feat(expression): implement binary operation parser with support for …

[LiYulin-s]

I wrote a table driven parser for expressions, introducing binaryOp, a utility for automatically generating expression parsers based on a table of operators, precedence, and associativity. It is heavily inspired by Parsec's buildExpressionParser.

[Hejsil]

I have not thoroughly read through all the code, so my understanding is a bit limited, but what are the benefits here compared to the examples/math.zig?

[LiYulin-s]

Compared to the math.zig example, this is designed as a reusable, strongly-typed parsing framework rather than a one-off grammar. It lets you define operator precedence and associativity explicitly, supports prefix/postfix/infix forms, and rigorously enforces operator signatures at compile time. While the math example is great for learning, a manual approach becomes harder to maintain and avoid left-recursion once a parser grows beyond basic arithmetic. This PR scales much better when adding new operators or semantics. :-)

[Hejsil]

avoid left-recursion

Well, the math example doesn't avoid left recursion because the recursiveRef is able to handle that case. Anyways I'll see I'll need to have a proper look at this at some pointer later and think about it

[LiYulin-s]

fine <3

[Hejsil]

Alright, had a look around and I'm not really convinced this is the way to go for mecha. Sorry to let your hard work go to waste. I've creating and issue where the API can be discussed: #104