public emit()

in packages/jsii-pacmak/lib/targets/python.ts [572:743]

• 125 lines of code
• 21 McCabe index (conditional complexity)

  public emit(
    code: CodeMaker,
    context: EmitContext,
    opts?: BaseMethodEmitOpts,
  ) {
    const { renderAbstract = true, forceEmitBody = false } = opts ?? {};

    const returnType: string = toTypeName(this.returns).pythonType(context);

    // We cannot (currently?) blindly use the names given to us by the JSII for
    // initializers, because our keyword lifting will allow two names to clash.
    // This can hopefully be removed once we get https://github.com/aws/jsii/issues/288
    // resolved, so build up a list of all of the prop names so we can check against
    // them later.
    const liftedPropNames = new Set<string>();
    if (this.liftedProp?.properties != null) {
      for (const prop of this.liftedProp.properties) {
        liftedPropNames.add(toPythonParameterName(prop.name));
      }
    }

    // We need to turn a list of JSII parameters, into Python style arguments with
    // gradual typing, so we'll have to iterate over the list of parameters, and
    // build the list, converting as we go.
    const pythonParams: string[] = [];
    for (const param of this.parameters) {
      // We cannot (currently?) blindly use the names given to us by the JSII for
      // initializers, because our keyword lifting will allow two names to clash.
      // This can hopefully be removed once we get https://github.com/aws/jsii/issues/288
      // resolved.
      const paramName: string = toPythonParameterName(
        param.name,
        liftedPropNames,
      );

      const paramType = toTypeName(param).pythonType({
        ...context,
        parameterType: true,
      });
      const paramDefault = param.optional ? ' = None' : '';

      pythonParams.push(`${paramName}: ${paramType}${paramDefault}`);
    }

    const documentableArgs: DocumentableArgument[] = this.parameters
      .map(
        (p) =>
          ({
            name: p.name,
            docs: p.docs,
            definingType: this.parent,
          }) as DocumentableArgument,
      )
      // If there's liftedProps, the last argument is the struct and it won't be _actually_ emitted.
      .filter((_, index) =>
        this.liftedProp != null ? index < this.parameters.length - 1 : true,
      )
      .map((param) => ({
        ...param,
        name: toPythonParameterName(param.name, liftedPropNames),
      }));

    // If we have a lifted parameter, then we'll drop the last argument to our params
    // and then we'll lift all of the params of the lifted type as keyword arguments
    // to the function.
    if (this.liftedProp !== undefined) {
      // Remove our last item.
      pythonParams.pop();
      const liftedProperties = this.getLiftedProperties(context.resolver);

      if (liftedProperties.length >= 1) {
        // All of these parameters are keyword only arguments, so we'll mark them
        // as such.
        pythonParams.push('*');

        // Iterate over all of our props, and reflect them into our params.
        for (const prop of liftedProperties) {
          const paramName = toPythonParameterName(prop.prop.name);
          const paramType = toTypeName(prop.prop).pythonType({
            ...context,
            parameterType: true,
            typeAnnotation: true,
          });
          const paramDefault = prop.prop.optional ? ' = None' : '';

          pythonParams.push(`${paramName}: ${paramType}${paramDefault}`);
        }
      }

      // Document them as keyword arguments
      documentableArgs.push(
        ...liftedProperties.map(
          (p) =>
            ({
              name: p.prop.name,
              docs: p.prop.docs,
              definingType: p.definingType,
            }) as DocumentableArgument,
        ),
      );
    } else if (
      this.parameters.length >= 1 &&
      this.parameters[this.parameters.length - 1].variadic
    ) {
      // Another situation we could be in, is that instead of having a plain parameter
      // we have a variadic parameter where we need to expand the last parameter as a
      // *args.
      pythonParams.pop();

      const lastParameter = this.parameters.slice(-1)[0];
      const paramName = toPythonParameterName(lastParameter.name);
      const paramType = toTypeName(lastParameter.type).pythonType(context);

      pythonParams.push(`*${paramName}: ${paramType}`);
    }

    const decorators = new Array<string>();

    if (this.jsName !== undefined) {
      decorators.push(`@jsii.member(jsii_name="${this.jsName}")`);
    }

    if (this.decorator !== undefined) {
      decorators.push(`@${this.decorator}`);
    }

    if (renderAbstract && this.abstract) {
      decorators.push('@abc.abstractmethod');
    }

    if (decorators.length > 0) {
      for (const decorator of decorators) {
        code.line(decorator);
      }
    }

    pythonParams.unshift(
      slugifyAsNeeded(
        this.implicitParameter,
        pythonParams.map((param) => param.split(':')[0].trim()),
      ),
    );

    openSignature(code, 'def', this.pythonName, pythonParams, returnType);
    this.generator.emitDocString(code, this.apiLocation, this.docs, {
      arguments: documentableArgs,
      documentableItem: `method-${this.pythonName}`,
    });
    if (
      (this.shouldEmitBody || forceEmitBody) &&
      (!renderAbstract || !this.abstract)
    ) {
      emitParameterTypeChecks(
        code,
        context,
        pythonParams.slice(1),
        `${this.pythonParent.fqn ?? this.pythonParent.pythonName}#${
          this.pythonName
        }`,
      );
    }
    this.emitBody(
      code,
      context,
      renderAbstract,
      forceEmitBody,
      liftedPropNames,
      pythonParams[0],
      returnType,
    );
    code.closeBlock();
  }