feat: .NET Support (#73)

Adds support for generating a .NET (C#) project.

I choose `namespace` rather than `package` since it seemed more appropriate when generating source code.

I went with `dotnet` since it matches the jsii naming, but `csharp` may make more sense for configuration options / cli parameters. I don't believe there are any plans to generate F# code in jsii, but if there were, I'd lean towards using `csharp` naming.

Author: jsteinich

README.md

@@ -97,6 +97,35 @@ original module. This code depends on the following maven package (should be def
 
 The output directory will also include a tarball `generated@0.0.0.jsii.tgz` that must be bundled in your project.
 
+### C# Output
+
+To produce a C# module from your source, use the `csharp` option:
+
+```ts
+await srcmak('srcdir', {
+  csharp: {
+    outdir: '/path/to/project/root',
+    namespace: 'HelloWorld'
+  }
+});
+```
+
+Or the `--csharp-*` switches in the CLI:
+
+```bash
+$ jsii-srcmak /src/dir --csharp-outdir=dir --csharp-namespace=HelloWorld
+```
+
+* The `outdir`/`--csharp-outdir` option points to the root directory of your C# project.
+* The `package`/`--csharp-namespace` option is the C# root namespace.
+
+The output directory will include a C# project that corresponds to the
+original module. This code depends on the following NuGet package (It is already defined as a dependency in the generated project):
+
+- [jsii](https://www.nuget.org/packages/Amazon.JSII.Runtime/)
+
+The output directory will also include a tarball `generated@0.0.0.jsii.tgz` that must be bundled in your project (It is already included as an embedded resource in the generated project).
+
 ### Entrypoint
 
 The `entrypoint` option can be used to customize the name of the typescript entrypoint (default is `index.ts`).

src/cli.ts

@@ -11,6 +11,8 @@ async function main() {
     .option('python-module-name', { desc: 'python module name', type: 'string' })
     .option('java-outdir', { desc: 'java output directory (requires --java-package)', type: 'string' })
     .option('java-package', { desc: 'the java package (namespace) to use for all generated types', type: 'string' })
+    .option('csharp-outdir', { desc: 'C# output directory (requires --csharp-namespace)', type: 'string' })
+    .option('csharp-namespace', { desc: 'the C# namespace to use for all generated types', type: 'string' })
     .showHelpOnFail(true)
     .help();
 
@@ -30,6 +32,7 @@ async function main() {
     ...parseJsiiOptions(),
     ...parsePythonOptions(),
     ...parseJavaOptions(),
+    ...parseCSharpOptions(),
   });
 
   function parseJsiiOptions() {
@@ -70,6 +73,20 @@ async function main() {
     }
   }
 
+  function parseCSharpOptions() {
+    const outdir = argv['csharp-outdir'];
+    const namespace = argv['csharp-namespace'];
+    if (!outdir && !namespace) { return undefined; }
+    if (!outdir) { throw new Error('--csharp-outdir is required'); }
+    if (!namespace) { throw new Error('--csharp-namespace is required'); }
+    return {
+      csharp: {
+        outdir: outdir,
+        namespace: namespace,
+      },
+    }
+  }
+
   function parseDepOption() {
     if (argv.dep?.length === 0) { return undefined; }
     return {

src/compile.ts

@@ -84,6 +84,13 @@ export async function compile(workdir: string, options: Options) {
     };
   }
 
+  if (options.csharp) {
+    targets.dotnet = {
+      namespace: options.csharp.namespace,
+      packageId: options.csharp.namespace,
+    };
+  }
+
   await fs.writeFile(path.join(workdir, 'package.json'), JSON.stringify(pkg, undefined, 2));
 
   await exec(compilerModule, args, {

src/options.ts

@@ -39,6 +39,13 @@ export interface Options {
    * @default - java is not generated
    */
   java?: JavaOutputOptions;
+
+  /**
+   * Produces C# code.
+   * 
+   * @default - C# is not generated
+   */
+  csharp?: CSharpOutputOptions;
 }
 
 export interface JsiiOutputOptions {
@@ -77,3 +84,18 @@ export interface JavaOutputOptions {
    */
   package: string;
 }
+
+export interface CSharpOutputOptions {
+  /**
+   * Base root directory.
+   */
+  outdir: string;
+
+  /**
+   * The root namespace to generate types in
+   * 
+   * This must follow standard C# namespace conventions.
+   * For example, it cannot include a hyphen ('-')
+   */
+  namespace: string;
+}

src/srcmak.ts

@@ -44,5 +44,12 @@ export async function srcmak(srcdir: string, options: Options = { }) {
       await fs.mkdirp(target); // make sure target directory exists
       await ncp(source, target, { clobber: false });
     }
+
+    if (options.csharp) {
+      const reldir = options.csharp.namespace;
+      const source = path.resolve(path.join(workdir, 'dist/dotnet/', reldir));
+      const target = path.join(options.csharp.outdir, reldir);
+      await fs.move(source, target, { overwrite: true });
+    }
   });
 }

src/util.ts

@@ -58,7 +58,7 @@ export async function exec(moduleName: string, args: string[] = [], options: Spa
 }
 
 /**
- * This validates that the Python module name and Java package name
+ * This validates that the Python module name, Java package name, and C# namespace
  * conform to language-specific constraints.
  * 
  * @param options Options set by the consumer
@@ -72,4 +72,8 @@ export function validateOptions(options: Options) {
   if (options.java?.package.includes('-')) {
     throw new Error(`Java package [${options.java.package}] may not contain "-"`);
   }
+
+  if (options.csharp?.namespace.includes('-')) {
+    throw new Error(`C# namespace [${options.csharp.namespace}] may not contain "-"`);
+  }
 }