How to extract grammar from cst parser with embedded rules

[nomuna]

I have a parser that extends the cst parser with embedded grammar rules.

I am trying to extract the grammar as json object but it is giving me an empty object what am I doing wrong?

[nomuna]

Yeah I found my issue. Somebody extracted the grammar in a method outside of the constructor and was calling it later in a code.
Reason being apparently that the parser has to be a singleton...

[bd82]

Hello @nomuna

I am not sure exactly what was your issue, but regarding the Parser as a singleton.
It is not mandatory but highly recommended due to performance reasons.

• https://chevrotain.io/docs/guide/performance.html#using-a-singleton-parser

[nomuna]

thanks for the info.

No, they didn't do it the way it was shown in the documentation. They provided a classic singleton implementation with a static getParser() method that returns an instance and if you need the grammar to be loaded you need to call a method say parse() where all the grammar is initialized and then the performSelfAnalysis is called.