[xorcist]

Sure, of course I prefer shorter code. But I'd much rather read a hundred straightforward lines than wrap my head around yet another abstraction (of which there are thousands in any non trivial codebase).

I must disagree on the switch statement. A main loop with an rather large switch statement is a perfectly normal way to write a trivial interpreter. C provides a nice way of doing it, and as long as you declare your constants properly it's all perfectly readable. A lot of excellent code bases are structured that way. (Awk comes to mind, IIRC, and it's very easy to read and extend.)