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diff --git a/GETTING_STARTED.md b/GETTING_STARTED.md new file mode 100644 index 0000000..e08d17b --- /dev/null +++ b/GETTING_STARTED.md @@ -0,0 +1,775 @@ +# Writing with Mingling + +## The Big Picture + +Mingling organizes your CLI program into three distinct phases: + +``` +Input → [Dispatcher] → Entry → [Chain(s)] → Result → [Renderer] → Output +``` + +**Step 1: Input** — The user's raw arguments flow in. +**Step 2: Dispatch** — The **Dispatcher** receives them and wraps them into an **Entry** type. +**Step 3: Chain** — The Entry is handed to a **Chain** function for processing. +**Step 4: Render** — The **Renderer** receives the result and writes it to the terminal. + +> [!NOTE] +> A Chain can produce a **State** type, passed to the next Chain for further processing, +> +> or it can produce a **Result** type, handed to the Renderer for output. + +Every step in this pipeline is a **pure function** annotated with an attribute macro, and the framework recognizes them as long as they meet the requirements. + +--- + +## 1. Defining Commands — `dispatcher!` + +The entry point for every subcommand is the `dispatcher!` macro. It generates two structs for you: a **Dispatcher** (used to register the command with the program) and an **Entry** (a wrapper around `Vec<String>` that holds the raw arguments). + +```rust +use mingling::prelude::*; + +// command.name Dispatcher EntryType +// │ │ │ +dispatcher!("greet", CMDGreet => EntryGreet); + +// Nested subcommand: `remote add` +dispatcher!("remote.add", CMDRemoteAdd => EntryRemoteAdd); +``` + +Then in `main()`, register the dispatcher with the program: + +```rust +dispatcher!("greet", CMDGreet => EntryGreet); + +fn main() { + let mut program = ThisProgram::new(); + program.with_dispatcher(CMDGreet); + program.exec_and_exit(); +} +``` + +Mingling also supports an abbreviated form (with the `extra_macros` feature): + +```rust +// Features: ["extra_macros"] + +// Auto-generates CMDGreet / EntryGreet from "greet" +dispatcher!("greet"); +``` + +--- + +## 2. The Chain — "#[chain]" — Where Logic Lives + +The `#[chain]` attribute turns a plain function into an execution step. Think of it as "the logic that transforms one typed value into another." + +```rust +dispatcher!("greet", CMDGreet => EntryGreet); + +pack!(ResultGreeting = String); + +#[chain] +fn handle_greet(args: EntryGreet) -> Next { + let greeting = args + .inner + .first() + .cloned() + .unwrap_or_else(|| "World".to_string()); + ResultGreeting::new(greeting).into() +} +``` + +Key points: + +- The return type is `Next` — a type alias for `ChainProcess<ThisProgram>`. +- You chain results by calling `.to_chain()` on any `pack!`-ed type. +- You can have **multiple chain functions** for the same command, each transforming the data further. +- With the `async` feature, chain functions can be `async fn`. + +--- + +## 3. The Renderer — "#[renderer]" — How Output Works + +The `#[renderer]` attribute turns a function into an output handler. It receives the final result of a chain and returns a `RenderResult`. + +```rust +use mingling::macros::pack; +use mingling::prelude::*; +use std::io::Write; + +pack!(ResultGreeting = String); + +#[renderer] +fn render_greeting(greeting: ResultGreeting) -> RenderResult { + let mut result = RenderResult::new(); + writeln!(result, "Hello, {}!", *greeting).ok(); + result +} +``` + +Inside a renderer, create a `RenderResult`, write to it using `write!` / `writeln!` (from [`std::io::Write`](https://doc.rust-lang.org/std/io/trait.Write.html)), and return it. The output is captured in the buffer and flushed by the framework at the end of the pipeline. + +You can write renderers for **any type** in your program, including error types: + +```rust +use mingling::prelude::*; +use std::io::Write; + +#[renderer] +fn render_dispatcher_not_found(err: ErrorDispatcherNotFound) -> RenderResult { + let mut result = RenderResult::new(); + writeln!(result, "Command not found: [{}]", err.join(" ")).ok(); + result +} +``` + +--- + +## 4. Parsing Arguments — The Picker + +Mingling provides a **Picker** for zero-cost argument extraction. You use `pick()` or `pick_or()` on an entry to extract typed values, then `unpack()` to get the final tuple. + +```rust +// Features: ["parser"] + +use mingling::parser::Picker; + +dispatcher!("greet", CMDGreet => EntryGreet); +pack!(ResultGreeting = String); + +#[chain] +fn handle_greet(args: EntryGreet) -> Next { + let (name, count) = Picker::new(args.inner) + .pick::<String>(()) // positional: first string + .pick_or::<u8>(["-r", "--repeat"], 1) // optional flag with default + .unpack(); + ResultGreeting::new(format!("{} x{}", name, count)).into() +} +``` + +With the `parser` feature, the `AsPicker` trait provides a shorthand directly on entries: + +```rust +// Features: ["parser"] + +dispatcher!("greet", CMDGreet => EntryGreet); +pack!(ResultGreeting = String); + +#[chain] +fn handle(args: EntryGreet) -> Next { + let (name, count) = args + .pick::<Option<String>>(()) + .pick_or::<u8>(["-r", "--repeat"], 1) + .unpack(); + ResultGreeting::new(format!("{} x{}", name.unwrap_or_default(), count)).into() +} +``` + +For enums, derive `EnumTag` and implement `PickableEnum` to parse enum variants from strings: + +```rust +// Features: ["parser", "extra_macros"] + +use mingling::{EnumTag, Grouped}; +use mingling::parser::PickableEnum; + +dispatcher!("lang.select", CMDLang => EntryLang); + +#[derive(Debug, Default, EnumTag, Grouped)] +pub enum Language { + #[default] + Rust, + #[enum_rename("C++")] + CPlusPlus, +} + +impl PickableEnum for Language {} + +#[chain] +fn handle(args: EntryLang) -> Next { + let lang: Language = args.pick(()).unpack(); + lang.into() +} +``` + +--- + +## 5. The Help System — "#[help]" + +Help is just another attribute macro. When the user passes `--help` or `-h`, the program skips the normal chain/render pipeline and routes directly to your `#[help]` function. + +Enable it by adding `BasicProgramSetup`: + +```rust +use mingling::{macros::help, prelude::*, setup::BasicProgramSetup}; +use std::io::Write; + +dispatcher!("greet", CMDGreet => EntryGreet); + +#[help] +fn help_greet(_prev: EntryGreet) -> RenderResult { + let mut result = RenderResult::new(); + writeln!(result, "Usage: greet <NAME>").ok(); + writeln!(result, "Greets the user with the given name.").ok(); + result +} + +fn main() { + let mut program = ThisProgram::new(); + program.with_setup(BasicProgramSetup); // enables --help / -h + program.with_dispatcher(CMDGreet); + program.exec_and_exit(); +} + +gen_program!(); +``` + +The flow is: + +- User types `greet --help` +- `BasicProgramSetup` sets `program.user_context.help = true` +- The dispatcher sees this flag and routes to the `#[help]` function instead of the `#[chain]` + +--- + +## 6. Completion — "#[completion]" — Dynamic Shell Completions + +With the `comp` feature, Mingling provides a fully dynamic completion system. You write a function that returns `Suggest` based on the current shell context, and Mingling generates the completion scripts for bash, zsh, fish, and pwsh. + +```rust +// Features: ["comp", "extra_macros"] + +use mingling::{macros::suggest, ShellContext, Suggest}; + +dispatcher!("greet", CMDGreet => EntryGreet); +pack!(ResultName = (u8, String)); + +#[completion(EntryGreet)] +fn complete_greet(ctx: &ShellContext) -> Suggest { + // Suggest positional arguments + if ctx.previous_word == "greet" { + return suggest! { + "Alice": "Likes to receive messages", + "Bob": "Likes to pass messages", + "World" + }; + } + + // Suggest flag arguments + if ctx.typing_argument() { + return suggest! { + "-r": "Number of repetitions", + "--repeat": "Number of repetitions", + } + .strip_typed_argument(ctx); + } + + suggest!() // no suggestions +} +``` + +You also need to register the built-in completion dispatcher: + +```rust +// Features: ["comp"] + +fn main() { + let mut program = ThisProgram::new(); + program.with_dispatcher(crate::CMDCompletion); + program.exec_and_exit(); +} +``` + +In your `build.rs`, generate the shell scripts: + +```rust +// BUILD TIME +// Features: ["comp", "builds"] +mingling::build::build_comp_scripts(env!("CARGO_PKG_NAME")).unwrap(); +``` + +For enum-based completions, use `suggest_enum!`: + +```rust +// Features: ["comp", "extra_macros"] + +use mingling::{ShellContext, Suggest}; +use mingling::macros::suggest_enum; +use mingling::EnumTag; + +dispatcher!("lang.select", CMDLang => EntryLang); + +#[derive(EnumTag)] +pub enum ProgrammingLanguages { + Rust, + Python, + JavaScript, +} + +#[completion(EntryLang)] +fn complete_lang(_: &ShellContext) -> Suggest { + suggest_enum!(ProgrammingLanguages) +} +``` + +--- + +## 7. Error Handling + +Mingling doesn't use `?` operator propagation. Instead, errors are just **alternative results** that flow through the same chain/render pipeline. Create error types with `pack!` and route to them with `.to_render()`: + +```rust +use mingling::macros::pack; +use mingling::prelude::*; +use std::io::Write; + +dispatcher!("hello", CMDHello => EntryHello); +pack!(ResultName = String); +pack!(ErrorNoNameProvided = ()); +pack!(ErrorNameTooLong = u16); + +#[chain] +fn handle(args: EntryHello) -> Next { + let Some(name) = args.inner.first().cloned() else { + return ErrorNoNameProvided::default().to_render(); // ← early return to error renderer + }; + + if name.len() > 10 { + return ErrorNameTooLong::new(name.len() as u16).to_render(); + } + + ResultName::new(name).to_render() // ← success path +} + +#[renderer] +fn render_no_name(_: ErrorNoNameProvided) -> RenderResult { + let mut result = RenderResult::new(); + writeln!(result, "No name provided").ok(); + result +} + +#[renderer] +fn render_too_long(len: ErrorNameTooLong) -> RenderResult { + let mut result = RenderResult::new(); + writeln!(result, "Name too long: {} > 10", *len).ok(); + result +} +``` + +Two built-in fallback types are always available: + +- `ErrorDispatcherNotFound` — rendered when no dispatcher matches the input +- `ErrorRendererNotFound` — rendered when no renderer is found for a result type + +--- + +## 8. Resource Injection + +Chain and renderer functions can accept **additional parameters** for the program's global state. Resources are singleton values registered with `program.with_resource(...)`. + +```rust +// Features: ["parser", "extra_macros"] + +use std::path::PathBuf; + +dispatcher!("current", CMDCurrent => EntryCurrent); +dispatcher!("cd", CMDCd => EntryCd); + +#[derive(Default, Clone)] +struct ResCurrentDir { + current_dir: PathBuf, +} + +fn main() { + let mut program = ThisProgram::new(); + program.with_resource(ResCurrentDir { + current_dir: std::env::current_dir().unwrap(), + }); + program.with_dispatcher(CMDCurrent); + program.with_dispatcher(CMDCd); + program.exec_and_exit(); +} + +// Read-only access (shared reference): +#[chain] +fn show_current(_prev: EntryCurrent, current_dir: &ResCurrentDir) -> Next { + println!("Current: {}", current_dir.current_dir.display()); + empty_result!() +} + +// Mutable access: +#[chain] +fn change_dir(prev: EntryCd, current_dir: &mut ResCurrentDir) -> Next { + let path: String = prev.pick(()).unpack(); + current_dir.current_dir = current_dir.current_dir.join(path); + empty_result!() +} +``` + +Resources can also be injected into `#[renderer]`: + +```rust +use mingling::prelude::*; +use std::io::Write; + +dispatcher!("current", CMDCurrent => EntryCurrent); + +#[derive(Default, Clone)] +struct ResCurrentDir { + current_dir: std::path::PathBuf, +} + +#[renderer] +fn render_current(_: EntryCurrent, current_dir: &ResCurrentDir) -> RenderResult { + let mut result = RenderResult::new(); + writeln!(result, "Current directory: {}", current_dir.current_dir.display()).ok(); + result +} +``` + +--- + +## 9. Dispatch Tree — Compile-Time Command Trie + +As your program grows to dozens or hundreds of subcommands, linear dispatcher lookup becomes slow. Enable the `dispatch_tree` feature to convert the command structure into a **prefix tree (Trie)** at compile time. + +```rust +// Features: ["dispatch_tree"] + +dispatcher!("cmd1", CMD1 => Entry1); +dispatcher!("cmd2.sub1", CMD2Sub1 => Entry2Sub1); +dispatcher!("cmd2.sub2", CMD2Sub2 => Entry2Sub2); +dispatcher!("cmd3.sub1.leaf1", CMD3Sub1Leaf1 => Entry3Sub1Leaf1); +dispatcher!("cmd3.sub1.leaf2", CMD3Sub1Leaf2 => Entry3Sub1Leaf2); +// ... dozens more + +fn main() { + let program = ThisProgram::new(); + // No more with_dispatcher calls — it's all compile-time! + program.exec_and_exit(); +} +``` + +With `dispatch_tree` enabled: + +- Dispatchers are auto-collected at compile time +- `Program` no longer stores a dispatcher list +- `program.with_dispatcher(...)` is not compiled +- Lookup is **O(n)** where _n_ is input length, not number of commands + +--- + +## 10. Clap Binding — Using Clap's Parser + +If you prefer clap's powerful argument parsing, use `#[dispatcher_clap]`. It generates a dispatcher from a `clap::Parser` struct. + +```rust +// Features: ["clap"] +// Dependencies: +// clap = "4" + +use mingling::macros::dispatcher_clap; +use mingling::prelude::*; +use std::io::Write; + +#[derive(Default, clap::Parser, Grouped)] +#[dispatcher_clap( + "greet", CMDGreet, + help = true, // auto-generate #[help] from clap + error = ErrorGreetParsed, // capture parse errors as a renderable type +)] +pub struct EntryGreet { + #[clap(default_value = "World")] + name: String, + + #[arg(short, long, default_value_t = 1)] + repeat: i32, +} + +#[renderer] +fn render_greet(greet: EntryGreet) -> RenderResult { + let mut result = RenderResult::new(); + write!(result, "Hello, ").ok(); + for _ in 0..greet.repeat { write!(result, "{}", greet.name).ok(); } + writeln!(result, "!").ok(); + result +} + +#[renderer] +fn render_parse_error(err: ErrorGreetParsed) -> RenderResult { + let mut result = RenderResult::new(); + writeln!(result, "{}", *err).ok(); + result +} +``` + +You can control how clap help is displayed: + +```rust +// Features: ["clap"] + +dispatcher!("greet", CMDGreet => EntryGreet); + +fn main() { + let mut program = ThisProgram::new(); + program.with_dispatcher(CMDGreet); + program.stdout_setting.clap_help_print_behaviour = + mingling::ClapHelpPrintBehaviour::WriteToRenderResult; + // or: PrintDirectly — writes clap help straight to stdout + program.exec_and_exit(); +} +``` + +--- + +## 11. REPL Mode + +With the `repl` feature, turn your CLI into an interactive shell with one method call: + +```rust +// Features: ["repl"] + +fn main() { + ThisProgram::new().exec_repl(); +} +``` + +Mingling provides built-in REPL setups: + +```rust +// Features: ["repl", "extra_macros"] + +use mingling::{ + res::ResREPL, + setup::{BasicREPLReadlineSetup, BasicREPLOutputSetup, BasicREPLPromptSetup}, +}; + +dispatcher!("cd", CMDCd => EntryCd); +dispatcher!("exit", CMDExit => EntryExit); + +fn main() { + let mut program = ThisProgram::new(); + + program.with_dispatcher(CMDCd); + program.with_dispatcher(CMDExit); + + // Enable line reading from stdin + program.with_setup(BasicREPLReadlineSetup); + + // Enable output flushing after each render + program.with_setup(BasicREPLOutputSetup); + + // Custom prompt + program.with_setup(BasicREPLPromptSetup::func(|| "> ".to_string())); + + program.exec_repl(); // ← interactive loop +} + +// Exit the REPL via the ResREPL resource: +#[chain] +fn handle_exit(_prev: EntryExit, repl: &mut ResREPL) { + repl.exit = true; +} +``` + +--- + +## 12. Hooks — Observing the Pipeline + +Mingling provides a `ProgramHook` system for observing every stage of the execution pipeline. Useful for debugging, logging, or telemetry. + +```rust +use mingling::{ + hook::{ProgramControlUnit, ProgramHook}, +}; + +dispatcher!("greet", CMDGreet => EntryGreet); + +fn main() { + let mut program = ThisProgram::new(); + + program.with_hook( + ProgramHook::<ThisProgram>::empty() + .on_begin::<_, ()>(|_| println!("[DEBUG] Program is begin")) + .on_pre_dispatch(|info| println!("[DEBUG] Pre dispatch: {}", info.arguments.join(" "))) + .on_post_dispatch(|info| println!("[DEBUG] Post dispatch: {}", info.entry)) + .on_pre_chain(|info| { + println!("[DEBUG] Pre chain: {}", info.input); + }) + .on_post_chain(|info| println!("[DEBUG] Post chain: {}", info.output.member_id)) + .on_finish(|_| { + println!("[DEBUG] Loop end"); + ProgramControlUnit::OverrideExitCode(0) // Override exit code + }) + .on_pre_render(|info| println!("[DEBUG] Pre render: {}", info.input)) + .on_post_render(|_| println!("[DEBUG] Post render")), + ); + + program.with_dispatcher(CMDGreet); + program.exec_and_exit(); +} +``` + +--- + +## 13. Structural Renderer — Structured Output (JSON/YAML) + +With the `structural_renderer` feature, users can add `--json` or `--yaml` flags to get structured output instead of human-readable text. + +```rust +// Features: ["structural_renderer", "parser"] +// Dependencies: +// serde = "1" + +use mingling::{prelude::*, setup::StructuralRendererSetup}; +use mingling::Grouped; +use mingling::StructuralData; +use serde::Serialize; +use std::io::Write; + +dispatcher!("render", CMDRender => EntryRender); + +#[derive(Default, StructuralData, Serialize, Grouped)] +struct ResultInfo { + name: String, + age: i32, +} + +#[chain] +fn render_info(args: EntryRender) -> Next { + let (name, age) = args.pick::<String>(()).pick::<i32>(()).unpack(); + ResultInfo { name, age }.to_chain() +} + +#[renderer] +fn render_info_result(info: ResultInfo) -> RenderResult { + let mut result = RenderResult::new(); + writeln!(result, "{} is {} years old", info.name, info.age).ok(); + result +} + +fn main() { + let mut program = ThisProgram::new(); + program.with_setup(StructuralRendererSetup); // enables --json / --yaml + program.with_dispatcher(CMDRender); + let _ = program.exec(); +} +``` + +Then users can do: + +```bash +$ myapp render Bob 22 +Bob is 22 years old + +$ myapp render Bob 22 --json +{"name":"Bob","age":22} + +$ myapp render Bob 22 --yaml +name: Bob +age: 22 +``` + +--- + +## 14. Async Support + +Enable the `async` feature to use `async fn` inside `#[chain]`: + +```rust +// Features: ["async", "parser"] +// Dependencies: +// tokio = { version = "1", features = ["full"] } + +use std::io::Write; +use std::time::Duration; + +dispatcher!("download", CMDDownload => EntryDownload); +pack!(ResultDownloaded = String); + +#[chain] +pub async fn handle_download(args: EntryDownload) -> Next { + let file = args.pick(()).unpack(); + download_file(file).await.into() +} + +async fn download_file(name: String) -> ResultDownloaded { + tokio::time::sleep(Duration::from_secs(1)).await; + ResultDownloaded::new(name) +} + +#[renderer] +fn render_downloaded(result: ResultDownloaded) -> RenderResult { + let mut r = RenderResult::new(); + writeln!(r, "\"{}\" downloaded.", *result).ok(); + r +} +``` + +> [!NOTE] +> +> `#[renderer]` functions cannot be async. When `async` is enabled, `program.exec_and_exit().await` returns a Future. + +--- + +## 15. Wrapping Up — `gen_program!()` + +At the very end of your crate root (main.rs / lib.rs), call `gen_program!()` to generate the `ThisProgram` struct, the `Next` type alias, and all internal plumbing. + +```rust +use mingling::macros::gen_program; + +gen_program!(); +``` + +It must be placed **after** all your `dispatcher!`, `pack!`, `#[chain]`, `#[renderer]`, and `#[help]` declarations. + +--- + +## Putting It All Together + +Here's a complete, runnable program: + +```rust +use mingling::macros::pack; +use mingling::prelude::*; +use std::io::Write; + +dispatcher!("greet", CMDGreet => EntryGreet); + +fn main() { + let mut program = ThisProgram::new(); + program.with_dispatcher(CMDGreet); + program.exec_and_exit(); +} + +pack!(ResultGreeting = String); + +#[chain] +fn handle_greet(args: EntryGreet) -> Next { + let greeting = args + .inner + .first() + .cloned() + .unwrap_or_else(|| "World".to_string()); + ResultGreeting::new(greeting).into() +} + +#[renderer] +fn render_greeting(greeting: ResultGreeting) -> RenderResult { + let mut result = RenderResult::new(); + writeln!(result, "Hello, {}!", *greeting).ok(); + result +} + +gen_program!(); +``` + +```bash +$ myapp greet +Hello, World! + +$ myapp greet Alice +Hello, Alice! +``` |