From d77bb850ddc77d64d28458e11276434796ff70fb Mon Sep 17 00:00:00 2001
From: Asperatus <git@ballasi.com>
Date: Sun, 7 May 2023 18:34:48 -0400
Subject: [PATCH] lang: use Box<dyn Language> instead of impl Language

An overlook I did on the to_language() function caused num2words to
require `English` to be returned. Instead of this, we are using a
pointer to an element that is a Language on the heap.
---
 src/lang/en.rs   | 15 +++++----------
 src/lang/lang.rs | 16 ++++++++--------
 src/num2words.rs |  2 +-
 3 files changed, 14 insertions(+), 19 deletions(-)

diff --git a/src/lang/en.rs b/src/lang/en.rs
index 2fb4ec1..1bd6995 100644
--- a/src/lang/en.rs
+++ b/src/lang/en.rs
@@ -177,7 +177,7 @@ impl English {
 }
 
 impl Language for English {
-    fn to_cardinal(self, num: BigFloat) -> Result<String, Num2Err> {
+    fn to_cardinal(&self, num: BigFloat) -> Result<String, Num2Err> {
         if num.is_inf_pos() {
             Ok(String::from("infinity"))
         } else if num.is_inf_neg() {
@@ -189,7 +189,7 @@ impl Language for English {
         }
     }
 
-    fn to_ordinal(self, num: BigFloat) -> Result<String, Num2Err> {
+    fn to_ordinal(&self, num: BigFloat) -> Result<String, Num2Err> {
         let cardinal_word = self.to_cardinal(num)?;
 
         let mut words: Vec<String> = vec![];
@@ -246,7 +246,7 @@ impl Language for English {
         Ok(words.join(" "))
     }
 
-    fn to_ordinal_num(self, num: BigFloat) -> Result<String, Num2Err> {
+    fn to_ordinal_num(&self, num: BigFloat) -> Result<String, Num2Err> {
         Ok(format!(
             "{}{}",
             num.to_u128().unwrap(),
@@ -259,7 +259,7 @@ impl Language for English {
         ))
     }
 
-    fn to_year(self, num: BigFloat) -> Result<String, Num2Err> {
+    fn to_year(&self, num: BigFloat) -> Result<String, Num2Err> {
         if !num.frac().is_zero() {
             return Err(Num2Err::FloatingYear);
         }
@@ -297,7 +297,7 @@ impl Language for English {
         Ok(format!("{}{}", year_word, suffix))
     }
 
-    fn to_currency(self, num: BigFloat, currency: Currency) -> Result<String, Num2Err> {
+    fn to_currency(&self, num: BigFloat, currency: Currency) -> Result<String, Num2Err> {
         if num.is_inf() {
             Ok(format!(
                 "{}an infinity of {}",
@@ -638,7 +638,6 @@ mod tests {
                 .to_words(),
             Ok(String::from("infinity"))
         );
-
         assert_eq!(
             Num2Words::new(f64::NEG_INFINITY)
                 .lang(Lang::English)
@@ -646,7 +645,6 @@ mod tests {
                 .to_words(),
             Ok(String::from("minus infinity"))
         );
-
         assert_eq!(
             Num2Words::new(f64::INFINITY)
                 .lang(Lang::English)
@@ -654,7 +652,6 @@ mod tests {
                 .to_words(),
             Err(num2words::Num2Err::InfiniteOrdinal)
         );
-
         assert_eq!(
             Num2Words::new(f64::INFINITY)
                 .lang(Lang::English)
@@ -662,7 +659,6 @@ mod tests {
                 .to_words(),
             Err(num2words::Num2Err::InfiniteOrdinal)
         );
-
         assert_eq!(
             Num2Words::new(f64::INFINITY)
                 .lang(Lang::English)
@@ -670,7 +666,6 @@ mod tests {
                 .to_words(),
             Err(num2words::Num2Err::InfiniteYear)
         );
-
         assert_eq!(
             Num2Words::new(f64::INFINITY)
                 .lang(Lang::English)
diff --git a/src/lang/lang.rs b/src/lang/lang.rs
index 01d29bf..532363c 100644
--- a/src/lang/lang.rs
+++ b/src/lang/lang.rs
@@ -6,11 +6,11 @@ use std::str::FromStr;
 
 /// Defines what is a language
 pub trait Language {
-    fn to_cardinal(self, num: BigFloat) -> Result<String, Num2Err>;
-    fn to_ordinal(self, num: BigFloat) -> Result<String, Num2Err>;
-    fn to_ordinal_num(self, num: BigFloat) -> Result<String, Num2Err>;
-    fn to_year(self, num: BigFloat) -> Result<String, Num2Err>;
-    fn to_currency(self, num: BigFloat, currency: Currency) -> Result<String, Num2Err>;
+    fn to_cardinal(&self, num: BigFloat) -> Result<String, Num2Err>;
+    fn to_ordinal(&self, num: BigFloat) -> Result<String, Num2Err>;
+    fn to_ordinal_num(&self, num: BigFloat) -> Result<String, Num2Err>;
+    fn to_year(&self, num: BigFloat) -> Result<String, Num2Err>;
+    fn to_currency(&self, num: BigFloat, currency: Currency) -> Result<String, Num2Err>;
 }
 
 /// Languages available in `num2words`
@@ -42,7 +42,7 @@ impl FromStr for Lang {
     }
 }
 
-pub fn to_language(lang: Lang, preferences: Vec<String>) -> impl Language {
+pub fn to_language(lang: Lang, preferences: Vec<String>) -> Box<dyn Language> {
     match lang {
         Lang::English => {
             let last = preferences
@@ -51,10 +51,10 @@ pub fn to_language(lang: Lang, preferences: Vec<String>) -> impl Language {
                 .last();
 
             if let Some(v) = last {
-                return lang::English::new(v == "oh", v == "nil");
+                return Box::new(lang::English::new(v == "oh", v == "nil"));
             }
 
-            lang::English::new(false, false)
+            Box::new(lang::English::new(false, false))
         }
     }
 }
diff --git a/src/num2words.rs b/src/num2words.rs
index 1428d1f..f9d4231 100644
--- a/src/num2words.rs
+++ b/src/num2words.rs
@@ -1,4 +1,4 @@
-use crate::{lang, Currency, Lang, Language, Output};
+use crate::{lang, Currency, Lang, Output};
 use num_bigfloat::BigFloat;
 
 /// Error type returned by the builder