New feature: 'iter_matches'

Cargo.toml

@@ -33,6 +33,7 @@ clippy    = { version = "~0.0.166", optional = true }
 atty      = { version = "0.2.2",  optional = true }
 vec_map   = { version = "0.8", optional = true }
 term_size = { version = "0.3.0", optional = true }
+indexmap  = { version = "1.0.1", optional = true }
 
 [target.'cfg(not(windows))'.dependencies]
 ansi_term = { version = "0.11",  optional = true }
@@ -43,17 +44,18 @@ lazy_static = "1"
 version-sync = "0.5"
 
 [features]
-default     = ["suggestions", "color", "vec_map"]
-suggestions = ["strsim"]
-color       = ["ansi_term", "atty"]
-wrap_help   = ["term_size", "textwrap/term_size"]
-yaml        = ["yaml-rust"]
-unstable    = [] # for building with unstable clap features (doesn't require nightly Rust) (currently none)
-nightly     = [] # for building with unstable Rust features (currently none)
-lints       = ["clippy"] # Requires nightly Rust
-debug       = [] # Enables debug messages
-no_cargo    = [] # Enable if you're not using Cargo, disables Cargo-env-var-dependent macros
-doc         = ["yaml"] # All the features which add to documentation
+default      = ["suggestions", "color", "vec_map"]
+suggestions  = ["strsim"]
+color        = ["ansi_term", "atty"]
+wrap_help    = ["term_size", "textwrap/term_size"]
+yaml         = ["yaml-rust"]
+iter_matches = ["indexmap"]
+unstable     = [] # for building with unstable clap features (doesn't require nightly Rust) (currently none)
+nightly      = [] # for building with unstable Rust features (currently none)
+lints        = ["clippy"] # Requires nightly Rust
+debug        = [] # Enables debug messages
+no_cargo     = [] # Enable if you're not using Cargo, disables Cargo-env-var-dependent macros
+doc          = ["yaml"] # All the features which add to documentation
 
 [profile.release]
 opt-level = 3

src/args/arg_matcher.rs

@@ -1,5 +1,7 @@
 // Std
+#[cfg(not(feature = "iter_matches"))]
 use std::collections::hash_map::{Entry, Iter};
+#[cfg(not(feature = "iter_matches"))]
 use std::collections::HashMap;
 use std::ffi::OsStr;
 use std::ops::Deref;
@@ -10,6 +12,12 @@ use args::{ArgMatches, MatchedArg, SubCommand};
 use args::AnyArg;
 use args::settings::ArgSettings;
 
+// iter_matches specific
+#[cfg(feature = "iter_matches")] extern crate indexmap;
+#[cfg(feature = "iter_matches")] use self::indexmap::map::{Entry, Iter};
+#[cfg(feature = "iter_matches")] use self::indexmap::IndexMap as HashMap;
+
+
 #[doc(hidden)]
 #[allow(missing_debug_implementations)]
 pub struct ArgMatcher<'a>(pub ArgMatches<'a>);

src/args/arg_matches.rs

@@ -1,6 +1,11 @@
+// iter_matches specific
+#[cfg(feature = "iter_matches")]
+use indexmap::IndexMap as HashMap;
+
 // Std
-use std::borrow::Cow;
+#[cfg(not(feature = "iter_matches"))]
 use std::collections::HashMap;
+use std::borrow::Cow;
 use std::ffi::{OsStr, OsString};
 use std::iter::Map;
 use std::slice::Iter;

src/lib.rs

@@ -536,6 +536,8 @@ extern crate atty;
 extern crate bitflags;
 #[cfg(feature = "suggestions")]
 extern crate strsim;
+#[cfg(feature = "iter_matches")]
+extern crate indexmap;
 #[cfg(feature = "wrap_help")]
 extern crate term_size;
 extern crate textwrap;

tests/iter_matches.rs

@@ -0,0 +1,15 @@
+extern crate clap;
+
+use clap::{App, Arg};
+
+#![cfg(feature = "iter_matches")]
+#[test]
+fn iter_matches_empty() {
+    let res = App::new("prog")
+        .arg(Arg::with_name("cfg")
+            .takes_value(true)
+            .long("config"))
+        .get_matches_from_safe(vec!["prog"]);
+    assert!(res.is_ok());
+    assert_eq!(res.unwrap().args.iter().count(), 0);
+}