Fix numbers unnecessarily displayed in E notation

Author: probablykasper

README.md

@@ -164,6 +164,9 @@ match string {
 
 ### Potential Improvements
 - Support for conversion between Power, Current, Resistance and Voltage. Multiplication and division is currently supported, but not conversions using sqrt or pow.
+- Move to pure-rust decimal implementation
+  - `rust_decimal`: Only supports numbers up to ~1E+29
+  - `bigdecimal`: Lacking math functions
 - E notation, like 2E+10
 - Unit types
   - Currency: How to go about dynamically updating the weights?

src/lib.rs

@@ -22,6 +22,7 @@
 //! }
 //! ```
 
+use std::fmt::{self, Display};
 use std::time::{Instant};
 use decimal::d128;
 use crate::units::Unit;
@@ -65,6 +66,17 @@ 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),
+    };
+    return write!(f, "{}", output);
+  }
+}
 
 #[derive(Clone, Debug)]
 /// Math operators like [`Multiply`](Operator::Multiply), parentheses, etc.

src/main.rs

@@ -14,7 +14,7 @@ fn main() {
     match eval(&args[1], true, Unit::Celsius, verbose) {
       Ok(answer) => {
         if !verbose {
-          println!("{} {:?}", answer.value, answer.unit)
+          println!("{}", answer);
         }
       },
       Err(e) => {