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Asked: 2026-05-31T21:56:11+00:00

I got interested in parser generators. But I don’t have the theoretical background. I

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I got interested in parser generators. But I don’t have the theoretical background. I just read a few things on the internet.

Currently I’m trying to do something with ANTLR

So my questions:

I have a special format of my dataframes:

  • The first byte of a frame is a tag that describes the nature of the data
  • The second byte contains the length (number of bytes) of the data itself
  • Then follows the data itself
  • The data can contain dataframes itself, and dataframes can be listed one after the other

I hope my description is clear. My questions:

Can I create such a parser with ANTLR that reads the lengs of the frame and then knows when the frame ends?

In ANTLR can I load the different tags I use from a generated file?

Thank you!

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1 Answer

  1. Editorial Team

    I’m not 100% sure about this, but:

    • Parser generators like antlr require a grammar that is at least context-free
    • using length-fields in your data makes your grammar not context free (context-sensitive i think)

    It is the latter point i’m not sure about – maybe you want to research some more on that.

    You probably have to write a packet “parser” yourself (which then has to be a parser for your context-sensitive packet grammar)

    Alternatively, you could drop the length field, and use something like s-expressions, JSON or xml; these would be parseable by something generated with antlr.

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