Apply RustFmt and Clippy recommended changes

In order to make the CI work, we need to comply with RustFmt and Clippy
rules.

.semaphore/semaphore.yml

@@ -9,18 +9,23 @@ agent:
 blocks:
   - name: 'Default'
     task:
+      prologue:
+        commands:
+          - checkout
+          - export LOCK_CHECKSUM=$(checksum Cargo.lock)
+          - ( cd /usr/local && cache restore cargo-${SEMAPHORE_GIT_BRANCH}-${LOCK_CHECKSUM} )
       jobs:
         - name: Formatter and linter
           commands:
-            - checkout
             - rustup component add rustfmt clippy
             - cache restore clippy-${SEMAPHORE_GIT_BRANCH}-${LOCK_CHECKSUM}
             - cargo fmt --verbose --all -- --check
             - cargo clippy
-            - cache store clippy-${SEMAPHORE_GIT_BRANCH}-${LOCK_CHECKSUM}
+            - cache store clippy-${SEMAPHORE_GIT_BRANCH}-${LOCK_CHECKSUM} target
         - name: Build and tests
           commands:
-            - checkout
+            - cache restore target-${SEMAPHORE_GIT_BRANCH}-${LOCK_CHECKSUM}
             - rustup toolchain install nightly
-            - cargo build --verbose
             - cargo +nightly test --verbose
+            - ( cd /usr/local && cache store cargo-${SEMAPHORE_GIT_BRANCH}-${LOCK_CHECKSUM} cargo )
+            - cache store target-${SEMAPHORE_GIT_BRANCH}-${LOCK_CHECKSUM} target

src/bin/main.rs

@@ -1,19 +1,19 @@
 extern crate sql_lexer;
 
 use std::env;
-use std::io::prelude::*;
 use std::fs::File;
+use std::io::prelude::*;
 
 use sql_lexer::*;
 
 fn main() {
-    match env::args().skip(1).next() {
+    match env::args().nth(1) {
         Some(arg) => {
             let mut file = File::open(arg.as_str()).unwrap();
             let mut contents = String::new();
             file.read_to_string(&mut contents).unwrap();
             println!("{}", sanitize_string(contents));
-        },
-        None => println!("Please supply a path to a file containing SQL")
+        }
+        None => println!("Please supply a path to a file containing SQL"),
     }
 }