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Comment by commandlinefan | Hacker News Reader

> BrainF#*k not a true language

Curious why that might be, and TFA doesn't expound. What makes it not a "true" language?

Author here. You know it when you see it. LISP is a tool that people want to use. People write production software using it. For example, this website (Hacker News) was written in LISP. Languages like BrainFuck are usually only called programming languages if the word "esoteric" is attached. There's a real consensus of opinion around this this being a generally held view.

There should ideally be a more compelling explanation of why Brainfuck is an esoteric toy and LISP isn't, than me simply saying "but that's what people believe". I considered going into more depth on this subject. I found a C to Brainfuck compiler written in OCaml and used it to compile a Brainfuck metacircular evaluator into Brainfuck. It ended up being 88,439 bytes of code, and it sadly didn't work, because the compiler isn't very polished.

Let's compare ratios. Brainfuck is 99 bytes, whereas Brainfuck written in Brainfuck is 88439 bytes. That's 893x larger. On the other hand, LISP is 436 bytes of systems code and LISP written in LISP is 1370 bytes of LISP. That's 3.14x larger. It's cool that the ratio between layers of simulation with LISP is pretty close to pi. It helps explain why LISP is viewed by human beings as being such a powerful tool, since it lets you accomplish more impact with less effort, without having the castles you build turn into a leaning tower of pisa. Since after all, the purpose of tools since prometheus has been to give people more power.

Would you consider binary lambda calculus [1] [2] a real language? The 650 byte interpreter written in obfuscated C also sports garbage collection and might fit in a bootsector when translated to x86 code. Its metacircular interpreter is only 29 bytes (232 bits), and looks somewhat readable with some syntactic sugar [4] (analogous to how x86 looks more readable as assembler source).

[1] https://www.ioccc.org/2012/tromp/hint.html

[2] https://tromp.github.io/cl/Binary_lambda_calculus.html

[3] https://github.com/tromp/AIT/blob/master/int.lam

But does either include a JIT? Can they JIT themselves?

Counter argument: ever seen the proof for simple addition in English? The verbosity and/or opacity of the definition of a system isn't a great proxy for value or ease of use. Principia Mathematica uses over 1000 pages to reach the proof that 1+1=2, formally defining and explaining everything needed along the way, establishing fundamentals and primitive types and so on.

Brainfuck isn't a great interpreter language. It is a great perspective language. If you can break your tasks down sufficiently that you can express your program in brainfuck, you can take that understanding back to a more performant and expressive language. Doing Rosetta code exercises in esoteric languages forces your brain to model programs with more nuance and detail. If raw machine level performance was the only thing that mattered, we'd be writing everything in assembly. Different languages can have different utility, though, and while brainfuck is less useful as software, it is an excellent tool, not just a toy.

Isn't the distinction as simple as "does the language let you define anything and use recursion?", where I'm going to be a bit handwavy with "define anything" but I think we all get what I mean.

You can't name functions in Brainfuck or recursively call them. You can do so in LISP and Forth. That is also the entire reason Brainfuck explodes in size: it lacks the "semiotic" capabilities required to compress source code (and therefore, structure and refactor code, which is what humans need).

To me it's missing the point to describe that as Brainfuck versus Lisp. It just turns out that lambda functions and linked lists are higher level abstractions than arrays and pointers. I'd like to see some more variations on that concept and what the size is if using another esolang that has lambda functions.

I had this argument once -- I also believe Brainfuck is more of a machine than a language. Whereas Lisp is a language.

The main reason is that Brainfuck lacks composition, so what happens in practice is that people GENERATE Brainfuck code rather than writing it. When you write code, you rely heavily on your programming language's mechanisms for composition in order to make something that works.

Someone pointed me to people who DO actually program by hand in Brainfuck. There are some pretty big programs that are hand-written, not generated. Still I'm not entirely convinced, as they seem to be have been constructed through mental feats, not compositional language.

It's a curious fact that human languages and programming languages compose in a way that can be leveraged to build very large things that "work". I guess there is some equivalence between building up a large body of knowledge through language and making a program that works. Brainfuck doesn't seem to have this property.

The demonstrations of arithmetic and calculus in the post are nice examples of this in Lisp, and from there you have the rest of the world as your disposal (which is well documented in many books). With Brainfuck you're left crawling on your hands and knees, occasionally finding something that works, so to speak.

Brainfuck, like assembly and forth, composes by concatenation.

Data structures have to compose too

From the beginning of SICP [0]:

> A powerful programming language is more than just a means for instructing a computer to perform tasks. The language also serves as a framework within which we organize our ideas about processes. Thus, when we describe a language, we should pay particular attention to the means that the language provides for combining simple ideas to form more complex ideas. Every powerful language has three mechanisms for accomplishing this:

> * primitive expressions, which represent the simplest entities the language is concerned with,

> * means of combination, by which compound elements are built from simpler ones, and

> * means of abstraction, by which compound elements can be named and manipulated as units.

Brainfuck is missing any sort of means of abstraction. The primitives are instructions, and the only means of combination is writing instructions in sequence, but there's no way in the language to refer to any sequence of instructions --- no functions, no subroutines, not even labels. This makes it utterly useless as a way to organize your thoughts on how to compute something.

[0] http://sarabander.github.io/sicp/html/1_002e1.xhtml#g_t1_002...

It's almost the opposite of a language, in that it's probably harder to do anything with than just using whatever the native assembly instructions of the machine are. It's explicitly designed to be annoying, an example of a Turing tarpit:

https://en.wikipedia.org/wiki/Turing_tarpit

I would have to assume because it's neither a high-level language, nor a practical low-level one. True in the sense of a language being a labor-saving device.

Ok, that matches my understanding of it then - it is a language, just not one you'd actually want to do anything in. I was thinking that the author was saying it wasn't a programming language in the sense that HTML is not a programming language.

My "not so gracious" interpretation: "It would invalidate the claim that we wish to make, so... no true scotsman"

Author here. We anticipated this as a possible criticism of our "we built the world's tiniest programming language" claim. That's why we wrote the Brainfuck interpreter too. As far as I know, the 99 byte Brainfuck interpreter that's included in this blog post is the tiniest one to date. So even if that invalidates our tiny LISP victory, it'd still be a victory for the team since we built the competition too.

Lisp is a language that people actually use to get work done; Brainfuck isn't.

Well… I believe it was James Gosling who said that there are two types of computer languages: “ones people complain about and ones nobody uses”. So if you’re complaining about Brainfuck then it must be a language people use by process of elimination ; )

Stroustrup, not Gosling. And I like your logic. :)

This presumes that "ones people complain about" and "ones nobody uses" are mutually exclusive - and I'm reasonably sure that Brainfuck is clear evidence against such mutual exclusivity ;)

Unless your "work" is proving that a language is Turing complete. That is, to my knowledge, the only serious use of brainfuck.

I suppose the humor was lost in my message.

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