parser-demo VS grammars-v4

I have a demo project that fixes a lot of the default insanities.

I have an old demo project that demonstrates most of that for flex/bison, but this is C/C++ oriented so might not be super applicable for you.

It's just unfortunate that flex and bison have bad defaults due to historical compatibility with lex and yacc. If you're using them I have a demo project that tweaks the defaults toward sanity, though I haven't updated it for recent warnings.

I made a demo project that ties them together. I'm pretty sure at least one of the fixes was due to header cycle problems, but I haven't touched it for a while. (note also that the demo was fully warning-clean at the time, but there may be new warnings since)

I made a demo project that avoids several historical annoyances with Flex and Bison - in particular, I made it warnings-clean (though I haven't updated it recently), and I avoid global state.

I have a demo project that enables all of the non-default options that you really should be using in all new projects. Note that the demo doesn't demonstrate meaningful grammars, just shows how to arrange the surrounding code and makefile.

I have a demo project that twiddles most of the important knobs.

Bash is a really complicated language. Redirections and such are simple; they are just tokenization, and any lexer/parser tutorial should get you there (I have a demo project using flex/bison).

Bison can be configured to avoid every single one of those problems. I use reentrant versions (both with and without push parsing) in my demo project. I admit I didn't bother with named references or cleaning up after errors.

a lot of the things that people hate about flex/bison is actually just their defaults for compatibility with lex/yacc, which can be changed. I have a demo project that does some of the things: https://github.com/o11c/parser-demo

Perhaps the one from ANTLR's collection [0] is a good start (there are also others ANTLR VB6 grammars documented elsewhere). It does require knowing ANTLR, but that should be less effort for someone already familiar with language implementation, particularly, the visitor pattern (my favorite reference [1]).

[0] https://github.com/antlr/grammars-v4/tree/master/vb6

[1] https://craftinginterpreters.com/representing-code.html

Where is the SQLite test suite, please? I'd be very interested.

There are already SQL grammars, check https://github.com/antlr/grammars-v4 specifically in here I think https://github.com/antlr/grammars-v4/tree/master/sql I contributed to one of them, and I wrote my own for some personal work. Be warned, it's very involved, very complex and MSSQL is rather ill-defined.

Names bracket identifiers) in SQL are bloody awful. Sometimes square brackets are even compulsory, and why you can usually replace [...] with the SQL standard "..." , not always! Trust me, it gets worse.

I don't find antlr grammars to be brittle, and while they can lose in performance (by how much I don't know, perhaps quite considerably) they are very easy to maintain and I am very fortunate to have antlr to work with.

This grammar "library" was cited as an example of what the format could look like:.

https://github.com/antlr/grammars-v4

There is everything from assembly and C++ to glsl and scripting languages, arithmetic, games, and other weird formats.

> Which brings me to the other approach: steering the LLM's output __as it is generating tokens__

A relevant PR:

https://github.com/ggerganov/llama.cpp/pull/1773

The plan is to support arbitrary grammar files to constrain tokens as they are generated, like the ones here:

https://github.com/antlr/grammars-v4

Have a look at jooq - I know this has been used to rewrite SQL from one dialect to another, so it MUST be capable of collating code activity metrics. Look here. Otherwise, you might want to look into writing your own parser. ANTLR has a T-SQL dialect parser script here.

Find a Perl grammar file for ANTLR, like https://github.com/antlr/grammars-v4/tree/master/perl Save the grammar file as Perl.g4 in your project. Now, you can create the Kotlin program: import org.antlr.v4.runtime.* import org.antlr.v4.runtime.tree.ParseTree import java.io.File

Antlr is another option. You could generate a parser using the JSON antlr grammar.