Put lexer into it's own file

Cargo.toml

@@ -5,8 +5,5 @@ authors = ["Kasper <kasperkh.kh@gmail.com>"]
 edition = "2018"
 
 [dependencies]
-# logos = "0.9.7"
-# num-traits = "0.2"
-# num-rational = "0.2"
 nom = "5.0"
 decimal = "2.0.4"

src/lexer.rs

@@ -0,0 +1,59 @@
+use std::str::FromStr;
+use decimal::d128;
+use crate::{Token, TokenVector, Operator::*};
+
+pub fn lex(input: &str) -> Result<TokenVector, String> {
+
+  let mut chars = input.chars().enumerate().peekable();
+  let mut tokens: TokenVector = vec![];
+  
+  while let Some((index, current_char)) = chars.next() {
+    match current_char {
+      '+' => tokens.push(Token::Operator(Plus)),
+      '-' => tokens.push(Token::Operator(Minus)),
+      '*' => tokens.push(Token::Operator(Multiply)),
+      '/' => tokens.push(Token::Operator(Divide)),
+      '%' => tokens.push(Token::Operator(PercentOrModulo)),
+      '^' => tokens.push(Token::Operator(Caret)),
+      '!' => tokens.push(Token::Operator(Factorial)),
+      '(' => tokens.push(Token::Operator(LeftParen)),
+      ')' => tokens.push(Token::Operator(RightParen)),
+      ',' => continue,
+      value if value.is_whitespace() => continue,
+      value if value.is_alphabetic() => {
+
+      },
+      '.' | '0'..='9' => {
+
+        let start_index = index;
+        let mut end_index = index+1;
+        while let Some((_idk, current_char)) = chars.peek() {
+          if current_char == &'.' || current_char.is_digit(10) {
+            chars.next();
+            end_index += 1;
+          } else {
+            break;
+          }
+        }
+        
+        match d128::from_str(&input[start_index..end_index]) {
+          Ok(number) => {
+            if d128::get_status().is_empty() {
+              tokens.push(Token::Number(number));
+            } else {
+              return Err(format!("Error parsing d128 number: {}", &input[start_index..end_index]));
+            }
+          },
+          Err(_e) => {
+            return Err("Error parsing d128 number (This should not happen because d128 does not throw errors)".to_owned());
+          }
+        };
+
+      },
+      _ => {
+        return Err(format!("Unknown character: {}", current_char));
+      },
+    }
+  };
+  return Ok(tokens)
+}

src/main.rs

@@ -1,9 +1,8 @@
 use std::time::{Instant};
 use decimal::d128;
-use std::str::FromStr;
 
 #[derive(Debug)]
-enum Operator {
+pub enum Operator {
   Plus,
   Minus,
   Multiply,
@@ -14,71 +13,16 @@ enum Operator {
   LeftParen,
   RightParen,
 }
-use Operator::*;
 
 #[derive(Debug)]
-enum Token {
+pub enum Token {
   Operator(Operator),
   Number(d128),
 }
 
-type TokenVector = Vec<Token>;
+pub type TokenVector = Vec<Token>;
 
-fn lex(input: &str) -> Result<TokenVector, String> {
-
-  let mut chars = input.chars().enumerate().peekable();
-  let mut tokens: TokenVector = vec![];
-  
-  while let Some((index, current_char)) = chars.next() {
-    match current_char {
-      '+' => tokens.push(Token::Operator(Plus)),
-      '-' => tokens.push(Token::Operator(Minus)),
-      '*' => tokens.push(Token::Operator(Multiply)),
-      '/' => tokens.push(Token::Operator(Divide)),
-      '%' => tokens.push(Token::Operator(PercentOrModulo)),
-      '^' => tokens.push(Token::Operator(Caret)),
-      '!' => tokens.push(Token::Operator(Factorial)),
-      '(' => tokens.push(Token::Operator(LeftParen)),
-      ')' => tokens.push(Token::Operator(RightParen)),
-      ',' => continue,
-      value if value.is_whitespace() => continue,
-      value if value.is_alphabetic() => {
-
-      },
-      '.' | '0'..='9' => {
-
-        let start_index = index;
-        let mut end_index = index+1;
-        while let Some((_idk, current_char)) = chars.peek() {
-          if current_char == &'.' || current_char.is_digit(10) {
-            chars.next();
-            end_index += 1;
-          } else {
-            break;
-          }
-        }
-        
-        match d128::from_str(&input[start_index..end_index]) {
-          Ok(number) => {
-            if d128::get_status().is_empty() {
-              tokens.push(Token::Number(number));
-            } else {
-              return Err(format!("Error parsing d128 number: {}", &input[start_index..end_index]));
-            }
-          },
-          Err(_e) => {
-            return Err("Error parsing d128 number (This should not happen because d128 does not throw errors)".to_owned());
-          }
-        };
-
-      },
-      _ => {
-        return Err(format!("Unknown character: {}", current_char));
-      },
-    }
-  };
-  return Ok(tokens)
-}
+mod lexer;
 
 fn main() {
   let now = Instant::now();
@@ -87,7 +31,7 @@ fn main() {
   let args: Vec<String> = env::args().collect();
   let s = if args.len() == 2 { &args[1] } else { "0.1" };
 
-  match lex(s) {
+  match lexer::lex(s) {
     Ok(vector) => println!("{:?}", vector),
     Err(e) => println!("lexing error: {}", e),
   }