Runtime concepts for the C++ standard template library

A key benefit of generic programming is its support for producing modules with clean separation. In particular, generic algorithms are written to work with a wide variety of unmodified types. The Runtime concept idiom extends this support by allowing unmodified concrete types to behave in a runtime polymorphic manner. In this paper, we describe one implementation of the runtime concept idiom, in the domain of the C++ standard template library (STL). We describe and measure the performance of runtime-polymorphic analogs of several STL algorithms. We augment the runtime concept idiom by employing a dispatch mechanism that considers both type and concept information to maximize performance when selecting algorithm implementations. We use our implementation to demonstrate the effects of different compile-time vs. run-time algorithm selection choices, and we indicate where improved language and compiler support would be useful. Categories and Subject Descriptors

• Type: Journal
• Year: 2008
• Where: SAC
• Authors: Peter Pirkelbauer, Sean Parent, Mat Marcus, Bjarne Stroustrup
• Keywords: Algorithm, Applied Computing, Runtime Concept Idiom, Runtime Polymorphic Manner, SAC 2008