rustfmt and fix clippy warnings

src/day7.rs

@@ -1,23 +1,25 @@
 extern crate regex;
 
+use std::collections::HashMap;
 use std::error::Error;
+use std::fmt;
 use std::fs::File;
 use std::io::{BufRead, BufReader};
-use std::fmt;
-use std::collections::HashMap;
 
-use regex::{Regex, Captures};
+use regex::{Captures, Regex};
 
 const INPUT: &str = "inputs/7.txt";
 
 #[derive(Debug, Clone, PartialEq)]
 struct MalformedInstruction {
-    details: String
+    details: String,
 }
 
 impl MalformedInstruction {
     fn new(msg: &str) -> MalformedInstruction {
-        MalformedInstruction{ details: msg.to_string() }
+        MalformedInstruction {
+            details: msg.to_string(),
+        }
     }
 }
 
@@ -43,21 +45,26 @@ fn read_instructions(filename: &str) -> Result<HashMap<String, Vec<String>>, Box
     lazy_static! {
         static ref INSTRUCTION_REGEX: Regex = Regex::new(
             r"Step (?P<dependency>\w) must be finished before step (?P<step>\w) can begin."
-        ).unwrap();
+        )
+        .unwrap();
     }
     let file = File::open(filename)?;
-    for (index, line) in BufReader::new(file).lines().enumerate() {
+    for line in BufReader::new(file).lines() {
         match INSTRUCTION_REGEX.captures(&line?) {
             Some(captures) => {
                 let step = get_captured_field(&captures, "step")?.parse()?;
                 let dependency: String = get_captured_field(&captures, "dependency")?.parse()?;
-                instructions.entry(dependency.clone()).or_insert(Vec::new());
-                let dependencies = instructions.entry(step).or_insert(Vec::new());
+                instructions
+                    .entry(dependency.clone())
+                    .or_insert_with(Vec::new);
+                let dependencies = instructions.entry(step).or_insert_with(Vec::new);
                 dependencies.push(dependency);
-            },
-            None => return Err(Box::new(MalformedInstruction {
-                details: "Malformed instruction line, no fields could be found".to_string()
-            })),
+            }
+            None => {
+                return Err(Box::new(MalformedInstruction {
+                    details: "Malformed instruction line, no fields could be found".to_string(),
+                }))
+            }
         };
     }
     Ok(instructions)
@@ -66,9 +73,12 @@ fn read_instructions(filename: &str) -> Result<HashMap<String, Vec<String>>, Box
 fn get_captured_field(captures: &Captures, field: &str) -> Result<String, Box<Error>> {
     match captures.name(field) {
         Some(capture) => Ok(String::from(capture.as_str())),
-        None => return Err(Box::new(MalformedInstruction {
-            details: format!("Malformed instruction line, field {} could not be found", field)
-        }))
+        None => Err(Box::new(MalformedInstruction {
+            details: format!(
+                "Malformed instruction line, field {} could not be found",
+                field
+            ),
+        })),
     }
 }
 
@@ -77,18 +87,19 @@ fn get_step_sequence(instructions: &mut HashMap<String, Vec<String>>) -> String
     loop {
         let mut available: Vec<String> = instructions
             .iter()
-            .filter(|(_, dependencies)| dependencies.len() == 0)
+            .filter(|(_, dependencies)| dependencies.is_empty())
             .map(|(step, _)| step.clone())
             .collect();
-        if available.len() == 0 { break; }
+        if available.is_empty() {
+            break;
+        }
         available.sort();
         available.reverse();
         let next = available.pop().unwrap();
         instructions.remove(&next);
         for dependencies in instructions.values_mut() {
-            match dependencies.iter().position(|d| *d == next) {
-                Some(index) => { dependencies.remove(index); },
-                None => ()
+            if let Some(index) = dependencies.iter().position(|d| *d == next) {
+                dependencies.remove(index);
             }
         }
         sequence.push(next);
@@ -110,9 +121,14 @@ mod tests {
             ("C".to_string(), vec![]),
             ("B".to_string(), vec!["A".to_string()]),
             ("D".to_string(), vec!["A".to_string()]),
-            ("E".to_string(), vec!["B".to_string(), "D".to_string(), "F".to_string()]),
-
-        ].iter().cloned().collect();
+            (
+                "E".to_string(),
+                vec!["B".to_string(), "D".to_string(), "F".to_string()],
+            ),
+        ]
+        .iter()
+        .cloned()
+        .collect();
         assert_eq!(read_instructions(TEST_INPUT).unwrap(), expected);
     }
 
@@ -124,9 +140,14 @@ mod tests {
             ("C".to_string(), vec![]),
             ("B".to_string(), vec!["A".to_string()]),
             ("D".to_string(), vec!["A".to_string()]),
-            ("E".to_string(), vec!["B".to_string(), "D".to_string(), "F".to_string()]),
-
-        ].iter().cloned().collect();
+            (
+                "E".to_string(),
+                vec!["B".to_string(), "D".to_string(), "F".to_string()],
+            ),
+        ]
+        .iter()
+        .cloned()
+        .collect();
         assert_eq!(get_step_sequence(&mut instructions), "CABDFE");
     }
 }

src/main.rs

@@ -1,3 +1,5 @@
+#![warn(clippy)]
+
 #[macro_use]
 extern crate lazy_static;