I feel a rant coming on...

This is a _fantastic_ article which should be read by anyone interested in stack languages.

Though it wasn't my first programming language, Forth was certainly the first programming language I loved. I read Starting Forth and was blown away by the elegance of the language and by how easily you could get the language to modify itself. It also started a fascination with stack languages that persists to this day.

However, when I tried to actually do anything useful with Forth, I kept banging my head against a wall. The typical problem is that stack juggling is just too hard for most problems, and even when it isn't, it's more work than just writing down an algebraic expression would be. Stacks work well for some problems, but evaluating arbitrary algebraic expressions isn't one. Why would I want to do that? asks the Forth zealot. Because I do! Because I don't want to have to worry that I won't be able to do that easily in the future when I do need to. So even though I've designed my own Forths and other stack languages since then, rule #1 is always: support local variables. Even if I don't need them, I want them. If you don't believe me, translate this problem into Forth or some other stack language in a clear, intuitive way without using local variables:

# python code to compute solutions of a**2*x + b*x + c == 0:
def solve_quadratic_equation(a, b, c):
# assume a >=0, no complex roots
d = math.sqrt(b * b - 4.0 * a * c)
return ((-b - d) / (2.0 * a), (-b + d) / (2.0 * a))

Three lines of code, completely transparent. Now see this thread: http://osdir.com/ml/lang.concatenative/2005-01/msg00023.html. You'll
see how difficult this is to do without local variables in a stack language. The reason is easy to spot: you are using values in a pretty random-access way, not in a streamed way. This is common in algebraic equations. And it's not stack-friendly.

Another thing I hate about pure Forth is that floating-point values, if they exist at all (they often don't) are put on a different stack, which means you have to duplicate all the operators with different names (I call this "operator underloading") and this can lead to hilariously obscure bugs because the two stacks are independent.

Basically, the attitude that the hard-core Forthers have reminds me of analogous statements that have been made about communism, or moonieism or whatever extreme -ism is promoted as the cure to all problems: if you are having problems, it's because you haven't gone far enough down the road yet. Only by committing 1000% to the approach will you ever get anything done. This is pure cult behavior.

And yet: Forth does have a valid and useful niche, in embedded systems, and it is a fascinating language, one well worth studying. But I don't think it's a coincidence that none of the software that people use everyday (other than very low-level stuff like e.g. the boot proms) on their computers is written in Forth.

Here's a challenge: I would really love to see someone write a full-featured web browser (at the level of a Firefox, Chrome or Safari) in Forth. You can do that in C, C++, Java, Python, and probably in dozens of other languages I could name. The beauty of this problem is that you can't go and bitch that you shouldn't have to support something like (say) CSS or embedded video because you think it's unnecessary; it's part of the problem domain and you don't get to complain about it. I think that any web browser that anyone attempted to write in Forth (without local variables, naturally!) would never get finished. But maybe I'm wrong, and I just haven't reached Forthlightenment yet. If so, prove me wrong.