Treesetter优先级未生效

Question

我正在学习如何使用树保姆，并制定语法来解析简单的谓词逻辑。很明显，我需要优先权来使否定~比连接和断开(/和/(结合得更紧密。我认为我已经正确地应用了优先级，实际上是复制了文档中的示例。

语法如下：

module.exports = grammar({
name: 'Predicate_Calculus',
rules: {
// TODO: add the actual grammar rules
source_file: $ => repeat($._expression),
_expression: $ => choice($.identifier,
$._unary_expression,
$._binary_expression,
seq('(', $._expression, ')')),
_binary_expression: $ => choice(
$.and,
$.or
),
_unary_expression: $ => prec(2, choice(
$.not
)),
not: $ => seq('~', $._expression),
and: $ => prec.left(seq($._expression, "/\", $._expression)),
or: $ => prec.left(seq($._expression, "\/", $._expression)),
identifier: $ => /[a-z_]+/
}
});

然而，当我运行tree-sitter generate时，我得到了这个错误：

╰─➤ tree-sitter generate
Unresolved conflict for symbol sequence:
'~'  _expression  •  '/'  …
Possible interpretations:
1:  '~'  (and  _expression  •  '/'  _expression)  (precedence: 0, associativity: Left)
2:  (not  '~'  _expression)  •  '/'  …
Possible resolutions:
1:  Specify a higher precedence in `and` than in the other rules.
2:  Specify a higher precedence in `not` than in the other rules.
3:  Specify a left or right associativity in `not`
4:  Add a conflict for these rules: `not`, `and`

我相信我对prec(2 choice($.not))所做的是选项2，但它在语法中似乎并不有效。我使用的是通过cargo安装的tree-sitter0.20.7。

Answer 1

好吧，在尝试了更多的排列之后，我发现将优先级指令移动到not定义中可以解决这个问题。

_unary_expression: $ => choice(
$.not
),
not: $ => prec(2, seq('~', $._expression)),

从_unary_expression中删除优先级，并将其移动到not内部。