Lisp is an interesting point. I guess the argunent is that it's the right tool for every job?
Unix is a reasonable example of a polyglot environment, but at a high cost. Lots of serialization/deserialization through text. That has a high cost in terms of bugs, complexity, lines of code, and inefficiency.
> Lisp is an interesting point. I guess the argunent is that it's the right tool for every job?
Yup, that's more or less the argument, though the argument need not only apply to lisp.
> Unix is a reasonable example of a polyglot environment, but at a high cost.
I'd rather say that Unix is an example of how to effectively drive down the cost of a polyglot environment to a point where it is outweighed by the benefits.
Now, of course the cost is still there, but I would argue that beyond a certain scale you cannot optimize globally on a single runtime (perhaps not even with something like lisp) and so the cost of global consistency is outweighed by cost of being unable to optimize locally.
To put it more succintly, you could not build a system as complex as Unix in a single language[1]
[1] Although Ala Kay's work at VPRI suggests you can, if you choose a sufficiently expressive base language. But even that may have it's limits.
Unix is a reasonable example of a polyglot environment, but at a high cost. Lots of serialization/deserialization through text. That has a high cost in terms of bugs, complexity, lines of code, and inefficiency.