3 files changed, 99 insertions, 1 deletions

diff --git a/arg_picker/src/constants.rs b/arg_picker/src/constants.rs
new file mode 100644
index 0000000..39250f8
--- /dev/null
+++ b/arg_picker/src/constants.rs
@@ -0,0 +1,16 @@
+use std::marker::PhantomData;
+
+use crate::{PickerArg, PickerArgs};
+
+/// Remaining positional arguments (anything not consumed as an option).
+/// - `full`: `[]` (empty — not triggered by any `--` prefix).
+/// - `short`: (none)
+/// - `positional`: `false` (this is a meta‑argument that collects everything left).
+///   This constant is used internally to access any leftover arguments after
+///   all defined flags/options have been processed.
+pub const REMAINS: PickerArg<PickerArgs> = PickerArg::<PickerArgs> {
+    full: &[],
+    short: None,
+    positional: false,
+    internal_type: PhantomData,
+};
diff --git a/arg_picker/src/lib.rs b/arg_picker/src/lib.rs
index c65e793..285cd16 100644
--- a/arg_picker/src/lib.rs
+++ b/arg_picker/src/lib.rs
@@ -48,3 +48,13 @@ pub mod matcher_needed {
     pub use crate::PickerArgInfo;
     pub use crate::parselib::{MaskedArg, Matcher, ParserStyle};
 }
+
+mod constants;
+
+/// Re-export of constants used by `arg-picker`.
+///
+/// This module provides access to various constants defined internally, such as
+/// default values, configuration limits, and other static parameters.
+pub mod consts {
+    pub use crate::constants::*;
+}
diff --git a/arg_picker/src/picker.rs b/arg_picker/src/picker.rs
index f31a5b6..f722fb5 100644
--- a/arg_picker/src/picker.rs
+++ b/arg_picker/src/picker.rs
@@ -369,11 +369,83 @@ pub trait IntoPicker<'a> {
     fn pick<N>(self, arg: impl Into<&'a PickerArg<'a, N>>) -> PickerPattern1<'a, N, ()>
     where
         Self: Sized,
-        N: Pickable<'a> + Default + Sized,
+        N: Pickable<'a> + Sized,
     {
         Picker::build_pattern1(self.to_picker().args, arg.into(), None::<()>)
     }
 
+    /// Starts building a picker pattern with the first argument, using a default value provider.
+    ///
+    /// This is a shorthand for calling `.pick(arg).or(func)`.
+    ///
+    /// # Type Parameters
+    ///
+    /// * `Next` — The nominal type of the first argument; must implement [`Pickable`].
+    ///
+    /// # Parameters
+    ///
+    /// * `arg` — The argument definition, typically obtained from [`crate::macros::arg`].
+    /// * `func` — A closure that provides a default value if the arg is not provided by the user.
+    fn pick_or<Next, F>(
+        self,
+        arg: impl Into<&'a PickerArg<'a, Next>>,
+        func: F,
+    ) -> PickerPattern1<'a, Next, ()>
+    where
+        Self: Sized,
+        Next: Pickable<'a> + Sized,
+        F: FnMut() -> Next + 'static,
+    {
+        self.pick(arg).or(func)
+    }
+
+    /// Starts building a picker pattern with the first argument, using a default value.
+    ///
+    /// This is a shorthand for calling `.pick(arg).or_default()`.
+    ///
+    /// # Type Parameters
+    ///
+    /// * `Next` — The nominal type of the first argument; must implement [`Pickable`] and [`Default`].
+    ///
+    /// # Parameters
+    ///
+    /// * `arg` — The argument definition, typically obtained from [`crate::macros::arg`].
+    fn pick_or_default<Next>(
+        self,
+        arg: impl Into<&'a PickerArg<'a, Next>>,
+    ) -> PickerPattern1<'a, Next, ()>
+    where
+        Self: Sized,
+        Next: Pickable<'a> + Default + Sized,
+    {
+        self.pick(arg).or_default()
+    }
+
+    /// Starts building a picker pattern with the first argument, using a route if the arg is not provided.
+    ///
+    /// This is a shorthand for calling `.pick(arg).or_route(func)`.
+    ///
+    /// # Type Parameters
+    ///
+    /// * `Next` — The nominal type of the first argument; must implement [`Pickable`].
+    ///
+    /// # Parameters
+    ///
+    /// * `arg` — The argument definition, typically obtained from [`crate::macros::arg`].
+    /// * `func` — A closure that produces a route value if the arg is not provided by the user.
+    fn pick_or_route<Next, F, Route>(
+        self,
+        arg: impl Into<&'a PickerArg<'a, Next>>,
+        func: F,
+    ) -> PickerPattern1<'a, Next, Route>
+    where
+        Self: Sized,
+        Next: Pickable<'a> + Sized,
+        F: FnMut() -> Route + 'static,
+    {
+        self.pick(arg).with_route::<Route>().or_route(func)
+    }
+
     /// Converts the value into a `Picker` with a specified route type.
     ///
     /// This method allows changing the route (phantom type parameter) of the picker.