From 36d5ff553a1d65d70da5251b8865d62294c929f6 Mon Sep 17 00:00:00 2001
From: Melody Horn <melody@boringcactus.com>
Date: Sun, 7 Mar 2021 09:12:47 -0700
Subject: tear it all up and implement super basic actors

---
 src/number.rs | 39 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

(limited to 'src/number.rs')

diff --git a/src/number.rs b/src/number.rs
index a71399c..94a67f1 100644
--- a/src/number.rs
+++ b/src/number.rs
@@ -1,7 +1,10 @@
+use std::cmp::max;
+use std::fmt::{Display, Formatter, Result as FormatResult};
+use std::ops::Add;
+
 #[derive(Clone)]
 pub struct Number {
     pub integer_part: String,
-    pub fractional_part: String,
 }
 
 macro_rules! int_conv {
@@ -10,7 +13,6 @@ macro_rules! int_conv {
             fn from(x: $t) -> Number {
                 Number {
                     integer_part: x.to_string(),
-                    fractional_part: "".to_string(),
                 }
             }
         }
@@ -18,3 +20,36 @@ macro_rules! int_conv {
 }
 
 int_conv!(u8, u16, u32, u64, usize, i8, i16, i32, i64, isize);
+
+impl Display for Number {
+    fn fmt(&self, f: &mut Formatter<'_>) -> FormatResult {
+        f.write_str(&self.integer_part)
+    }
+}
+
+impl Add for Number {
+    type Output = Number;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        let longest_ipart_len = max(self.integer_part.len(), rhs.integer_part.len());
+        let self_padded = format!("{:0>len$}", self.integer_part, len=longest_ipart_len);
+        let rhs_padded = format!("{:0>len$}", rhs.integer_part, len=longest_ipart_len);
+        let mut result_ipart_reverse = "".to_string();
+        let mut carry: u8 = 0;
+        for (self_char, rhs_char) in self_padded.chars().rev().zip(rhs_padded.chars().rev()) {
+            let self_char_val = self_char.to_digit(10).unwrap() as u8;
+            let rhs_char_val = rhs_char.to_digit(10).unwrap() as u8;
+            let sum = self_char_val + rhs_char_val + carry;
+            let sum_last_digit = (sum % 10).to_string().chars().next().unwrap();
+            carry = sum / 10;
+            result_ipart_reverse.push(sum_last_digit);
+        }
+        if carry > 0 {
+            result_ipart_reverse.push_str(&carry.to_string());
+        }
+        let result_ipart = result_ipart_reverse.chars().rev().collect();
+        Number {
+            integer_part: result_ipart,
+        }
+    }
+}
-- 
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