Added "degree" keyword with option to choose which unit that is

src/lexer.rs

@@ -7,9 +7,10 @@ use crate::TextOperator::{Of, To};
 use crate::Constant::{E, Pi};
 use crate::LexerKeyword::{In, PercentChar, Per, Mercury, Hg, PoundForce, PoundWord, Force, DoubleQuotes};
 use crate::FunctionIdentifier::{Cbrt, Ceil, Cos, Exp, Abs, Floor, Ln, Log, Round, Sin, Sqrt, Tan};
+use crate::units::Unit;
 use crate::units::Unit::*;
 
-pub fn lex(input: &str, allow_trailing_operators: bool) -> Result<TokenVector, String> {
+pub fn lex(input: &str, allow_trailing_operators: bool, default_degree: Unit) -> Result<TokenVector, String> {
 
   let mut input = input.replace(",", ""); // ignore commas
 
@@ -25,7 +26,7 @@ pub fn lex(input: &str, allow_trailing_operators: bool) -> Result<TokenVector, S
   let mut chars = input.chars().peekable();
   let mut tokens: TokenVector = vec![];
   let max_word_length = 30;
-  
+
   let mut left_paren_count = 0;
   let mut right_paren_count = 0;
 
@@ -321,6 +322,7 @@ pub fn lex(input: &str, allow_trailing_operators: bool) -> Result<TokenVector, S
             "k" | "kelvin" | "kelvins" => tokens.push(Token::Unit(Kelvin)),
             "c" | "celcius" => tokens.push(Token::Unit(Celcius)),
             "f" | "fahrenheit" | "fahrenheits" => tokens.push(Token::Unit(Fahrenheit)),
+            "deg" | "degree" | "degrees" => tokens.push(Token::Unit(default_degree)),
 
             _ => {
               return Err(format!("Invalid string: {}", string));

src/main.rs

@@ -1,3 +1,4 @@
+use crate::units::Unit;
 use std::time::{Instant};
 use decimal::d128;
 
@@ -91,17 +92,17 @@ fn main() {
   use std::env;
   let args: Vec<String> = env::args().collect();
   if args.len() >= 2 {
-    eval(&args[1], true);
+    eval(&args[1], true, Unit::Celcius);
   } else {
     println!("No argument supplied");
   }
 }
 
-pub fn eval(input: &str, allow_trailing_operators: bool) {
+pub fn eval(input: &str, allow_trailing_operators: bool, default_degree: Unit) {
 
   let lex_start = Instant::now();
-  
-  match lexer::lex(input, allow_trailing_operators) {
+
+  match lexer::lex(input, allow_trailing_operators, default_degree) {
     Ok(tokens) => {
       let lex_time = Instant::now().duration_since(lex_start).as_nanos() as f32;