[aurelius]

The point is that lisp advocates rarely seem to use any of these lisp implementations to do anything noteworthy or useful. They always seem to fall back on C, or some other language that's more "widely available" or "has minimal dependencies" or "has more potential contributors" or "can be more easily compared with other similar programs".

I find this hypocrisy to be quite intriguing.

[lispm]

> The point is that lisp advocates rarely seem to use any of these lisp implementations to do anything noteworthy or useful.

That's possible. There are many Lisp dialects and implementations which have few applications. That's true for a lot of other language implementations, too. There are literally thousands implementations of various programming languages with very few actual applications. Maybe it is fun to implement your own language from the ground up. Nothing which interest me, but it does not bother me.

If he wants to implement a small new Lisp dialect its perfectly fine to implement it in C or similar.

> They always seem to fall back on C, or some other language that's more "widely available" or "has minimal dependencies" or "has more potential contributors" or "can be more easily compared with other similar programs".

Some new dialect is written with the help of C? That bothers you?

Wow.

Actually 95% of all Lisp systems contain traces of C and some are deeply integrated in C or on top of C (CLISP, ECL, GCL, CLICC, MOCL, dozens of Scheme implementations and various other Lisp dialects). There are various books about implementing Lisp in C.

Really nobody in the Lisp community loses any sleep that somebody implements parts of Lisp in C.

> I find this hypocrisy to be quite intriguing.

Because some random guys implement their own language in C? Why do we have Python, Ruby, Rebol? There was already PERL or AWK or ... Somebody decided to write their own scripting language. So what?

[aurelius]

> Because some random guys implement their own language in C? Why do we have Python, Ruby, Rebol? There was already PERL or AWK or ... Somebody decided to write their own scripting language. So what?

When a Python advocate wants to do some data processing, do they first write their own Python implementation in C? No. When a Ruby advocate wants to make a Rails website, do they first write their own implementation of Ruby in C? No.

Several fine implementations of lisp already exist that compile down to machine code and, if the lisp community is to believed, have performance "close to C". So why does a lisp advocate feel the need to re-write lisp in C for a project that didn't actually need it? The lisp community would have us all believe that lisp is the "programmable programming language", and all the other rhetoric about how every other language has just stolen ideas from lisp, etc., etc.. They all truly seem to believe that lisp is something special. That's why I find it laughable that someone like Kaz Kylheku, a 15 year veteran of comp.lang.lisp, decided not to implement TXR by using a pre-existing lisp implementation.

[lispm]

> When a Python advocate wants to do some data processing, do they first write their own Python implementation in C?

They write it in C. Checkout the Python world sometimes.

* CrossTwine Linker - a combination of CPython and an add-on library offering improved performance (currently proprietary)

* unladen-swallow - "an optimization branch of CPython, intended to be fully compatible and significantly faster", originally considered for merging with CPython

* IronPython - Python in C# for the Common Language Runtime (CLR/.NET) and the FePy project's IronPython Community Edition

* 2c-python - a static Python-to-C compiler, apparently translating CPython bytecode to C

* Nuitka - a Python-to-C++ compiler using libpython at run-time, attempting some compile-time and run-time optimisations. Interacts with CPython runtime.

* Shed Skin - a Python-to-C++ compiler, restricted to an implicitly statically typed subset of the language for which it can automatically infer efficient types through whole program analysis

* unPython - a Python to C compiler using type annotations

* Nimrod - statically typed, compiles to C, features parameterised types, macros, and so on

and so on...

> So why does a lisp advocate feel the need to re-write lisp in C for a project that didn't actually need it? The lisp community would have us all believe that lisp is the "programmable programming language"

Why don't you understand the difference between 'a lisp advocate' and 'the lisp community'?

> nd all the other rhetoric about how every other language has just stolen ideas from lisp, etc., etc..

Nonsense.

> That's why I find it laughable that someone like Kaz Kylheku, a 15 year veteran of comp.lang.lisp, decided not to implement TXR by using a pre-existing lisp implementation.

I find it laughable that you find it laughable...

[aurelius]

Every single Python project you stated simply proves my point. They are Python compilers of some sort. TXR, on the other hand, is a data processing language implemented in its own lisp which is implemented in C. In other words, TXR is an application of lisp, not just a compiler or interpreter like those Python projects you listed. So, all your examples are irrelevant.

TXR didn't need its own dialect of lisp. So, the question remains: why didn't Kaz use SBCL or CLISP? They're good enough for c.l.l. kooks like him to recommend to everyone else, but why're they not good enough for him to use?

[kazinator]

The kook here is you, and I can prove it: you have a bizarre view that developers should be divided into political parties based on programming language, and code strictly to the party lines. Bizarre views make the kook.

TXR does need its own dialect of Lisp because Common Lisp isn't suitable for slick data munging: not "out of the box", without layering your own tools on top of it.

This is a separate question from what TXR is written in. Even if TXR were written using SBCL, it would still have that dialect; it wouldn't just expose Common Lisp.

That dialect is sufficiently incompatible that it would still require writing a reader and printer from scratch, and a complete code walker to implement the evaluation rules of the dialect. Not to mention a reimplementation of most of the library. The dialect has two kinds of cons cells, so we couldn't use the host implementation's functions that understand only one kind of cons cell. So, whereas some things in TXR Lisp could be syntactic sugar on top of Common Lisp, with others it is not so.

Using SBCL would have many advantages in spite of all this, but it would also reduce many opportunities for me to do various low-level things from scratch. I don't have to justify to anyone that I feel like make a garbage collector or regex engine from scratch.

So, the reasons for not using "SBCL" have nothing to do with "good enough". It's simply about "not mine".

TXR is a form of Lisp advocacy.

TXR is also (modest) Lisp research; for instance I discovered a clean, workable way to have Lisp-1 and Lisp-2 in the same dialect, so any Lispers who are paying attention can stop squabbling over that once and for all.

It pays to read this:

http://www.dreamsongs.com/Files/HOPL2-Uncut.pdf

Why we have Lisp today with all the features we take for granted is that there was a golden era of experimentation involving different groups working in different locations on their own dialects. For example, the MacLisp people hacked on MacLisp, and it wasn't because Interlisp wasn't good enough for them. Or vice versa.

That experimentation should continue.

[aurelius]

> So, the reasons for not using "SBCL" have nothing to do with "good enough". It's simply about "not mine".

Kaz, the C programming language isn't yours either. My point is that Common Lisp is supposed to be a general purpose programming language with power far greater than a primitive language like C, but you chose to implement TXR in C simply because C makes it much easier for you to accomplish your goal than Common Lisp. I'm just trying to point out the obvious, which nobody from c.l.l. seems willing to admit.

[lispm]

It's a tool with some embedded kind of Lisp dialect. There are zillions of it.

> why didn't Kaz use SBCL or CLISP?

Why should he? He can do whatever he want. I personally don't care at all about what he does. Why are you? Kind of strange obsession with comp.lang.lisp. Are you one of the trolls posting there?

> They're good enough for c.l.l. kooks like him to recommend to everyone else, but why're they not good enough for him to use?

Probably he did it to annoy real programmers like you?

[aurelius]

> > why didn't Kaz use SBCL or CLISP?

> Why should he?

Kaz invested a bunch of time implementing a whole new backquote implementation for CLISP, but it's still not good enough for him to use CLISP to implement TXR? It doesn't make any sense!

Any right-thinking programmer should care about inconsistencies such as this. If I'm evaluating a programming language, and I see someone in its community writing their own language implementation to support an application that could've easily been written using one of the standard language implementations, then it looks to me like the standard implementations aren't mature enough or trustworthy enough for me to use for my application. Not only that, but it suggests that maybe this particular language isn't as good as its advocates claim, especially if I have to drop back down to C in order to meet certain requirements (e.g., portability, speed, wider understanding, etc.).

But any right-thinking programmer already knows that lisp is not worth wasting any time on. It's dead, and people like Kaz, and projects like TXR, are going to make sure it stays that way.