A language-based model to support asynchronous operations set forth in a synchronous syntax is provided. The asynchronous operations are transformed in a compiler into an asynchronous pattern, such as an APM-based pattern (or asynchronous programming model based pattern). The ability to compose asynchronous operations comes from the ability to efficiently call asynchronous methods from other asynchronous methods, pause them and later resume them, and effectively implementing a single-linked stack. One example includes support for ordered and unordered compositions of asynchronous operations. In an ordered composition, each asynchronous operation is started and finished before another operation in the composition is started. In an unordered composition, each asynchronous operation is started and completed independently of the operations in the unordered composition.