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Parser-generators were always academic projects that had little relevance to making real-world programming languages -- where parsing is very easy to write, and

Parser-generators were always academic projects that had little relevance to making real-world programming languages -- where parsing is very easy to write, and necessarily benefits from doing it (ie., you can get better error handling/etc.). Today most languages are front-ends for LLVM IR, but LLVM is very slow and takes a long time to optimize. Many new languages target x86/arm directly with their own weakly optimized backends, and output an LLVM IR for "release builds".

sestep 2y ago
Could you give some specific examples of those new languages with their own backends for faster builds?
- mjburgess 2y ago
  I was immediately thinking of Jai, Zig, .. but I've seen a few
  - stefanos82 2y ago
    Correct me if I'm wrong, but I think both Zig and Jai use LLVM as their default backend...at least, that's what I have seen via live streaming for Jai, and from Zig's repo.
    - vulcan01 2y ago
      Zig is moving away from LLVM (https://github.com/ziglang/zig/issues/16270 https://github.com/ziglang/zig/issues/16270) and Rust has added Cranelift as a debug backend (https://lwn.net/Articles/964735/ https://lwn.net/Articles/964735/). Not sure about Jai.
      - stefanos82 2y ago
        I don't think it's moving away, because if you have read the entire thread, the gaming community reacts negatively to say the least and they assure everyone that LLVM does not going anywhere any time soon.
thechao 2y ago
When your computer was anemic, and could barely do the tasks required for it, eking out a few percent — or a 2x! — from an optimizer was important. Now-a-days, the difference between "big compiler optimized" and "little compiler not optimized" can be quite dramatic; but, is probably no more than 4x — certainly within range of the distinction between "systems programming language" and "high tuned JITted scripting language". I think most people are perfectly fine with the performance of highly-tuned scripting languages. The result is that all of the overhead of "big compiler" is just ... immaterial; overhead. This is especially true for the case of extremely well-tuned code, where the algorithm and — last resort — assembly, will easily beat out the best optimizer by at least an order-of-magnitude, or more.
- auselen 2y ago
  Wouldn’t just a simple case of bad code generation render little compiler into a toy one? Repeating others, today’s compilers are really just “optimizing compilers”, there is no room for toying in production environments.
  - fuhsnn 2y ago
    >just a simple case of bad code generation render little compiler into a toy one If you find some time to go through gcc bugzilla you'll find shockingly simple snippets of code that miscompiled (often by optimization passes), with fixes never backported to older versions that production environments like RHEL are using.
    - auselen 2y ago
      Ok, but that’s sw engineering issue. I still insist that a production grade compiler can’t leave performance on table. Which is where the current battlefield is.
      - jsnnsjxj 2y ago
        I do not agree in the general case. There are very useful DSL compilers which do not consider performance at all, but just compile to a target which does the optimization for them (JVM, LLVM IR or even just C)
Croftengea 2y ago
> Parser-generators were always academic projects Were they? GCC abandoned bison in favour of their own parser relatively recently.
- userbinator 2y ago
  "relatively recently" as in around 20 years ago, in GCC 3.x according to sources I found.
  - kragen 2y ago
    gcc was first released in 01987, but it didn't replace its bison parser for c until gcc 4.1 https://gcc.gnu.org/gcc-4.1/changes.html https://gcc.gnu.org/gcc-4.1/changes.html which was in 02006 https://gcc.gnu.org/releases.html https://gcc.gnu.org/releases.html, only 18 years ago, and 19 years after it was released. joseph myers first proposed doing this in 02004 https://gcc.gnu.org/legacy-ml/gcc-patches/2004-10/msg01969.html https://gcc.gnu.org/legacy-ml/gcc-patches/2004-10/msg01969.h... so gcc has literally been using a parser-generator-generated parser for c for more than half its existence, at which point it had already become the most popular c compiler across the unix world and basically the only one used for linux, which had already mostly annihilated the proprietary unix market. it was also imposingly dominant in the embedded space and i think that kind of development path is fairly typical; getting a parser up and running is easier with a parser generator, but it can be tricky to get it to do strange things when that's what you want (especially with lalr, less so with peg)
kragen 2y ago
yacc/bison was used for lex, bc, pcc, gcc, original awk, the bsd pascal compiler, eqn, m4 (!), and many other languages. it's still used for pcc, oawk, mawk, pari/gp, and units. that's just what i have sitting around in my downloads directory and, while we're talking about ocaml, ocaml does use ocamllex and ocamlyacc for its own parser so, while you can certainly do without parser generators, they have very commonly been used for making real-world programming languages. almost every programming language anyone here has ever heard of was first implemented with a parser generator. the main exceptions are probably fortran, cobol, algol, lisps, c, and pascal
- mjburgess 2y ago
  I guess I wasn't very clear. I didnt mean to say, as a historical matter, were irrelevant. I meant to say the idea of a parser generator is a solution to a problem that that real world langs don't really have. When writing a programming language, your issue isnt how much time the parser is going to take to write, or how complex it's going to be. The parser is a relatively trivial part of the problem. Due to language designers often being taught to develop langauges in this fashion, many have relied on these tools. But the modern view of compliers as "programming langauge UIs" and the focus on DX, i'd argue its actively pathological to use a parser generator. Much academic work has, til recently, focused on these areas -- whereas today, the bulk of the difficulty is in understanding SSA/LLVM/ARM/Basic Optimizatiosn/etc. details which are "boring, circumstantial" etc. and not really research projects. I was just pointing this out since a lot of people, myself included, go down the EBNF parser-generator rabbit hole and think inventing a langauge is some formal exercise -- when the reality is the opposite: it's standard programming-engineering work.
  - kragen 2y ago
    oh, i agree that parsing is not the hard part of writing a compiler, and that compilers classes overemphasize it but no language starts out as a 'real world lang'; every language is initially a toy language, and only becomes a 'real world lang' in the unlikely case that it turns out to be useful. and parser generators are very useful for creating toy languages. that's why virtually every real world lang you've ever used was implemented first using a parser generator, even if the parser you're using for it now is handwritten having a formally defined grammar is also very helpful for dx features like syntax highlighting and automated refactoring

sestep 2y ago

Could you give some specific examples of those new languages with their own backends for faster builds?

mjburgess 2y ago
I was immediately thinking of Jai, Zig, .. but I've seen a few
- stefanos82 2y ago
  Correct me if I'm wrong, but I think both Zig and Jai use LLVM as their default backend...at least, that's what I have seen via live streaming for Jai, and from Zig's repo.
  - vulcan01 2y ago
    Zig is moving away from LLVM (https://github.com/ziglang/zig/issues/16270 https://github.com/ziglang/zig/issues/16270) and Rust has added Cranelift as a debug backend (https://lwn.net/Articles/964735/ https://lwn.net/Articles/964735/). Not sure about Jai.
    - stefanos82 2y ago
      I don't think it's moving away, because if you have read the entire thread, the gaming community reacts negatively to say the least and they assure everyone that LLVM does not going anywhere any time soon.

thechao 2y ago

When your computer was anemic, and could barely do the tasks required for it, eking out a few percent — or a 2x! — from an optimizer was important. Now-a-days, the difference between "big compiler optimized" and "little compiler not optimized" can be quite dramatic; but, is probably no more than 4x — certainly within range of the distinction between "systems programming language" and "high tuned JITted scripting language". I think most people are perfectly fine with the performance of highly-tuned scripting languages. The result is that all of the overhead of "big compiler" is just ... immaterial; overhead. This is especially true for the case of extremely well-tuned code, where the algorithm and — last resort — assembly, will easily beat out the best optimizer by at least an order-of-magnitude, or more.

auselen 2y ago
Wouldn’t just a simple case of bad code generation render little compiler into a toy one? Repeating others, today’s compilers are really just “optimizing compilers”, there is no room for toying in production environments.
- fuhsnn 2y ago
  >just a simple case of bad code generation render little compiler into a toy one If you find some time to go through gcc bugzilla you'll find shockingly simple snippets of code that miscompiled (often by optimization passes), with fixes never backported to older versions that production environments like RHEL are using.
  - auselen 2y ago
    Ok, but that’s sw engineering issue. I still insist that a production grade compiler can’t leave performance on table. Which is where the current battlefield is.
    - jsnnsjxj 2y ago
      I do not agree in the general case. There are very useful DSL compilers which do not consider performance at all, but just compile to a target which does the optimization for them (JVM, LLVM IR or even just C)

Croftengea 2y ago

> Parser-generators were always academic projects Were they? GCC abandoned bison in favour of their own parser relatively recently.

userbinator 2y ago
"relatively recently" as in around 20 years ago, in GCC 3.x according to sources I found.
- kragen 2y ago
  gcc was first released in 01987, but it didn't replace its bison parser for c until gcc 4.1 https://gcc.gnu.org/gcc-4.1/changes.html https://gcc.gnu.org/gcc-4.1/changes.html which was in 02006 https://gcc.gnu.org/releases.html https://gcc.gnu.org/releases.html, only 18 years ago, and 19 years after it was released. joseph myers first proposed doing this in 02004 https://gcc.gnu.org/legacy-ml/gcc-patches/2004-10/msg01969.html https://gcc.gnu.org/legacy-ml/gcc-patches/2004-10/msg01969.h... so gcc has literally been using a parser-generator-generated parser for c for more than half its existence, at which point it had already become the most popular c compiler across the unix world and basically the only one used for linux, which had already mostly annihilated the proprietary unix market. it was also imposingly dominant in the embedded space and i think that kind of development path is fairly typical; getting a parser up and running is easier with a parser generator, but it can be tricky to get it to do strange things when that's what you want (especially with lalr, less so with peg)

kragen 2y ago

yacc/bison was used for lex, bc, pcc, gcc, original awk, the bsd pascal compiler, eqn, m4 (!), and many other languages. it's still used for pcc, oawk, mawk, pari/gp, and units. that's just what i have sitting around in my downloads directory and, while we're talking about ocaml, ocaml does use ocamllex and ocamlyacc for its own parser so, while you can certainly do without parser generators, they have very commonly been used for making real-world programming languages. almost every programming language anyone here has ever heard of was first implemented with a parser generator. the main exceptions are probably fortran, cobol, algol, lisps, c, and pascal

mjburgess 2y ago
I guess I wasn't very clear. I didnt mean to say, as a historical matter, were irrelevant. I meant to say the idea of a parser generator is a solution to a problem that that real world langs don't really have. When writing a programming language, your issue isnt how much time the parser is going to take to write, or how complex it's going to be. The parser is a relatively trivial part of the problem. Due to language designers often being taught to develop langauges in this fashion, many have relied on these tools. But the modern view of compliers as "programming langauge UIs" and the focus on DX, i'd argue its actively pathological to use a parser generator. Much academic work has, til recently, focused on these areas -- whereas today, the bulk of the difficulty is in understanding SSA/LLVM/ARM/Basic Optimizatiosn/etc. details which are "boring, circumstantial" etc. and not really research projects. I was just pointing this out since a lot of people, myself included, go down the EBNF parser-generator rabbit hole and think inventing a langauge is some formal exercise -- when the reality is the opposite: it's standard programming-engineering work.
- kragen 2y ago
  oh, i agree that parsing is not the hard part of writing a compiler, and that compilers classes overemphasize it but no language starts out as a 'real world lang'; every language is initially a toy language, and only becomes a 'real world lang' in the unlikely case that it turns out to be useful. and parser generators are very useful for creating toy languages. that's why virtually every real world lang you've ever used was implemented first using a parser generator, even if the parser you're using for it now is handwritten having a formally defined grammar is also very helpful for dx features like syntax highlighting and automated refactoring