Tradeoffs in Metaprogramming
<|reference_start|>Tradeoffs in Metaprogramming: The design of metaprogramming languages requires appreciation of the tradeoffs that exist between important language characteristics such as safety properties, expressive power, and succinctness. Unfortunately, such tradeoffs are little understood, a situation we try to correct by embarking on a study of metaprogramming language tradeoffs using tools from computability theory. Safety properties of metaprograms are in general undecidable; for example, the property that a metaprogram always halts and produces a type-correct instance is $\Pi^0_2$-complete. Although such safety properties are undecidable, they may sometimes be captured by a restricted language, a notion we adapt from complexity theory. We give some sufficient conditions and negative results on when languages capturing properties can exist: there can be no languages capturing total correctness for metaprograms, and no `functional' safety properties above $\Sigma^0_3$ can be captured. We prove that translating a metaprogram from a general-purpose to a restricted metaprogramming language capturing a property is tantamount to proving that property for the metaprogram. Surprisingly, when one shifts perspective from programming to metaprogramming, the corresponding safety questions do not become substantially harder -- there is no `jump' of Turing degree for typical safety properties.<|reference_end|>
@article{veldhuizen2005tradeoffs,
    title={Tradeoffs in Metaprogramming},
    author={Todd L. Veldhuizen},
    journal={arXiv preprint arXiv:cs/0512065},
    year={2005},
    archivePrefix={arXiv},
    eprint={cs/0512065},
    primaryClass={cs.PL}
}