Improve formatting of numbers, closes #20

Author: probablykasper

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## Next
+- Improve formatting of numbers
+
 ## 1.9.0 - 2022 Dec 30
 - Add `marathon` unit
 - Add `aarch64` binaries

README.md

@@ -39,7 +39,7 @@ match eval("3m + 1cm", true, Unit::Celsius, false) {
         println!("Evaluated value: {} {:?}", answer.value, answer.unit)
     },
     Err(e) => {
-        println!("{}", e)
+        println!("{e}")
     }
 }
 ```

src/lexer.rs

@@ -952,22 +952,22 @@ mod tests {
 				}
 			};
 			let info_msg = format!("run_lex input: {}\nexpected: {:?}\nreceived: {:?}", input, expected_tokens, tokens);
-			assert!(tokens == expected_tokens, "{}", info_msg);
+			assert!(tokens == expected_tokens, "{info_msg}");
 
 			// Prove we can handle multiple spaces wherever we handle a single space
 			let input_extra_spaces = input.replace(" ", "   ");
 			let tokens_extra_spaces = lex(&input_extra_spaces, false, Unit::Celsius).unwrap();
-			assert!(tokens_extra_spaces == expected_tokens, "{}", info_msg);
+			assert!(tokens_extra_spaces == expected_tokens, "{info_msg}");
 
 			// Prove we don't need spaces around operators
 			let input_stripped_spaces = strip_operator_spacing.replace_all(input, "$1");
 			let tokens_stripped_spaces = lex(&input_stripped_spaces, false, Unit::Celsius).unwrap();
-			assert!(tokens_stripped_spaces == expected_tokens, "{}", info_msg);
+			assert!(tokens_stripped_spaces == expected_tokens, "{info_msg}");
 
 			// Prove we don't need a space after a digit
 			let input_afterdigit_stripped_spaces = strip_afterdigit_spacing.replace_all(input, "$1");
 			let tokens_afterdigit_stripped_spaces = lex(&input_afterdigit_stripped_spaces, false, Unit::Celsius).unwrap();
-			assert!(tokens_afterdigit_stripped_spaces == expected_tokens, "{}", info_msg);
+			assert!(tokens_afterdigit_stripped_spaces == expected_tokens, "{info_msg}");
 		};
 
 		let run_datarate_lex = |input: &str, expected_tokens: Vec<Token>| {
@@ -977,7 +977,7 @@ mod tests {
 			let input_nonplural_units = nonplural_data_units.replace_all(input, "$1");
 			let tokens_nonplural_units = lex(&input_nonplural_units, false, Unit::Celsius).unwrap();
 			let info_msg = format!("run_datarate_lex input: {}\nexpected: {:?}\nreceived: {:?}", input, expected_tokens, tokens_nonplural_units);
-			assert!(tokens_nonplural_units == expected_tokens, "{}", info_msg);
+			assert!(tokens_nonplural_units == expected_tokens, "{info_msg}");
 		};
 
 		run_lex("88 kilometres * 2", vec![numtok!(88), Token::Unit(Kilometer), Token::Operator(Multiply), numtok!(2)]);

src/lib.rs

@@ -25,7 +25,7 @@
 //!         println!("Evaluated value: {} {:?}", answer.value, answer.unit)
 //!     },
 //!     Err(e) => {
-//!         println!("{}", e)
+//!         println!("{e}")
 //!     }
 //! }
 //! ```
@@ -77,12 +77,16 @@ impl Number {
 impl Display for Number {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		// 0.2/0.01 results in 2E+1, but if we add zero it becomes 20
-		let fixed_value = self.value + d128!(0);
-		let output = match self.unit {
-			Unit::NoUnit => format!("{}", fixed_value),
-			unit => format!("{} {:?}", fixed_value, unit),
+		let value = self.value + d128!(0);
+		let word = match self.value == d128!(1) {
+			true => self.unit.singular(),
+			false => self.unit.plural(),
 		};
-		write!(f, "{}", output)
+		let output = match word {
+			"" => format!("{value}"),
+			_ => format!("{value} {word}"),
+		};
+		write!(f, "{output}")
 	}
 }
 
@@ -232,7 +236,7 @@ macro_rules! numtok {
 ///         println!("Evaluated value: {} {:?}", answer.value, answer.unit)
 ///     },
 ///     Err(e) => {
-///         println!("{}", e)
+///         println!("{e}")
 ///     }
 /// }
 /// ```

src/main.rs

@@ -28,7 +28,7 @@ fn main() {
 	for arg in get_args() {
 		match arg.as_str() {
 			"--version" => {
-				println!("{}", VERSION);
+				println!("{VERSION}");
 				exit(0);
 			}
 			"--help" => {
@@ -64,11 +64,11 @@ fn main() {
 	match eval(&expression, true, Unit::Celsius, verbose) {
 		Ok(answer) => {
 			if !verbose {
-				println!("{}", answer);
+				println!("{answer}");
 			}
 		}
 		Err(e) => {
-			eprintln!("{}", e);
+			eprintln!("{e}");
 			exit(1);
 		}
 	}