Re: [PATCH olang v1] spec: ebnf: add binary expressions

["Carlos Maniero" <carlos@maniero.me>]

>  (* Expressions *)
> -<expression>          ::= <integer> | <identifier>
> +<expression>                ::= <binary-expression>
> +<binary-expression>         ::= <logical-or-expression>
> +<logical-or-expression>     ::= <logical-and-expression> (<ows> '||' <ows> <logical-and-expression>)*
> +<logical-and-expression>    ::= <bitwise-or-expression> (<ows> '&&' <ows> <bitwise-or-expression>)*
> +<bitwise-or-expression>     ::= <bitwise-xor-expression> (<ows> '|' <ows> <bitwise-xor-expression>)*
> +<bitwise-xor-expression>    ::= <bitwise-and-expression> (<ows> '^' <ows> <bitwise-and-expression>)*
> +<bitwise-and-expression>    ::= <cmp-eq-and-neq-expression> (<ows> '&' <ows> <cmp-eq-and-neq-expression>)*
> +<cmp-eq-and-neq-expression> ::= <cmp-lt-and-gt-expression> (<ows> ('==' | '!=') <ows> <cmp-lt-and-gt-expression>)*
> +<cmp-lt-and-gt-expression>  ::= <bitwise-shift-expression> (<ows> ('<' | '>') <ows> <bitwise-shift-expression>)*
> +<bitwise-shift-expression>  ::= <additive-expression> (<ows> ('<<' | '>>') <ows> <additive-expression>)*
> +<additive-expression>       ::= <multiplicative-expression> (<ows> ('+' | '-') <ows> <multiplicative-expression>)*
> +<multiplicative-expression> ::= <primary-expression> (<ows> ('*' | '/') <ows> <primary-expression>)*
> +<primary-expression>        ::= <integer>
> +                              | <identifier>
> +                              | '(' <ows>  <expression> <ows> ')'

I'd like to get your opinion: Is it really necessary to represent
precedence here? Some language specifications [1] chose to omit this
detail. I' more inclined to keep the spec as simple as possible, even if
it makes the behavior a bit unclear. I believe it's more important to
represent our grammar in the spec rather than precisely detail how
olang behaves. Alternatively, we could follow Go's approach; they kept
the spec simple and added explanatory text about the language's
behavior.

But again, I just wanna an opinion here, I'm totally OK following the
spec you wrote, because I know that I suck at understanding the
precedence climbing method. :-)


[1]: Golang EBNF: https://go.dev/ref/spec#Expression / Rust EBNF:
https://web.mit.edu/rust-lang_v1.25/arch/amd64_ubuntu1404/share/doc/rust/html/grammar.html#binary-operator-expressions