Just a Comment

[ChayimFriedman2]

I've read your article https://calebschoepp.com/blog/2020/adding-a-list-data-type-to-lox/. Nice 😃.

One note, however: your grammar is incorrect. Specifically, your precedence is incorrect. Subscripting should be the same precedence as call (and property access). You should replace:

call           → subscript ( "(" arguments? ")" | "." IDENTIFIER )* ;
subscript      → primary ( "[" logic_or "]" )* ;

With:

call           → subscript ( "(" arguments? ")" | "." IDENTIFIER | "[" logic_or "]" )* ;

Otherwise, an expression like f()[0] won't be valid. I would also change the thing inside the brackets to expression, like parentheses (most languages do so), but the choice is yours 😃.

Also, you duplicate the rule unnecessarily: in your assignment rule, you need just one bracket (the asterisk is redundant). Instead of:

assignment     → ( call "." )? IDENTIFIER ( "[" logic_or "]" )* "=" assignment
               | logic_or ;

Do:

assignment     → ( ( call "." )? IDENTIFIER | ( "[" logic_or "]" ) ) "=" assignment
               | logic_or ;

Because an expression like a[0][0] = 0 can emit normally for the a[0], just the [0] = 0 at the end needs special handling.

Yeah, designing a language is hard 😄. This is the reason I always look for "what other languages do", preferably their EBNF, when writing my own EBNF.

Disclaimer: I haven't read your code, just your EBNF syntax.