Optimize for 3 char currency-codes, since ECB only sends those

Cargo.lock

@@ -91,15 +91,6 @@ version = "2.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "812e12b5285cc515a9c72a5c1d3b6d46a19dac5acfef5265968c166106e31dd3"
 
-[[package]]
-name = "borsh"
-version = "1.6.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d1da5ab77c1437701eeff7c88d968729e7766172279eab0676857b3d63af7a6f"
-dependencies = [
- "cfg_aliases",
-]
-
 [[package]]
 name = "bumpalo"
 version = "3.19.1"
@@ -128,12 +119,6 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
-[[package]]
-name = "cfg_aliases"
-version = "0.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "613afe47fcd5fac7ccf1db93babcb082c5994d996f20b8b159f2ad1658eb5724"
-
 [[package]]
 name = "chrono"
 version = "0.4.42"
@@ -232,7 +217,7 @@ dependencies = [
 
 [[package]]
 name = "ecb-rates"
-version = "1.1.0"
+version = "1.0.1"
 dependencies = [
  "anyhow",
  "chrono",
@@ -242,7 +227,6 @@ dependencies = [
  "reqwest",
  "serde",
  "serde_json",
- "smol_str",
  "tokio",
 ]
 
@@ -977,9 +961,9 @@ dependencies = [
 
 [[package]]
 name = "rustls-pki-types"
-version = "1.13.2"
+version = "1.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "21e6f2ab2928ca4291b86736a8bd920a277a399bba1589409d72154ff87c1282"
+checksum = "708c0f9d5f54ba0272468c1d306a52c495b31fa155e91bc25371e6df7996908c"
 dependencies = [
  "zeroize",
 ]
@@ -1112,16 +1096,6 @@ version = "1.15.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "67b1b7a3b5fe4f1376887184045fcf45c69e92af734b7aaddc05fb777b6fbd03"
 
-[[package]]
-name = "smol_str"
-version = "0.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3498b0a27f93ef1402f20eefacfaa1691272ac4eca1cdc8c596cb0a245d6cbf5"
-dependencies = [
- "borsh",
- "serde_core",
-]
-
 [[package]]
 name = "socket2"
 version = "0.6.1"
@@ -1236,9 +1210,21 @@ dependencies = [
  "mio",
  "pin-project-lite",
  "socket2",
+ "tokio-macros",
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "tokio-macros"
+version = "2.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af407857209536a95c8e56f8231ef2c2e2aff839b22e07a1ffcbc617e9db9fa5"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "tokio-native-tls"
 version = "0.3.1"

Cargo.toml

@@ -1,10 +1,11 @@
 [package]
 name = "ecb-rates"
 description = "Query exchange rates from the European Central Bank (ECB)"
-version = "1.1.0"
-edition = "2024"
+version = "1.0.1"
+edition = "2021"
 authors = ["Love Billenius <lovebillenius@disroot.org>"]
 license = "Zlib"
+license-file = "LICENSE"
 keywords = [
     "ECB",
     "Bank",
@@ -13,7 +14,7 @@ keywords = [
     "rates",
 ]
 repository = "https://github.com/lov3b/ecb-rates"
-rust-version = "1.92"
+rust-version = "1.83"
 categories = ["finance", "command-line-utilities"]
 
 [profile.release]
@@ -33,5 +34,4 @@ quick-xml = { version = "0.38", features = ["async-tokio", "tokio"] }
 reqwest = "0.12"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
-smol_str = { version = "0.3", features = ["serde"] }
-tokio = "1.48"
+tokio = { version = "1.48", features = ["macros"] }

src/cache/cache.rs

@@ -3,8 +3,8 @@ use std::io::{BufReader, BufWriter};
 use std::path::{Path, PathBuf};
 
 use super::CacheLine;
-use crate::View;
 use crate::os::Os;
+use crate::View;
 
 #[derive(Debug)]
 pub struct Cache {

src/cache/cache_line.rs

@@ -4,8 +4,8 @@ use chrono::serde::ts_seconds;
 use chrono::{DateTime, Datelike, FixedOffset, Local, NaiveDate, TimeDelta, Utc, Weekday};
 use serde::{Deserialize, Serialize};
 
-use crate::Hollidays;
 use crate::models::ExchangeRateResult;
+use crate::Hollidays;
 
 const CET: FixedOffset = unsafe { FixedOffset::east_opt(3600).unwrap_unchecked() };
 

src/cli/cli_t.rs

@@ -1,14 +1,14 @@
-use clap::{Parser, ValueEnum};
-use smol_str::SmolStr;
+use clap::{arg, Parser, ValueEnum};
 
 use super::{ShowDays, SortBy};
 
 #[derive(Debug, Parser)]
 #[command(author, version, about)]
+
 pub struct Cli {
     /// Which currencies do you want to fetch rates for?
     #[arg(long = "currencies", short = 'c')]
-    pub currencies: Vec<SmolStr>,
+    pub currencies: Vec<String>,
 
     #[arg(value_enum, default_value_t = FormatOption::Plain)]
     pub command: FormatOption,
@@ -35,13 +35,13 @@ pub struct Cli {
 
     /// Recalculate to the perspective from an included currency
     #[arg(long = "perspective", short = 'p')]
-    pub perspective: Option<SmolStr>,
+    pub perspective: Option<String>,
 
     /// Invert the rate
     #[arg(long = "invert", short = 'i')]
     pub should_invert: bool,
 
-    /// Max decimals to keep in price.
+    //// Max decimals to keep in price.
     #[arg(long = "max-decimals", short = 'd', default_value_t = 5)]
     pub max_decimals: u8,
 

src/cli/sort_by.rs

@@ -1,5 +1,7 @@
 use clap::ValueEnum;
 
+use crate::models::Currency;
+
 #[derive(Debug, ValueEnum, Clone)]
 pub enum SortBy {
     Currency,
@@ -7,9 +9,9 @@ pub enum SortBy {
 }
 
 impl SortBy {
-    pub fn get_comparer(&self) -> fn(&(&str, f64), &(&str, f64)) -> std::cmp::Ordering {
+    pub fn get_comparer(&self) -> fn(&(&Currency, f64), &(&Currency, f64)) -> std::cmp::Ordering {
         match self {
-            Self::Currency => |a, b| a.0.cmp(b.0),
+            Self::Currency => |a, b| a.0.as_ref().cmp(b.0.as_ref()),
             Self::Rate => |a, b| a.1.total_cmp(&b.1),
         }
     }

src/header_description.rs

@@ -7,12 +7,6 @@ pub struct HeaderDescription<'a> {
     header_description: [&'a str; 2],
 }
 
-impl<'a> Default for HeaderDescription<'a> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
 impl<'a> HeaderDescription<'a> {
     pub fn new() -> Self {
         Self {

src/lib.rs

@@ -1,4 +1,4 @@
-pub mod caching;
+pub mod cache;
 pub mod cli;
 mod header_description;
 mod holiday;
@@ -13,15 +13,16 @@ pub use header_description::HeaderDescription;
 pub use holiday::Hollidays;
 pub use view::View;
 
-const APP_NAME: &str = "ECB-rates";
+const APP_NAME: &'static str = "ECB-rates";
 const DEFAULT_WIDTH: usize = 20;
 
 pub mod ecb_url {
-    pub const TODAY: &str = "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml";
+    pub const TODAY: &'static str = "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml";
 
     pub mod hist {
-        pub const DAYS_ALL: &str = "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-hist.xml";
-        pub const DAYS_90: &str =
+        pub const DAYS_ALL: &'static str =
+            "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-hist.xml";
+        pub const DAYS_90: &'static str =
             "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-hist-90d.xml";
     }
 }

src/main.rs

@@ -1,13 +1,12 @@
-use anyhow::Context;
 use clap::Parser as _;
-use ecb_rates::caching::{Cache, CacheLine};
+use ecb_rates::cache::{Cache, CacheLine};
 use ecb_rates::HeaderDescription;
 use reqwest::{Client, IntoUrl};
-use smol_str::StrExt;
 use std::process::ExitCode;
+use std::str::FromStr;
 
 use ecb_rates::cli::{Cli, FormatOption};
-use ecb_rates::models::ExchangeRateResult;
+use ecb_rates::models::{Currency, ExchangeRateResult};
 use ecb_rates::parsing::parse;
 use ecb_rates::table::{TableRef, TableTrait as _};
 use ecb_rates::utils_calc::{change_perspective, filter_currencies, invert_rates, round};
@@ -18,40 +17,22 @@ async fn get_and_parse(url: impl IntoUrl) -> anyhow::Result<Vec<ExchangeRateResu
     parse(&xml_content)
 }
 
-fn main() -> ExitCode {
-    let cli = Cli::parse();
-
-    let runtime = match tokio::runtime::Builder::new_current_thread()
-        .enable_all()
-        .build()
-    {
-        Ok(runtime) => runtime,
-        Err(e) => {
-            eprintln!("Failed to initialize asynchronous runtime: {:?}", e);
-            return ExitCode::FAILURE;
-        }
-    };
-
-    match runtime.block_on(async_main(cli)) {
-        Ok(_) => ExitCode::SUCCESS,
-        Err(e) => {
-            eprintln!("Fatal: {:?}", e);
-            ExitCode::FAILURE
-        }
-    }
-}
-
-async fn async_main(mut cli: Cli) -> anyhow::Result<()> {
+#[tokio::main(flavor = "current_thread")]
+async fn main() -> ExitCode {
+    let mut cli = Cli::parse();
     if cli.force_color {
         colored::control::set_override(true);
     }
 
     let mut header_description = HeaderDescription::new();
     let use_cache = !cli.no_cache;
-    let view = cli
-        .show_days
-        .to_view()
-        .context("It doesn't make any sence to fetch 0 days right?")?;
+    let view = match cli.show_days.to_view() {
+        Some(v) => v,
+        None => {
+            eprintln!("It doesn't make any sence to fetch 0 days right?");
+            return ExitCode::SUCCESS;
+        }
+    };
     let mut cache = if use_cache { Cache::load(&view) } else { None };
     let cache_ok = cache.as_ref().map_or_else(
         || false,
@@ -67,9 +48,14 @@ async fn async_main(mut cli: Cli) -> anyhow::Result<()> {
             .exchange_rate_results
             .clone()
     } else {
-        let parsed = get_and_parse(view.to_ecb_url())
-            .await
-            .context("Failed to get/parse data from ECB")?;
+        let parsed = match get_and_parse(view.to_ecb_url()).await {
+            Ok(k) => k,
+            Err(e) => {
+                eprintln!("Failed to get/parse data from ECB: {}", e);
+                return ExitCode::FAILURE;
+            }
+        };
+
         if !cache_ok {
             let not_equal_cache = cache.as_ref().map_or_else(
                 || true,
@@ -80,20 +66,37 @@ async fn async_main(mut cli: Cli) -> anyhow::Result<()> {
                 },
             );
 
-            if not_equal_cache && let Some(cache_safe) = cache.as_mut() {
+            if not_equal_cache {
+                if let Some(cache_safe) = cache.as_mut() {
                     let cache_line = CacheLine::new(parsed.clone());
                     cache_safe.set_cache_line(cache_line);
-                cache_safe.save()?;
+                    if let Err(e) = cache_safe.save() {
+                        eprintln!("Failed to save to cache with: {:?}", e);
+                    }
+                }
             }
         }
         parsed
     };
 
-    cli.perspective = cli.perspective.map(|s| s.to_uppercase_smolstr());
-    if let Some(currency) = cli.perspective.as_ref() {
-        header_description.replace_eur(currency);
-        change_perspective(&mut parsed, currency)
-            .context("The currency wasn't in the data from the ECB!")?;
+    cli.perspective = cli.perspective.map(|s| s.to_uppercase());
+    let parsed_currency = match cli.perspective.as_ref() {
+        Some(currency) => match Currency::from_str(currency) {
+            Ok(k) => Some(k),
+            Err(e) => {
+                eprintln!("The currency code '{}' is invalid: {:?}", currency, e);
+                return ExitCode::FAILURE;
+            }
+        },
+        None => None,
+    };
+    if let Some(currency) = parsed_currency.as_ref() {
+        header_description.replace_eur(currency.as_ref());
+        let error_occured = change_perspective(&mut parsed, &currency).is_none();
+        if error_occured {
+            eprintln!("The currency wasn't in the data from the ECB!");
+            return ExitCode::FAILURE;
+        }
     }
 
     if cli.should_invert {
@@ -104,11 +107,19 @@ async fn async_main(mut cli: Cli) -> anyhow::Result<()> {
     round(&mut parsed, cli.max_decimals);
 
     if !cli.currencies.is_empty() {
-        let currencies = cli
+        let currencies = match cli
             .currencies
             .iter()
-            .map(|x| x.to_uppercase_smolstr())
-            .collect::<Vec<_>>();
+            .map(|x| x.to_uppercase())
+            .map(|x| Currency::from_str(&x))
+            .collect::<anyhow::Result<Vec<_>>>()
+        {
+            Ok(k) => k,
+            Err(e) => {
+                eprintln!("Failed to parse currenc(y/ies): {:?}", e);
+                return ExitCode::FAILURE;
+            }
+        };
 
         filter_currencies(&mut parsed, &currencies);
     }
@@ -168,5 +179,5 @@ async fn async_main(mut cli: Cli) -> anyhow::Result<()> {
     };
 
     println!("{}", &output);
-    Ok(())
+    ExitCode::SUCCESS
 }

src/models/currency.rs

@@ -0,0 +1,97 @@
+use std::{
+    fmt,
+    ops::Index,
+    slice::Iter,
+    str::{self, FromStr},
+};
+
+use serde::{de, Deserialize, Serialize};
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct Currency {
+    name: [u8; 3],
+}
+
+impl Currency {
+    pub fn as_str(&self) -> &str {
+        // SAFETY: We validate that bytes are ASCII in FromStr.
+        unsafe { str::from_utf8_unchecked(&self.name) }
+    }
+
+    pub fn iter(&self) -> Iter<'_, u8> {
+        self.name.iter()
+    }
+}
+
+impl AsRef<str> for Currency {
+    fn as_ref(&self) -> &str {
+        self.as_str()
+    }
+}
+
+impl Serialize for Currency {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        serializer.serialize_str(self.as_str())
+    }
+}
+
+impl<'de> Deserialize<'de> for Currency {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de>,
+    {
+        let s = String::deserialize(deserializer)?;
+        FromStr::from_str(&s).map_err(de::Error::custom)
+    }
+}
+
+impl FromStr for Currency {
+    type Err = anyhow::Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if s.len() != 3 {
+            anyhow::bail!("Currency code must be exactly 3 chars");
+        }
+        if !s.is_ascii() {
+            anyhow::bail!("Currency code must be ASCII");
+        }
+
+        let b = s.as_bytes();
+        Ok(Self {
+            name: [b[0], b[1], b[2]],
+        })
+    }
+}
+
+impl TryFrom<&str> for Currency {
+    type Error = anyhow::Error;
+    fn try_from(value: &str) -> Result<Self, Self::Error> {
+        Currency::from_str(value)
+    }
+}
+
+impl fmt::Display for Currency {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
+impl Index<usize> for Currency {
+    type Output = u8;
+
+    fn index(&self, index: usize) -> &Self::Output {
+        &self.name[index]
+    }
+}
+
+impl<'a> IntoIterator for &'a Currency {
+    type Item = &'a u8;
+    type IntoIter = Iter<'a, u8>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.iter()
+    }
+}

src/models/exchange_rate_result.rs

@@ -1,9 +1,10 @@
 use serde::{Deserialize, Serialize};
-use smol_str::SmolStr;
 use std::collections::HashMap;
 
+use super::Currency;
+
 #[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
 pub struct ExchangeRateResult {
-    pub time: SmolStr,
-    pub rates: HashMap<SmolStr, f64>,
+    pub time: String,
+    pub rates: HashMap<Currency, f64>,
 }

src/models/mod.rs

@@ -0,0 +1,5 @@
+mod currency;
+mod exchange_rate_result;
+
+pub use currency::Currency;
+pub use exchange_rate_result::ExchangeRateResult;

src/parsing.rs

@@ -1,52 +1,45 @@
-use std::collections::HashMap;
+use std::{collections::HashMap, str::FromStr};
 
-use quick_xml::Reader;
 use quick_xml::events::Event;
-use smol_str::SmolStr;
+use quick_xml::Reader;
 
-use crate::models::ExchangeRateResult;
-
-fn smol_from_utf8(bytes: &[u8]) -> SmolStr {
-    str::from_utf8(bytes)
-        .map(SmolStr::new)
-        .unwrap_or_else(|_| SmolStr::new(String::from_utf8_lossy(bytes)))
-}
+use crate::models::{Currency, ExchangeRateResult};
 
 pub fn parse(xml: &str) -> anyhow::Result<Vec<ExchangeRateResult>> {
     let mut reader = Reader::from_str(xml);
     reader.config_mut().trim_text(true);
 
     let mut results = Vec::new();
-    let mut current_time: Option<SmolStr> = None;
+    let mut current_time: Option<String> = None;
     let mut inside_cube_time = false;
     let mut current_rates = HashMap::new();
 
     fn handle_cube_element(
         e: &quick_xml::events::BytesStart,
-        current_time: &mut Option<SmolStr>,
+        current_time: &mut Option<String>,
         inside_cube_time: &mut bool,
-        current_rates: &mut HashMap<SmolStr, f64>,
+        current_rates: &mut HashMap<Currency, f64>,
         results: &mut Vec<ExchangeRateResult>,
     ) -> anyhow::Result<()> {
         if e.name().local_name().as_ref() != b"Cube" {
             return Ok(());
         }
 
-        let mut time_attr: Option<SmolStr> = None;
-        let mut currency_attr: Option<SmolStr> = None;
-        let mut rate_attr: Option<SmolStr> = None;
+        let mut time_attr: Option<String> = None;
+        let mut currency_attr: Option<Currency> = None;
+        let mut rate_attr: Option<String> = None;
 
         for attr_result in e.attributes() {
             let attr = attr_result?;
             let key = attr.key.as_ref();
-            let val = smol_from_utf8(attr.value.as_ref());
+            let val = String::from_utf8_lossy(attr.value.as_ref()).to_string();
 
             match key {
                 b"time" => {
                     time_attr = Some(val);
                 }
                 b"currency" => {
-                    currency_attr = Some(val);
+                    currency_attr = Some(Currency::from_str(&val)?);
                 }
                 b"rate" => {
                     rate_attr = Some(val);
@@ -68,10 +61,12 @@ pub fn parse(xml: &str) -> anyhow::Result<Vec<ExchangeRateResult>> {
             *inside_cube_time = true;
         }
 
-        if *inside_cube_time && let (Some(c), Some(r_str)) = (currency_attr, rate_attr) {
+        if *inside_cube_time {
+            if let (Some(c), Some(r_str)) = (currency_attr, rate_attr) {
                 let r = r_str.parse::<f64>()?;
                 current_rates.insert(c, r);
             }
+        }
 
         Ok(())
     }

src/table/mod.rs

@@ -1,10 +1,11 @@
-mod table_display;
 mod table_getter;
 mod table_owned;
 mod table_ref;
 mod table_trait;
+mod table_display;
 
 pub use table_getter::TableGet;
 pub use table_owned::Table;
 pub use table_ref::TableRef;
 pub use table_trait::TableTrait;
+

src/table/table_owned.rs

@@ -1,29 +1,27 @@
 use std::fmt::Display;
 
-use smol_str::SmolStr;
-
-use crate::DEFAULT_WIDTH;
 use crate::cli::SortBy;
-use crate::models::ExchangeRateResult;
+use crate::models::{Currency, ExchangeRateResult};
+use crate::DEFAULT_WIDTH;
 
 use super::table_display::helper_table_print;
 use super::{TableGet, TableTrait};
 
 pub struct Table {
-    pub(super) header: Option<SmolStr>,
-    pub(super) column_left: SmolStr,
-    pub(super) column_right: SmolStr,
-    pub(super) rows: Vec<(SmolStr, f64)>,
+    pub(super) header: Option<String>,
+    pub(super) column_left: String,
+    pub(super) column_right: String,
+    pub(super) rows: Vec<(Currency, f64)>,
     pub color: bool,
     pub width: usize,
     pub left_offset: usize,
 }
 
 impl<'a> TableTrait<'a> for Table {
-    type Header = SmolStr;
-    type ColumnLeft = SmolStr;
-    type ColumnRight = SmolStr;
-    type RowLeft = SmolStr;
+    type Header = String;
+    type ColumnLeft = String;
+    type ColumnRight = String;
+    type RowLeft = Currency;
 
     fn new(
         header: Option<Self::Header>,
@@ -61,8 +59,8 @@ impl<'a> TableTrait<'a> for Table {
 }
 
 impl TableGet for Table {
-    type RowLeftRef = SmolStr;
-    type RowRightRef = SmolStr;
+    type RowLeftRef = Currency;
+    type RowRightRef = String;
 
     fn get_header(&self) -> Option<&str> {
         self.header.as_deref()
@@ -87,7 +85,7 @@ impl TableGet for Table {
 
 impl From<ExchangeRateResult> for Table {
     fn from(value: ExchangeRateResult) -> Self {
-        let mut table = Table::new(Some(value.time), "Currency".into(), "Rate".into());
+        let mut table = Table::new(Some(value.time), "Currency".to_string(), "Rate".to_string());
         for (key, val) in value.rates.into_iter() {
             table.add_row(key, val);
         }

src/table/table_ref.rs

@@ -1,19 +1,19 @@
 use std::fmt::Display;
 
-use crate::DEFAULT_WIDTH;
 use crate::cli::SortBy;
-use crate::models::ExchangeRateResult;
+use crate::models::{Currency, ExchangeRateResult};
+use crate::DEFAULT_WIDTH;
 
-use super::Table;
 use super::table_display::helper_table_print;
 use super::table_getter::TableGet;
 use super::table_trait::TableTrait;
+use super::Table;
 
 pub struct TableRef<'a> {
     header: Option<&'a str>,
     column_left: &'a str,
     column_right: &'a str,
-    rows: Vec<(&'a str, f64)>,
+    rows: Vec<(&'a Currency, f64)>,
     pub color: bool,
     pub width: usize,
     pub left_offset: usize,
@@ -23,7 +23,7 @@ impl<'a> TableTrait<'a> for TableRef<'a> {
     type Header = &'a str;
     type ColumnLeft = &'a str;
     type ColumnRight = &'a str;
-    type RowLeft = &'a str;
+    type RowLeft = &'a Currency;
 
     fn new(
         header: Option<Self::Header>,
@@ -60,7 +60,7 @@ impl<'a> TableTrait<'a> for TableRef<'a> {
 }
 
 impl<'a> TableGet for TableRef<'a> {
-    type RowLeftRef = &'a str;
+    type RowLeftRef = &'a Currency;
     type RowRightRef = &'a str;
 
     fn get_header(&self) -> Option<&str> {
@@ -106,7 +106,7 @@ impl<'a> From<&'a Table> for TableRef<'a> {
         let rows = table
             .rows
             .iter()
-            .map(|(left, right)| (left.as_str(), *right))
+            .map(|(left, right)| (left, *right))
             .collect();
 
         TableRef {

src/utils_calc.rs

@@ -1,12 +1,13 @@
-use std::{borrow::BorrowMut, collections::HashMap, ops::Deref};
+use std::{borrow::BorrowMut, collections::HashMap, ops::Deref, str::FromStr};
 
-use smol_str::SmolStr;
+use crate::models::{Currency, ExchangeRateResult};
 
-use crate::models::ExchangeRateResult;
-
-pub fn filter_currencies(exchange_rate_results: &mut [ExchangeRateResult], currencies: &[SmolStr]) {
+pub fn filter_currencies(
+    exchange_rate_results: &mut [ExchangeRateResult],
+    currencies: &[Currency],
+) {
     for exchange_rate in exchange_rate_results {
-        let rates_ptr: *mut HashMap<_, _> = &mut exchange_rate.rates;
+        let rates_ptr: *mut HashMap<Currency, f64> = &mut exchange_rate.rates;
         exchange_rate
             .rates
             .keys()
@@ -24,7 +25,7 @@ pub fn filter_currencies(exchange_rate_results: &mut [ExchangeRateResult], curre
 
 pub fn change_perspective(
     exchange_rate_results: &mut [ExchangeRateResult],
-    currency: &str,
+    currency: &Currency,
 ) -> Option<()> {
     for rate_res in exchange_rate_results {
         let currency_rate = rate_res.rates.remove(currency)?;
@@ -34,7 +35,10 @@ pub fn change_perspective(
             *iter_rate = eur_rate * iter_rate.deref();
         }
 
-        rate_res.rates.insert("EUR".into(), eur_rate);
+        rate_res.rates.insert(
+            unsafe { Currency::from_str("EUR").unwrap_unchecked() },
+            eur_rate,
+        );
     }
     Some(())
 }