB::new(&STORAGE_PATH)?;
     let mut vec: Vec<_> = db.items.iter().collect();
     vec.sort();
     for item in &vec {