Merge pull request #93 from moonbitlang/update-moon-tutorial-2

update build system tutorial

moon_build_system_tutorial.md

@@ -15,18 +15,19 @@ Before you begin with this tutorial, make sure you have installed the following:
     Usage: moon <COMMAND>
 
     Commands:
-    build    Build the current package
-    check    Check the current package, but don't build object files
-    run      Run WebAssembly module
-    clean    Remove the target directory
-    new      Create a new moonbit package
-    bench    Generate build matrix for benchmarking
-    fmt      Format moonbit
-    version  Print version info and exit
-    help     Print this message or the help of the given subcommand(s)
+      build    Build the current package
+      check    Check the current package, but don't build object files
+      run      Run WebAssembly module
+      clean    Remove the target directory
+      new      Create a new moonbit package
+      bench    Generate build matrix for benchmarking
+      fmt      Format moonbit
+      version  Print version info and exit
+      test     Run the tests
+      help     Print this message or the help of the given subcommand(s)
 
     Options:
-    -h, --help  Print help
+      -h, --help  Print help
     ```
 
 2. **Moonbit Language** plugin in Visual Studio Code: You can install it from the VS Code marketplace. This plugin provides a rich development environment for MoonBit, including functionalities like syntax highlighting, code completion, and more.
@@ -51,23 +52,25 @@ After creating the new module, your directory structure should resemble the foll
 .
 ├── lib
 │   ├── hello.mbt
-│   └── moon.pkg
+│   └── moon.pkg.json
 ├── main
 │   ├── main.mbt
-│   └── moon.pkg
-└── moon.mod
+│   └── moon.pkg.json
+└── moon.mod.json
 ```
 
 Here's a brief explanation of the directory structure:
 
-- `lib` and `main` directories: These are packages in the module. Each package can contain multiple `.mbt` files, which are the source code files in MoonBit language. However, regardless of the number of `.mbt` files in a package, they all share a common `moon.pkg` file.
+- `lib` and `main` directories: These are packages in the module. Each package can contain multiple `.mbt` files, which are the source code files in MoonBit language. However, regardless of the number of `.mbt` files in a package, they all share a common `moon.pkg.json` file.
 
-- `moon.pkg` is package descriptor. It defines the properties of the package, such as its name, and the packages it imports.
+- `moon.pkg.json` is package descriptor. It defines the properties of the package, such as its name, and the packages it imports.
 
-- `moon.mod` is used to identify a directory as a MoonBit module. It contains the module's name:
+- `moon.mod.json` is used to identify a directory as a MoonBit module. It contains the module's name:
 
-  ```go
-  module "hello"
+  ```json
+  {
+    "name": "hello"
+  }
   ```
 
 ## Checking Your Project
@@ -87,16 +90,16 @@ Our `hello` module contains two packages: `lib` and `main`.
 The `lib` package contains a `hello.mbt` file:
 
 ```rust
-pub func hello() -> String {
+pub fn hello() -> String {
     "Hello, world!\n"
 }
 ```
 
 The `main` package contains a `main.mbt` file:
 
 ```rust
-func init {
-  print(@lib.hello())
+fn init {
+  println(@lib.hello())
 }
 ```
 
@@ -110,15 +113,18 @@ Hello, world!
 ## Package Importing
 
 In the MoonBit's build system, a module's name is used to reference its internal packages.
-To import the `lib` package in `main/main.mbt`, you need to specify it in `main/moon.pkg`:
-
-```go
-package main
+To import the `lib` package in `main/main.mbt`, you need to specify it in `main/moon.pkg.json`:
 
-import "hello/lib"
+```json
+{
+  "name": "main",
+  "import": {
+    "hello/lib": ""
+  }
+}
 ```
 
-Here, `import "hello/lib"` specifies that the `lib` package from the `hello` module is to be imported.
+Here, `"hello/lib": ""` specifies that the `lib` package from the `hello` module is to be imported, and `""` means that `lib` has no name alias.
 
 ## Creating and Using a New Package
 
@@ -133,7 +139,7 @@ Now, you can create new files under `lib/fib`:
 `a.mbt`:
 
 ```rust
-pub func fib(n : Int) -> Int {
+pub fn fib(n : Int) -> Int {
   match n {
     0 => 0
     1 => 1
@@ -145,7 +151,7 @@ pub func fib(n : Int) -> Int {
 `b.mbt`:
 
 ```rust
-pub func fib2(num : Int) -> Int {
+pub fn fib2(num : Int) -> Int {
   fn aux(n, acc1, acc2) {
     match n {
       0 => acc1
@@ -158,10 +164,12 @@ pub func fib2(num : Int) -> Int {
 }
 ```
 
-`moon.pkg`:
+`moon.pkg.json`:
 
-```
-package fib
+```json
+{
+  "name": "fib"
+}
 ```
 
 After creating these files, your directory structure should look like this:
@@ -172,28 +180,34 @@ After creating these files, your directory structure should look like this:
 │   ├── fib
 │   │   ├── a.mbt
 │   │   ├── b.mbt
-│   │   └── moon.pkg
+│   │   └── moon.pkg.json
 │   ├── hello.mbt
-│   └── moon.pkg
+│   └── moon.pkg.json
 ├── main
 │   ├── main.mbt
-│   └── moon.pkg
-└── moon.mod
+│   └── moon.pkg.json
+└── moon.mod.json
 ```
 
-In the `main/moon.pkg` file, add the following line:
+In the `main/moon.pkg.json` file, import package `hello/lib/fib`:
 
-```go
-import "hello/lib/fib"
+```json
+{
+  "name": "main",
+  "import": {
+    "hello/lib": "",
+    "hello/lib/fib": ""
+  }
+}
 ```
 
-This line imports the `fib` package, which is part of the `lib` package in the `hello` module. After doing this, you can use the `lib/fib` package in `main/main.mbt`. Replace the file content of `main/main.mbt` to:
+This line imports the `fib` package, which is part of the `lib` package in the `hello` module. After doing this, you can use the `fib` package in `main/main.mbt`. Replace the file content of `main/main.mbt` to:
 
 ```rust
-func init {
+fn init {
   let a = @fib.fib(10)
   let b = @fib.fib2(11)
-  print("fib(10) = \(a), fib(11) = \(b)\n")
+  println("fib(10) = \(a), fib(11) = \(b)")
 }
 ```
 
@@ -203,3 +217,34 @@ To execute your program, specify the path to the `main` package:
 $ moon run ./main
 fib(10) = 55, fib(11) = 89
 ```
+
+## Adding tests
+
+In the last, let's add some tests to verify our fib implementation.
+
+First, inside the `lib/fib` directory, create a file named `fib_test.mbt` and paste the following code:
+
+```rust
+fn assert_eq[T: Eq](lhs: T, rhs: T) {
+  if lhs != rhs {
+    abort("")
+  }
+}
+
+fn init {
+  assert_eq(fib(1), 1)
+  assert_eq(fib(2), 1)
+  assert_eq(fib(3), 2)
+  assert_eq(fib(4), 3)
+  assert_eq(fib(5), 5)
+}
+```
+
+This code tests the first five terms of the Fibonacci sequence.
+
+Finally, use the command `moon test` which scans the module, identifying and running all files ending with `_test.mbt`. If everything works, you'll see:
+
+```bash
+$ moon test      
+test lib/fib ... ok
+```