use 2018 edition and minor refactors

Cargo.toml

@@ -37,6 +37,7 @@ categories = ["command-line-interface"]
 description = """
 A simple to use, efficient, and full-featured Command Line Argument Parser
 """
+edition = "2018"
 
 [badges]
 travis-ci = { repository = "clap-rs/clap" }

src/build/app/mod.rs

@@ -1378,7 +1378,7 @@ impl<'b> App<'b> {
         T: Into<OsString> + Clone,
     {
         debugln!("App::_do_parse;");
-        let mut matcher = ArgMatcher::new();
+        let mut matcher = ArgMatcher::default();
 
         // If there are global arguments, or settings we need to propgate them down to subcommands
         // before parsing incase we run into a subcommand

src/build/app/settings.rs

@@ -2,6 +2,7 @@
 #[allow(unused_imports)]
 use std::ops::BitOr;
 use std::str::FromStr;
+use bitflags::bitflags;
 
 bitflags! {
     struct Flags: u64 {

src/build/arg/settings.rs

@@ -1,6 +1,8 @@
 // Std
 use std::str::FromStr;
 
+use bitflags::bitflags;
+
 bitflags! {
     struct Flags: u32 {
         const REQUIRED         = 1;

src/lib.rs

@@ -45,7 +45,6 @@
 //! // This example demonstrates clap's full 'builder pattern' style of creating arguments which is
 //! // more verbose, but allows easier editing, and at times more advanced options, or the possibility
 //! // to generate arguments dynamically.
-//! extern crate clap;
 //! use clap::{Arg, App, };
 //!
 //! fn main() {
@@ -116,7 +115,6 @@
 //! //
 //! // This example demonstrates clap's "usage strings" method of creating arguments
 //! // which is less verbose
-//! extern crate clap;
 //! use clap::{Arg, App, };
 //!
 //! fn main() {
@@ -189,7 +187,6 @@
 //! // This example demonstrates clap's building from YAML style of creating arguments which is far
 //! // more clean, but takes a very small performance hit compared to the other two methods.
 //! #[macro_use]
-//! extern crate clap;
 //! use clap::App;
 //!
 //! fn main() {
@@ -205,8 +202,6 @@
 //! builder pattern (the first example), but without all the verbosity.
 //!
 //! ```no_run
-//! #[macro_use]
-//! extern crate clap;
 //!
 //! fn main() {
 //!     let matches = clap_app!(myapp =>
@@ -285,7 +280,6 @@
 //! * Add the following to your `src/main.rs`
 //!
 //! ```no_run
-//! extern crate clap;
 //! use clap::App;
 //!
 //! fn main() {
@@ -315,8 +309,6 @@
 //! git = "https://github.com/kbknapp/clap-rs.git"
 //! ```
 //!
-//! Add `extern crate clap;` to your crate root.
-//!
 //! Define a list of valid arguments for your program (see the
 //! [documentation](https://docs.rs/clap/) or [examples/] directory of this repo)
 //!
@@ -534,28 +526,6 @@
 // #![cfg_attr(feature = "lints", allow(doc_markdown))]
 // #![cfg_attr(feature = "lints", allow(explicit_iter_loop))]
 
-#[cfg(all(feature = "color", not(target_os = "windows")))]
-extern crate ansi_term;
-#[cfg(feature = "color")]
-extern crate atty;
-#[macro_use]
-extern crate bitflags;
-#[cfg(feature = "derive")]
-#[cfg_attr(feature = "derive", allow(unused_imports))]
-#[cfg_attr(feature = "derive", macro_use)]
-extern crate clap_derive;
-extern crate indexmap;
-#[cfg(feature = "suggestions")]
-extern crate strsim;
-#[cfg(feature = "wrap_help")]
-extern crate term_size;
-extern crate textwrap;
-extern crate unicode_width;
-#[cfg(feature = "vec_map")]
-extern crate vec_map;
-#[cfg(feature = "yaml")]
-extern crate yaml_rust;
-
 pub use crate::build::{App, AppSettings, Arg, ArgGroup, ArgSettings, Propagation};
 pub use crate::output::fmt::Format;
 pub use crate::parse::errors::{Error, ErrorKind, Result};

src/mkeymap.rs

@@ -99,29 +99,24 @@ impl<'b> MKeyMap<'b> {
     //TODO ::get_first([KeyA, KeyB])
 
     pub fn get_mut(&mut self, key: &KeyType) -> Option<&mut Arg<'b>> {
-        for k in &self.keys {
-            if &k.key == key {
-                return self.args.get_mut(k.index);
-            }
-        }
-        None
+        let key = self.keys.iter()
+        .find(|k| k.key == *key);
+
+        match key {
+            Some(k) => self.args.get_mut(k.index),
+            None => None
     }
+    }
+
 
     pub fn is_empty(&self) -> bool { self.keys.is_empty() && self.args.is_empty() }
 
     pub fn remove_key(&mut self, key: &KeyType) {
-        let mut idx = None;
-        for (i, k) in self.keys.iter().enumerate() {
-            if &k.key == key {
-                idx = Some(i);
-                break;
-            }
-        }
-        if let Some(idx) = idx {
-            self.keys.swap_remove(idx);
+        let idx = self.keys.iter().enumerate().find(|(_,k)| k.key == *key).and_then(|(i, _)| Some(i));
+        if let Some(id) = idx {
+            self.keys.swap_remove(id);
         }
     }
-    //TODO ::remove_keys([KeyA, KeyB])
 
     pub fn insert_key_by_name(&mut self, key: KeyType, name: &str) {
         let index = self.find_by_name(name);

src/parse/arg_matcher.rs

@@ -2,6 +2,7 @@
 use std::collections::HashMap;
 use std::ffi::OsStr;
 use std::mem;
+use std::ops::Deref;
 
 // Third Party
 use indexmap;
@@ -20,8 +21,14 @@ impl Default for ArgMatcher {
     fn default() -> Self { ArgMatcher(ArgMatches::default()) }
 }
 
+impl Deref for ArgMatcher {
+    type Target = ArgMatches;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
 impl ArgMatcher {
-    pub fn new() -> Self { ArgMatcher::default() }
 
     pub fn into_inner(self) -> ArgMatches { self.0 }
 

src/parse/parser.rs

@@ -623,7 +623,7 @@ where
                 };
 
                 // Collect the external subcommand args
-                let mut sc_m = ArgMatcher::new();
+                let mut sc_m = ArgMatcher::default();
                 while let Some(v) = it.next() {
                     let a = v.into();
                     if a.to_str().is_none() && !self.is_set(AS::StrictUtf8) {
@@ -888,7 +888,7 @@ where
             self.app._propagate(Propagation::To(id));
         }
         if let Some(sc) = subcommands_mut!(self.app).find(|s| s.name == sc_name) {
-            let mut sc_matcher = ArgMatcher::new();
+            let mut sc_matcher = ArgMatcher::default();
             // bin_name should be parent's bin_name + [<reqs>] + the sc's name separated by
             // a space
             sc.usage = Some(format!(