aboutsummaryrefslogtreecommitdiff
path: root/docs/pages/2-define-a-dispatcher.md
diff options
context:
space:
mode:
Diffstat (limited to 'docs/pages/2-define-a-dispatcher.md')
-rw-r--r--docs/pages/2-define-a-dispatcher.md103
1 files changed, 103 insertions, 0 deletions
diff --git a/docs/pages/2-define-a-dispatcher.md b/docs/pages/2-define-a-dispatcher.md
new file mode 100644
index 0000000..804ad1b
--- /dev/null
+++ b/docs/pages/2-define-a-dispatcher.md
@@ -0,0 +1,103 @@
+<h1 align="center">Declare a Dispatcher</h1>
+<p align="center">
+ Use the <code>dispatcher!</code> macro to declare commands and register them
+</p>
+
+Mingling's pipeline starts with a Dispatcher.
+
+Its job is simple: **match the user's input command, wrap the arguments into an Entry type**.
+
+## The `dispatcher!` Macro
+
+The `dispatcher!` macro generates two types at once:
+
+| Generated type | Purpose |
+| -------------- | -------------------------------------------------------------- |
+| `CMDType` | The dispatcher itself, needs to be registered to Program |
+| `EntryType` | The entry type, wraps `Vec<String>`, serves as input for Chain |
+
+The syntax is a fixed three-part pattern:
+
+```rust
+dispatcher!("command path", DispatcherType => EntryType);
+```
+
+Here's a concrete example:
+
+```rust
+dispatcher!("greet", CMDGreet => EntryGreet);
+```
+
+> [!NOTE]
+> The command name (`"greet"`) is auto-converted to kebab-case. Even if you write `"GreetUser"`, matching will use `greet-user`.
+
+## Registering with Program
+
+Once you have a dispatcher, you need to tell Program about it:
+
+```rust
+@@@ dispatcher!("greet", CMDGreet => EntryGreet);
+@@@ fn main() {
+@@@ let mut program = ThisProgram::new();
+// Register the dispatcher
+program.with_dispatcher(CMDGreet);
+@@@ }
+@@@ gen_program!();
+```
+
+> [!TIP]
+> If you have many commands, use `with_dispatchers` to register multiple at once: `program.with_dispatchers((CMDGreet, CMDAdd, CMDRemoteRm))`.
+
+## Multi-level Commands
+
+If your program has a hierarchy — e.g., `remote add`, `remote rm` — just separate the command name with dots:
+
+```rust
+dispatcher!("remote.add", CMDRemoteAdd => EntryRemoteAdd);
+dispatcher!("remote.rm", CMDRemoteRm => EntryRemoteRm);
+```
+
+When the user types `remote add` in the terminal, Mingling matches `remote` and `add` as two levels in sequence.
+
+## The Entry Type `EntryGreet`
+
+You might be curious about what's inside `EntryGreet`. It's essentially a struct wrapping `Vec<String>`:
+
+```rust
+// Illustration of code generated by the dispatcher! macro
+pub struct EntryGreet {
+ pub inner: Vec<String>,
+}
+```
+
+When the user types `greet Alice Bob` on the command line, `EntryGreet.inner` becomes `vec!["Alice", "Bob"]`.
+
+> [!IMPORTANT]
+> Entry's `inner` only contains **the remaining args after matching**.
+>
+> Take `remote add origin` as an example: `remote` and `add` are used for matching the command path, only `origin` goes into `EntryRemoteAdd.inner`.
+
+## Advanced: Implicit Declaration
+
+The above is the standard syntax. If you enable the `extra_macros` feature, you can be more concise:
+
+```rust
+// Features: ["extra_macros"]
+// Omit CMDType and EntryType, names are auto-derived
+ dispatcher!("greet");
+// dispatcher!("greet", CMDGreet => EntryGreet);
+```
+
+This syntax auto-generates `CMDGreet` and `EntryGreet`, with the same effect as the explicit declaration.
+
+But for the tutorial, we'll stick with explicit syntax — it's clearer and doesn't require extra features.
+
+See [Feature List](pages/other/features) for details.
+
+## Next Step
+
+Next we'll write a Chain to receive the Entry and handle the actual business logic.
+
+<p align="center" style="font-size: 0.85em; color: gray;">
+ Written by @Weicao-CatilGrass
+</p>