Technically, the opening brace is needed in C to support K&R style function declarations which apparently were still legal in C11 at least, but I doubt that's a feature anyone wants to replicate in a new language.

Not in the original C, where you had to declare function parameter types like so:

  int foo(x)
    int x;
  {
      return x;
  }

and not in C23 (or GNU C) either, where this is legal (this example is not super useful):

  int foo(int x) [[gnu::aligned]] {
    return x;
  }

In that case, I would prefer Pascal’s (and Basic’s) “end”, however.

Unmatched braces completely mess up text editors, which would need to include a full parser in order to pair-match brackets (it also creates an unresolved tension that will stay with you all day :)

I was going to say the same. And yes - it causes OCD in 90% of devs out there. But it also feels somewhat wrong for editors to match brackets to infer block hierarchy. What if blocks have some sane rule that we don't know yet (i.e other than bracketed blocks and indented blocks)? Perhaps treesitter is the one-stop solution for that problem.

Indeed. Things like di{ probably don't work...

> :)

That’s a mouth, not a paren :/ I won’t be able to sleep tonight :)) (that’s better

Many languages are designed with IDEs in mind and "dumb" text editors are not a concern.

Text editors need fairly complete parsers to match braces anyway. E.g. consider even something as simple as { "}" }. Or {"\"}. The former is reasonably unambiguous, but the latter requires knowing if the escape style of double quoted strings in the given language escapes the second '"' or not. Now try proc {"#{"}"}"} (valid Ruby) vs proc {"{\#{"}"}"} (invalid)

I have an even better idea:

  main(): int
    printf "hello"
    0

;)

Trouble with that is invoking main and declaring main are too similar. I prefer this:

    let main () =
      printf "hello"
      0

Why do we put spaces after punctuation in English?It's completely redundant.actually,why even put a capital letter at the beginning of a sentence?it can obviously be inferred.

OK, I'll stop now, but the point is: matching braces provide visual structure that's helpful to read code, even if it's syntactically redundant.

Prose is not a programming language, isn't it obvious?

One is designed for machines to parse unambiguously, the other has grown organically and chaotically over hundreds of years. Machine parsing has never been a design concern.

Indentation provides visual structure. Matching braces hardly add value to it.

You identified its purpose: symmetry.