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diff --git a/docs/pages/10-help.md b/docs/pages/10-help.md new file mode 100644 index 0000000..2f3b74f --- /dev/null +++ b/docs/pages/10-help.md @@ -0,0 +1,69 @@ +<h1 align="center">Help Info</h1> +<p align="center"> + Adding --help support to commands +</p> + +A CLI without help info is not a good CLI. + +In Mingling, use the `#[help]` macro to add help text to commands. + +## Simplest Help + +Write a help function directly for an Entry: + +```rust +@@@use mingling::macros::help; +@@@dispatcher!("greet", CMDGreet => EntryGreet); +#[help] +fn help_greet(_entry: EntryGreet) { + r_println!("Usage: greet [name]"); + r_println!("Say hello to someone."); +} +``` + +> [!NOTE] +> Help functions also use `r_println!`, because `#[help]` follows the rendering pipeline — it's a short-circuit render triggered early by the `--help` flag, not logic outside the pipeline. + +## Global Help + +You can also write help for `ErrorDispatcherNotFound` as the "root help": + +```rust +@@@use mingling::macros::help; +// Triggered when user passes --help directly +#[help] +fn help_root(entry: ErrorDispatcherNotFound) { + r_println!("Usage: my-cli <command>"); + r_println!("Commands:"); + r_println!(" greet Say hello"); +} +``` + +> [!TIP] +> `ErrorDispatcherNotFound` is a type generated by `gen_program!()`, representing "no matching command found." Writing `#[help]` for it adds help to the program's root command. + +## Requires Setup + +For `--help` to work properly, add `BasicProgramSetup` in `main`: + +```rust +@@@use mingling::macros::help; +@@@use mingling::setup::BasicProgramSetup; +@@@dispatcher!("greet", CMDGreet => EntryGreet); +fn main() { + let mut program = ThisProgram::new(); + program.with_setup(BasicProgramSetup); + program.with_dispatcher(CMDGreet); + program.exec_and_exit(); +} +``` + +`BasicProgramSetup` includes `HelpFlagSetup`, which simply sets `program.user_context.help` to `true`. + +The actual routing to the `#[help]` function is handled by code generated via `gen_program!()` — it checks this flag during dispatch, and if `true`, goes through the help rendering path, bypassing the Chain. + +Without `BasicProgramSetup`, `--help` is treated as a normal argument and passed as input to the Entry's Chain. + +<p align="center" style="font-size: 0.85em; color: gray;"> + Written by @Weicao-CatilGrass +</p> |
