A generated grouped representation of existing source code can define regions of the existing source code. A set of the regions that can run in parallel can be identified based on the grouped representation. The grouped representation can be converted into a modified representation, such as modified source code or a modified intermediate compiler representation, which can be configured to be resolved or executed to self-schedule the set of regions to run in parallel as a set of tasks. Additionally, the source code can include one or more exception handling routines, and user input can be received to identify in one or more lambda expressions one or more regions of the source code to be run in parallel as one or more tasks.