feat(mingling_macros, mingling_pathf): add `#[command]` attribute macro

Add a new `#[command]` attribute macro (feature-gated behind
`extra_macros`) that converts a plain function with a `Vec<String>`
parameter into a fully wired Mingling command. The macro generates a
`dispatcher!` call, a `#[chain]` wrapper, and a hidden module
re-exporting
all generated types.

Also add `CommandPattern` to the pathf pattern analyzer to recognize
`#[command]`-annotated functions and track their generated hidden
modules.

1 files changed, 81 insertions, 0 deletions

diff --git a/mingling_pathf/src/patterns/command.rs b/mingling_pathf/src/patterns/command.rs
new file mode 100644
index 0000000..fac70af
--- /dev/null
+++ b/mingling_pathf/src/patterns/command.rs
@@ -0,0 +1,81 @@
+//! The `CommandPattern` matches functions annotated with `#[command]` and
+//! extracts the generated hidden module name (`__command_<fn>_module`).
+//!
+//! Supported forms:
+//! ```rust,ignore
+//! #[command]
+//! fn greet(args: Vec<String>) -> Next { ... }
+//!
+//! #[command(node = "foo.foo-bar")]
+//! fn greet(args: Vec<String>) -> Next { ... }
+//!
+//! #[command(name = CMDGreet, entry = EntryGreet)]
+//! fn greet(args: Vec<String>) -> Next { ... }
+//!
+//! #[command(node = "greet", name = CMDGreet, entry = EntryGreet, buffer)]
+//! fn greet(args: Vec<String>) { ... }
+//! ```
+
+use syn::Item;
+
+use crate::pattern_analyzer::{AnalyzeItem, AnalyzePattern};
+
+/// Match `#[command]` functions.
+///
+/// The `#[command]` macro generates a hidden `__command_<fn>_module` that
+/// re-exports all internal types (`Entry*`, `CMD*`, chain struct, dispatcher
+/// static). This pattern tracks that module; the build system generates a
+/// glob re-export `use path::__command_<fn>_module::*;` to bring everything
+/// into scope.
+pub struct CommandPattern;
+
+impl AnalyzePattern for CommandPattern {
+    fn contains(&self, content: &str) -> bool {
+        content.contains("command")
+    }
+
+    fn analyze(&self, content: &str) -> Vec<AnalyzeItem> {
+        let Ok(syntax) = syn::parse_file(content) else {
+            return Vec::new();
+        };
+
+        let mut items = Vec::new();
+        for item in &syntax.items {
+            collect_from_item(item, "", &mut items);
+        }
+        items
+    }
+}
+
+fn collect_from_item(item: &Item, current_mod: &str, items: &mut Vec<AnalyzeItem>) {
+    match item {
+        Item::Fn(f) if has_command_attr(&f.attrs) => {
+            let fn_name = f.sig.ident.to_string();
+            let mod_name = format!("__command_{}_module", &fn_name);
+            items.push(AnalyzeItem::local_module(current_mod.to_string(), mod_name));
+        }
+        Item::Mod(item_mod) => {
+            if let Some((_, nested)) = &item_mod.content {
+                let mod_name = &item_mod.ident.to_string();
+                let nested_mod = if current_mod.is_empty() {
+                    mod_name.clone()
+                } else {
+                    format!("{current_mod}::{mod_name}")
+                };
+                for n in nested {
+                    collect_from_item(n, &nested_mod, items);
+                }
+            }
+        }
+        _ => {}
+    }
+}
+
+fn has_command_attr(attrs: &[syn::Attribute]) -> bool {
+    attrs.iter().any(|a| {
+        a.path()
+            .segments
+            .last()
+            .is_some_and(|s| s.ident == "command")
+    })
+}