Introduce the build command in the CLI

README.md

@@ -132,7 +132,7 @@ function writeOutput(output) {
 Create a WebAssembly binary from your JavaScript by:
 
 ```bash
-javy compile index.js -o destination/index.wasm
+javy build index.js -o destination/index.wasm
 ```
 
 For more information on the commands you can run `javy --help`
@@ -147,12 +147,12 @@ $ echo '{ "n": 2, "bar": "baz" }' | wasmtime index.wasm
 If you have a lot of JavaScript and you want to reduce compile times, try using the `--no-source-compression` flag. It will skip compressing the JavaScript source code when generating the Wasm module but will result in the Wasm module being larger.
 
 ```bash
-javy compile index.js -o destination/index.wasm --no-source-compression
+javy build index.js -o destination/index.wasm --no-source-compression
 ```
 
 ### Exporting functions
 
-To export exported JavaScript functions, you can pass a WIT file and WIT world when running `javy compile`. Only ESM exports are supported (that is, Node.js/CommonJS exports are _not_ supported). For each exported JavaScript function, Javy will add an additional function export to the WebAssembly module. Exported functions with arguments and generators are not supported. Return values will also be dropped and not returned. The Wasm module generated is a core Wasm module, **not** a Wasm component.
+To export exported JavaScript functions, you can pass a WIT file and WIT world when running `javy build`. Only ESM exports are supported (that is, Node.js/CommonJS exports are _not_ supported). For each exported JavaScript function, Javy will add an additional function export to the WebAssembly module. Exported functions with arguments and generators are not supported. Return values will also be dropped and not returned. The Wasm module generated is a core Wasm module, **not** a Wasm component.
 
 An example looks like:
 
@@ -176,13 +176,13 @@ world index-world {
 
 In the terminal:
 ```bash
-$ javy compile index.js --wit index.wit -n index-world -o index.wasm
+$ javy build index.js --wit index.wit -n index-world -o index.wasm
 $ wasmtime run --invoke foo index.wasm
 Hello world!
 Hello from foo!
 ```
 
-The WIT package name and WIT world name do not matter as long as they are present and syntactically correct WIT (that is, it needs to be two names separated by a `:`). The name of the WIT world (that is, the value after `world` and before `{`) must be passed as the `-n` argument. The `-n` argument identifies the WIT world in the WIT file for the Wasm module generated by `javy compile`.
+The WIT package name and WIT world name do not matter as long as they are present and syntactically correct WIT (that is, it needs to be two names separated by a `:`). The name of the WIT world (that is, the value after `world` and before `{`) must be passed as the `-n` argument. The `-n` argument identifies the WIT world in the WIT file for the Wasm module generated by `javy build`.
 
 #### Exports with multiple words
 
@@ -206,7 +206,7 @@ world index {
 
 In the terminal:
 ```bash
-$ javy compile index.js --wit index.wit -n index -o index.wasm
+$ javy build index.js --wit index.wit -n index -o index.wasm
 $ wasmtime run --invoke foo-bar index.wasm
 In foo-bar
 ```
@@ -233,7 +233,7 @@ world index {
 
 In the terminal:
 ```bash
-$ javy compile index.js --wit index.wit -n index -o index.wasm
+$ javy build index.js --wit index.wit -n index -o index.wasm
 $ wasmtime run --invoke default index.wasm
 In default
 ```
@@ -271,7 +271,7 @@ The `javy_quickjs_provider.wasm` module is available as an asset on the Javy rel
 
 ```
 $ echo 'console.log("hello world!");' > my_code.js
-$ javy compile -d -o my_code.wasm my_code.js
+$ javy build -d -o my_code.wasm my_code.js
 $ javy emit-provider -o provider.wasm
 $ wasmtime run --preload javy_quickjs_provider_v2=provider.wasm my_code.wasm
 hello world!

crates/cli/src/codegen/builder.rs

@@ -0,0 +1,115 @@
+use crate::codegen::{CodeGen, CodeGenType, DynamicGenerator, StaticGenerator};
+use anyhow::{bail, Result};
+use std::path::PathBuf;
+
+/// Options for using WIT in the code generation process.
+#[derive(Default)]
+pub(crate) struct WitOptions {
+    /// The path of the .wit file to use.
+    pub path: Option<PathBuf>,
+    /// The name of the wit world to use.
+    pub world: Option<String>,
+}
+
+impl WitOptions {
+    pub fn from_tuple(opts: (Option<PathBuf>, Option<String>)) -> Result<Self> {
+        match opts {
+            (None, None) => Ok(Self {
+                path: None,
+                world: None,
+            }),
+            (None, Some(_)) => Ok(Self {
+                path: None,
+                world: None,
+            }),
+            (Some(_), None) => bail!("Must provide WIT world when providing WIT file"),
+            (path, world) => Ok(Self { path, world }),
+        }
+    }
+
+    /// Whether WIT options were defined.
+    pub fn defined(&self) -> bool {
+        self.path.is_some() && self.world.is_some()
+    }
+
+    /// Unwraps a refernce to the .wit file path.
+    pub fn unwrap_path(&self) -> &PathBuf {
+        self.path.as_ref().unwrap()
+    }
+
+    /// Unwraps a reference to the WIT world name.
+    pub fn unwrap_world(&self) -> &String {
+        self.world.as_ref().unwrap()
+    }
+}
+
+/// A code generation builder.
+#[derive(Default)]
+pub(crate) struct CodeGenBuilder {
+    /// The QuickJS provider module version.
+    provider_version: Option<&'static str>,
+    /// WIT options for code generation.
+    wit_opts: WitOptions,
+    /// Whether to compress the original JS source.
+    source_compression: bool,
+}
+
+impl CodeGenBuilder {
+    /// Create a new [`CodeGenBuilder`].
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Set the provider version.
+    pub fn provider_version(&mut self, v: &'static str) -> &mut Self {
+        self.provider_version = Some(v);
+        self
+    }
+
+    /// Set the wit options.
+    pub fn wit_opts(&mut self, opts: WitOptions) -> &mut Self {
+        self.wit_opts = opts;
+        self
+    }
+
+    /// Whether to compress the JS source.
+    pub fn source_compression(&mut self, compress: bool) -> &mut Self {
+        self.source_compression = compress;
+        self
+    }
+
+    /// Build a [`CodeGenerator`].
+    pub fn build<T>(self) -> Result<Box<dyn CodeGen>>
+    where
+        T: CodeGen,
+    {
+        match T::classify() {
+            CodeGenType::Static => self.build_static(),
+            CodeGenType::Dynamic => self.build_dynamic(),
+        }
+    }
+
+    fn build_static(self) -> Result<Box<dyn CodeGen>> {
+        let mut static_gen = Box::new(StaticGenerator::new());
+
+        static_gen.source_compression = self.source_compression;
+        static_gen.wit_opts = self.wit_opts;
+
+        Ok(static_gen)
+    }
+
+    fn build_dynamic(self) -> Result<Box<dyn CodeGen>> {
+        let mut dynamic_gen = Box::new(DynamicGenerator::new());
+
+        if let Some(v) = self.provider_version {
+            dynamic_gen.import_namespace = String::from("javy_quickjs_provider_v");
+            dynamic_gen.import_namespace.push_str(v);
+        } else {
+            bail!("Provider version not specified")
+        }
+
+        dynamic_gen.wit_opts = self.wit_opts;
+
+        Ok(dynamic_gen)
+    }
+}