> it depends on what you're implementing them in, but in a term-rewriting language all you need is the two lines above Okay, so what do I type those two lines

> it depends on what you're implementing them in, but in a term-rewriting language all you need is the two lines above Okay, so what do I type those two lines into to implement that? How many lines of code does that involve? > more recently i implemented a term-rewriting language in i386 assembly, it's about 800 bytes and 400 instructions: http://canonical.org/~kragen/sw/dev3/qfitzah.s http://canonical.org/~kragen/sw/dev3/qfitzah.s but i haven't quite figured out how to handle arithmetic, i/o, and variadic lists Have you considered having a parameter stack that arithmetic operators pull their arguments from and push their results onto? Oh wait... ;-)