day 3, rust

03/Cargo.lock

@@ -0,0 +1,61 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "aoc2024-03"
+version = "0.1.0"
+dependencies = [
+ "peg",
+]
+
+[[package]]
+name = "peg"
+version = "0.8.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "295283b02df346d1ef66052a757869b2876ac29a6bb0ac3f5f7cd44aebe40e8f"
+dependencies = [
+ "peg-macros",
+ "peg-runtime",
+]
+
+[[package]]
+name = "peg-macros"
+version = "0.8.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bdad6a1d9cf116a059582ce415d5f5566aabcd4008646779dab7fdc2a9a9d426"
+dependencies = [
+ "peg-runtime",
+ "proc-macro2",
+ "quote",
+]
+
+[[package]]
+name = "peg-runtime"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3aeb8f54c078314c2065ee649a7241f46b9d8e418e1a9581ba0546657d7aa3a"
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.92"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37d3544b3f2748c54e147655edb5025752e2303145b5aefb3c3ea2c78b973bb0"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.37"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b5b9d34b8991d19d98081b46eacdd8eb58c6f2b201139f7c5f643cc155a633af"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "adb9e6ca4f869e1180728b7950e35922a7fc6397f7b641499e8f3ef06e50dc83"

03/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "aoc2024-03"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+peg="0.8.4"

03/src/first.rs

@@ -0,0 +1,20 @@
+peg::parser! {
+    grammar mul() for str {
+        rule number() -> u32
+            = n:$(['0'..='9']+) {? n.parse().or(Err("u32")) }
+
+        rule mul_fn() -> u32
+            = "mul(" a:number() "," b:number() ")" { a * b }
+
+        rule step() -> u32
+            = n:mul_fn() { n }
+            / [_] { 0 }
+
+        pub rule program() -> u32
+            = x:step()+ { x.iter().sum() }
+    }
+}
+
+pub fn parse(a: &str) -> u32 {
+    mul::program(a).unwrap()
+}

03/src/main.rs

@@ -0,0 +1,30 @@
+mod first;
+mod second;
+
+fn main() {
+    let raw = std::fs::read_to_string("input.txt").expect("Couldn't read input");
+    let first = first::parse(&raw);
+    println!("{}", first);
+    let second: u32 = second::parse(&raw)
+        .iter()
+        .scan(true, |p, i| match i {
+            second::Item::Do => {
+                *p = true;
+                Some(None)
+            }
+            second::Item::Dont => {
+                *p = false;
+                Some(None)
+            }
+            second::Item::Mul(n) => {
+                if *p {
+                    Some(Some(n))
+                } else {
+                    Some(None)
+                }
+            }
+        })
+        .flatten()
+        .sum();
+    println!("{}", second);
+}

03/src/second.rs

@@ -0,0 +1,34 @@
+pub enum Item {
+    Do,
+    Dont,
+    Mul(u32),
+}
+
+peg::parser! {
+    grammar mul() for str {
+        rule number() -> u32
+            = n:$(['0'..='9']+) {? n.parse().or(Err("u32")) }
+
+        rule mul_fn() -> Item
+            = "mul(" a:number() "," b:number() ")" { Item::Mul(a * b) }
+
+        rule do_fn() -> Item
+            = "do()" { Item::Do }
+
+        rule dont_fn() -> Item
+            = "don't()" { Item::Dont }
+
+        rule step() -> Option<Item>
+            = n:mul_fn() { Some(n) }
+            / n:do_fn() { Some(n) }
+            / n:dont_fn() { Some(n) }
+            / [_] { None }
+
+        pub rule program() -> Vec<Item>
+            = x:step()+ { x.into_iter().flatten().collect() }
+    }
+}
+
+pub fn parse(a: &str) -> Vec<Item> {
+    mul::program(a).unwrap()
+}