From f37b73df5d57232daec09e8aba126d292ada45f1 Mon Sep 17 00:00:00 2001
From: NerdyPepper <akshayoppiliappan@gmail.com>
Date: Mon, 18 Mar 2019 21:59:05 +0530
Subject: new operator struct, updated lexer

---
 src/main.rs | 68 ++++++++++++++++++++++++++++++++-----------------------------
 1 file changed, 36 insertions(+), 32 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 6a97d1c..c91b662 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,44 +1,41 @@
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub struct Operator {
+    token: char,
+    operation: fn(f64, f64) -> f64,
+    precedence: u8,
+    is_left_associative: bool,
+}
+
 #[derive(Debug)]
 pub enum Token {
-    Operator(char),
+    Operator(Operator),
     Num(f64),
     LParen,
     RParen
 }
 
-#[derive(Debug)]
-pub struct Node {
-    value: Option<Token>,
-    left: Box<Option<Node>>,
-    right: Box<Option<Node>>
-}
-
-impl Node {
-    fn new() -> Node {
-        Node {
-            value: None,
-            left: Box::new(None),
-            right: Box::new(None)
-        }
-    }
-    fn set_val(&mut self, val: Token) {
-        self.value = Some(val);
-    }
-    fn set_left(&mut self, val: Node) {
-        self.left = Box::new(Some(val));
+impl Operator {
+    fn token_from_op(token: char, operation: fn(f64, f64) -> f64, precedence: u8, is_left_associative: bool) -> Token {
+        Token::Operator(
+            Operator {
+                token,
+                operation,
+                precedence,
+                is_left_associative
+            }
+        )
     }
-    fn set_right(&mut self, val: Node) {
-        self.right = Box::new(Some(val));
+    fn operate(self, x: f64, y: f64) -> f64 {
+        (self.operation)(x, y)
     }
 }
 
 fn main() {
-    let input = "11 + (1 + 2(3))";
+    let input = "1(2)";
     let input = input.replace(" ", "");
-
     let lexed = lexer(&input);
-
     println!("{:?}", lexed);
+    println!("{}", lexed.unwrap().len());
 }
 
 fn lexer(input: &str) -> Result<Vec<Token>, String> {
@@ -57,18 +54,26 @@ fn lexer(input: &str) -> Result<Vec<Token>, String> {
                     num_vec.clear();
                 }
                 // finish
-                result.push(Token::Operator(letter));
+                let operator_token: Token = match letter {
+                    '+' => Operator::token_from_op('+', |x, y| x + y, 2, true),
+                    '-' => Operator::token_from_op('-', |x, y| x - y, 2, true),
+                    '/' => Operator::token_from_op('/', |x, y| x / y, 3, true),
+                    '*' => Operator::token_from_op('*', |x, y| x * y, 3, true),
+                    '^' => Operator::token_from_op('^', |x, y| x.powf(y), 4, false),
+                    _ => panic!("unexpected op whuuu"),
+                };
+                result.push(operator_token);
             },
             '('  => {
                 // parse num buf
                 let parse_num = num_vec.parse::<f64>().ok();
                 if let Some(x) = parse_num {
                     result.push(Token::Num(x));
-                    result.push(Token::Operator('*'));
+                    result.push(Operator::token_from_op('*', |x, y| x * y, 3, true));
                     num_vec.clear();
                 }
                 // finish
-                result.push(Token::RParen);
+                result.push(Token::LParen);
             },
             ')' => {
                 // parse num buf
@@ -78,8 +83,9 @@ fn lexer(input: &str) -> Result<Vec<Token>, String> {
                     num_vec.clear();
                 }
                 // finish
-                result.push(Token::LParen);
+                result.push(Token::RParen);
             }
+            ' ' => {}
             _ => {
                 return Err(format!("Unexpected character: {}", letter))
             }
@@ -87,5 +93,3 @@ fn lexer(input: &str) -> Result<Vec<Token>, String> {
     }
     Ok(result)
 }
-
-
-- 
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