Consider making `else_clause` an explicit node

[DavisVaughan]

tree-sitter-r/grammar.js

Lines 253 to 257 in 2097fa5

	optional(seq(
	$._else,
	repeat($._newline),
	field("alternative", $._expression)
	))

i.e. the seq(else, newlines, alternative) all wrapped up in a named node

This would be for air, which does make a distinction of the else_clause, and I think we could basically remove this whole section if we had a named node here
https://github.com/posit-dev/air/blob/ca6648d251d11a08041be4796b55f02e5d35f2cc/crates/air_r_parser/src/parse.rs#L770-L801

[DavisVaughan]

If we did something like this it would look like this

    if_statement: $ => withPrec(PREC.IF, seq(
      "if",
      repeat($._newline),
      field("open", $._open_parenthesis),
      field("condition", $._expression),
      field("close", $._close_parenthesis),
      repeat($._newline),
      field("consequence", $._expression),
      // No `repeat($._newline)` here. Specially handled in the scanner instead.
      optional(field("else_clause", $.else_clause))
    )),

    else_clause: $ => seq(
      $._else,
      repeat($._newline),
      field("alternative", $._expression)
    ),

But I'm not sure it is worth it. It would be nice for Air where we iterate over every individual token/node, but the ergonomics are already pretty good for Ark where we use child_by_field_name("alternative") to see if there is an else clause, which seems pretty good.

We've already worked around this in a fairly reasonable way in Air, so it's not a huge deal for that.

While many other grammars do have a separate else_clause node, I noted that go does not, so that makes me feel ok with keeping it as is https://github.com/tree-sitter/tree-sitter-go/blob/5e73f476efafe5c768eda19bbe877f188ded6144/grammar.js#L554

[gn0]

An unfortunate side-effect of the lack of an else_clause is that nvim-treesitter-context wrongly reports that the buffer is showing the if branch when the buffer is actually showing the else branch.

The line on which else occurs cannot be extracted from the if_statement node with a Tree-sitter query by nvim-treesitter-context:

(if_statement
  consequence: (_) @context.end
) @context

[DavisVaughan]

Interesting point, here's Rust's query for example
https://github.com/nvim-treesitter/nvim-treesitter-context/blob/59f318a65d42a5c4037796886a8874fd57f774fc/queries/rust/context.scm#L2-L9

I'll reopen to reconsider