add support for dashed arg names and values in arg! macro

src/macros.rs

@@ -512,6 +512,32 @@ macro_rules! arg_impl {
             $($tail)*
         }
     };
+    (
+        @arg
+        ($arg:expr)
+        <$value_name:literal>
+        $($tail:tt)*
+    ) => {
+        $crate::arg_impl! {
+            @arg
+            ({
+                debug_assert!(!$arg.is_multiple_occurrences_set(), "Values should precede `...`");
+                debug_assert_eq!($arg.get_value_names(), None, "Multiple values not yet supported");
+
+                let mut arg = $arg;
+
+                arg = arg.required(true);
+                arg = arg.takes_value(true);
+
+                let value_name = $crate::arg_impl! { @string $value_name };
+                if arg.get_id().is_empty() {
+                    arg = arg.id(value_name);
+                }
+                arg.value_name(value_name)
+            })
+            $($tail)*
+        }
+    };
     (
         @arg
         ($arg:expr)
@@ -542,6 +568,36 @@ macro_rules! arg_impl {
             $($tail)*
         }
     };
+    (
+        @arg
+        ($arg:expr)
+        [$value_name:literal]
+        $($tail:tt)*
+    ) => {
+        $crate::arg_impl! {
+            @arg
+            ({
+                debug_assert!(!$arg.is_multiple_occurrences_set(), "Values should precede `...`");
+                debug_assert_eq!($arg.get_value_names(), None, "Multiple values not yet supported");
+
+                let mut arg = $arg;
+
+                if arg.get_long().is_none() && arg.get_short().is_none() {
+                    arg = arg.required(false);
+                } else {
+                    arg = arg.min_values(0).max_values(1);
+                }
+                arg = arg.takes_value(true);
+
+                let value_name = $crate::arg_impl! { @string $value_name };
+                if arg.get_id().is_empty() {
+                    arg = arg.id(value_name);
+                }
+                arg.value_name(value_name)
+            })
+            $($tail)*
+        }
+    };
     (
         @arg
         ($arg:expr)

tests/builder/arg_name.rs

@@ -0,0 +1,14 @@
+use clap::{arg, Arg, Command};
+
+#[test]
+fn arg_name_dashed() {
+    let arg = arg!(["some-arg"] "some arg");
+    assert_eq!(arg, Arg::new("some-arg").help("some arg"));
+
+    let m = Command::new("flag")
+        .arg(arg)
+        .try_get_matches_from(vec!["", "some-val"])
+        .unwrap();
+    assert!(m.is_present("some-arg"));
+    assert_eq!(m.value_of("some-arg").unwrap(), "some-val");
+}

tests/builder/arg_value.rs

@@ -0,0 +1,39 @@
+use clap::{arg, Arg, Command};
+
+#[test]
+fn arg_value_dashed_with_short() {
+    let arg = arg!(-a <"some-val"> "some arg");
+    assert_eq!(
+        arg,
+        Arg::new("some-val")
+            .short('a')
+            .long("arg")
+            .value_name("some-val")
+    );
+
+    let m = Command::new("cmd")
+        .arg(arg)
+        .try_get_matches_from(vec!["", "-a", "val"])
+        .unwrap();
+    assert!(m.is_present("some-val"));
+    assert_eq!(m.value_of("some-val").unwrap(), "val");
+}
+
+#[test]
+fn arg_value_dashed_with_long() {
+    let arg = arg!(-a --arg <"some-val"> "some arg");
+    assert_eq!(
+        arg,
+        Arg::new("arg")
+            .short('a')
+            .long("arg")
+            .value_name("some-val")
+    );
+
+    let m = Command::new("cmd")
+        .arg(arg)
+        .try_get_matches_from(vec!["", "--arg", "some-val"])
+        .unwrap();
+    assert!(m.is_present("arg"));
+    assert_eq!(m.value_of("arg").unwrap(), "some-val");
+}

tests/builder/main.rs

@@ -3,7 +3,9 @@ mod app_settings;
 mod arg_aliases;
 mod arg_aliases_short;
 mod arg_matcher_assertions;
+mod arg_name;
 mod arg_settings;
+mod arg_value;
 mod borrowed;
 mod cargo;
 mod command;