The thing is, the closest thing to append-only you have with ordinary programming languages APL and it's variants, where you can construct powerful functions wi

The thing is, the closest thing to append-only you have with ordinary programming languages APL and it's variants, where you can construct powerful functions with powerful primitives and methods for combining them. But the thing is that APL quickly becomes a "write only" language - as far as I know, the main use of APL someone sitting at a brockerage who can cobble together any algorithm on twenty minutes and often throws away the result afterwards. Which is to say, Unison is interesting because it seems to underestimate the importance of a program's code as document, as complete, coherent, human-readable, single-view, intentionally created text. Why hasn't the stream of ascii been replaced as the format of program in the last twenty years? It's a good question but the answer isn't that it's just matter of conservatism. There are several other things involved.