testing/debugging grammar interactively ?

[asmodehn]

I am thinking something along the lines of https://omrelli.ug/nearley-playground/
that provides an interactive feedback to the user creating a grammar, via examples or other way.
The nicest tool I know is about regular expressions only : https://regex101.com/

Is there something like that for parser grammars ? where we could just add lark syntax?

I am not used to write parser grammars, and I am currently doing this in a python interpreter. The raw python error messages can be quite cryptic for a newcomer.
Any idea ? Am I missing an obvious tool here ?

[erezsh]

Sorry, there isn't an interactive tool for Lark.

Lark does have syntax highlighting for sublime-text, so you could use it to edit the grammar file and load it from the interpreter (it would probably be more convenient than writing the grammar in the interpreter).

[erezsh]

It should probably be pretty simple to fork nearley-playground and change the syntax to Lark's. It could be a nice addition to the lark toolbox.

[asmodehn]

I am already using sublime for syntax highlighting. Syntax is usually correct, but I guess I'm getting trapped into all the non obvious cases (using this parser fails, but why ?).

Related "feature request" issue is at lark-parser/lark_syntax#2

We probably would want to run Lark (python code) in the browser, somehow... Just to make sure we are actually testing lark while using it, and providing a strong guarantee for the grammar one would copy/paste between web page and lark file...

Let me know if you have any preference for a Browser Python implementation ( brython, skulpt, etc.) I might give it a try sometime...

[asmodehn]

Just for the record, and maybe inspiration, the two best tools I could find around the net :

• https://mdaines.github.io/grammophone
• https://web.stanford.edu/class/archive/cs/cs103/cs103.1156/tools/cfg/

[erezsh]

The first one seems nice, but a little primitive. Ideally, you'd have syntax highlighting, proper error handling, and a display of the resulting tree (when given an input).

I don't have experience with brython or skulpt, or alternatives, so I'll leave it to whoever chooses to implement it. I can say that from a cursory glance, brython seems like the best choice.

[erezsh]

Now that Lark has an online IDE, this should be easier to implement: https://lark-parser.github.io/lark/ide/app.html new link: https://www.lark-parser.org/ide/

[asmodehn]

Oh the online IDE is very nice indeed ! Sadly, I probably won't have time to come back to this in the near future though, but I ll give it a spin whenever I can.

[enjoysmath]

Now that Lark has an online IDE, this should be easier to implement: https://lark-parser.github.io/lark/ide/app.html

Never loads, mon! :>

[erezsh]

Sorry, that's an old link! New link is https://www.lark-parser.org/ide/

[erezsh]

P.S. @enjoysmath You should be able to share the same Lark instance with as many modules that you want. As long as you use the documented API, it should work fine.

[enjoysmath]

I asked in the Django forums, but was unable to get a clear answer. What about Lark in a Django application? Do I create an instance for every user in their request.session?

…

On Wed, May 17, 2023 at 8:04 AM Erez Shinan ***@***.***> wrote: P.S. @enjoysmath <https://github.com/enjoysmath> You should be able to share the same Lark instance with as many modules that you want. As long as you use the documented API, it should work fine. — Reply to this email directly, view it on GitHub <#149 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAMIF56WIHFX7LGIX6EEILDXGTSHFANCNFSM4FBC6WTQ> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[erezsh]

@enjoysmath I don't remember Django well enough, but if it's technically possible to share the same Lark instance, I don't see a reason not to.