public emit()

in packages/jsii-pacmak/lib/targets/python.ts [1576:1698]

• 93 lines of code
• 11 McCabe index (conditional complexity)

  public emit(code: CodeMaker, context: EmitContext) {
    this.emitModuleDocumentation(code);

    const resolver = this.fqn
      ? context.resolver.bind(this.fqn, this.pythonName)
      : context.resolver;
    context = {
      ...context,
      submodule: this.fqn ?? context.submodule,
      resolver,
    };

    // Before we write anything else, we need to write out our module headers, this
    // is where we handle stuff like imports, any required initialization, etc.
    code.line('import abc');
    code.line('import builtins');
    code.line('import datetime');
    code.line('import enum');
    code.line('import typing');
    code.line();
    code.line('import jsii');
    code.line('import publication');
    code.line('import typing_extensions');

    // Determine if we need to write out the kernel load line.
    if (this.loadAssembly) {
      this.emitDependencyImports(code);

      code.line();
      emitList(
        code,
        '__jsii_assembly__ = jsii.JSIIAssembly.load(',
        [
          JSON.stringify(this.assembly.name),
          JSON.stringify(this.assembly.version),
          '__name__[0:-6]',
          `${JSON.stringify(this.assemblyFilename)}`,
        ],
        ')',
      );
    } else {
      // Then we must import the ._jsii subpackage.
      code.line();
      let distanceFromRoot = 0;
      for (
        let curr = this.fqn!;
        curr !== this.assembly.name;
        curr = curr.substring(0, curr.lastIndexOf('.'))
      ) {
        distanceFromRoot++;
      }
      code.line(`from ${'.'.repeat(distanceFromRoot + 1)}_jsii import *`);

      this.emitRequiredImports(code, context);
    }

    // Emit all of our members.
    for (const member of prepareMembers(this.members, resolver)) {
      code.line();
      code.line();
      member.emit(code, context);
    }

    // Whatever names we've exported, we'll write out our __all__ that lists them.
    const exportedMembers = this.members.map((m) => `"${m.pythonName}"`);
    if (this.loadAssembly) {
      exportedMembers.push('"__jsii_assembly__"');
    }

    // Declare the list of "public" members this module exports
    if (this.members.length > 0) {
      code.line();
    }
    code.line();

    if (exportedMembers.length > 0) {
      code.indent('__all__ = [');
      for (const member of exportedMembers.sort()) {
        // Writing one by line might be _a lot_ of lines, but it'll make reviewing changes to the list easier. Trust me.
        code.line(`${member},`);
      }
      code.unindent(']');
    } else {
      code.line('__all__: typing.List[typing.Any] = []');
    }

    // Next up, we'll use publication to ensure that all of the non-public names
    // get hidden from dir(), tab-complete, etc.
    code.line();
    code.line('publication.publish()');

    // Finally, we'll load all registered python modules
    if (this.modules.length > 0) {
      code.line();
      code.line(
        '# Loading modules to ensure their types are registered with the jsii runtime library',
      );
      for (const module of this.modules.sort((l, r) =>
        l.pythonName.localeCompare(r.pythonName),
      )) {
        // Rather than generating an absolute import like
        // "import jsii_calc.submodule.nested_submodule.deeply_nested"
        // this builds a relative import like
        // "from .submodule.nested_submodule import deeply_nested"
        // This enables distributing python packages and using the
        // generated modules in the same codebase.
        const assemblyName = toPythonFqn(
          module.assembly.name,
          module.assembly,
        ).pythonFqn;

        const submodule = module.pythonName
          .replace(`${assemblyName}.`, '')
          .split('.');

        const submodulePath = submodule
          .slice(0, submodule.length - 1)
          .join('.');
        const submoduleName = submodule[submodule.length - 1];
        code.line(`from .${submodulePath} import ${submoduleName}`);
      }
    }
  }