tree-sitter-rhai/grammar.js

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const PREC = {
range: 15,
call: 14,
field: 13,
unary: 12,
cast: 11,
multiplicative: 10,
additive: 9,
shift: 8,
bitand: 7,
bitxor: 6,
bitor: 5,
comparative: 4,
and: 3,
or: 2,
assign: 0,
closure: -1,
};
module.exports = grammar({
name: "rhai",
externals: ($) => [
$._string_content,
$.raw_string_literal,
$.float_literal,
$.block_comment,
],
extras: (_) => [/\s/],
word: ($) => $.identifier,
inline: ($) => [$._declaration_statement],
supertypes: ($) => [
$._expression,
$._literal,
$._literal_pattern,
$._declaration_statement,
$._pattern,
],
rules: {
source_file: ($) => repeat($._statement),
// statements
_statement: ($) => choice($.expression_statement, $._declaration_statement),
expression_statement: ($) => choice(seq($._expression, ";")),
_declaration_statement: ($) => choice($.let_declaration),
let_declaration: ($) =>
seq(
"let",
field("pattern", $._pattern),
optional(seq("=", field("value", $._expression))),
";"
),
// patterns
_pattern: ($) => choice($._literal_pattern, $.identifier, "_"),
// expressions
_expression: ($) =>
choice($.assignment_expression, $._literal, prec.left($.identifier)),
assignment_expression: ($) =>
prec.left(
PREC.assign,
seq(field("left", $._expression), "=", field("right", $._expression))
),
// literals
_literal: ($) =>
choice($.string_literal, $.raw_string_literal, $.integer_literal),
_literal_pattern: ($) =>
choice($.string_literal, $.raw_string_literal, $.integer_literal),
integer_literal: (_) => token(seq(choice(/[0-9][0-9_]*/))),
string_literal: ($) => seq(
alias(/b?"/, '"'),
repeat(choice($.escape_sequence, $._string_content)),
token.immediate('"')
),
escape_sequence: (_) =>
token.immediate(
seq(
"\\",
choice(
/[^xu]/,
/u[0-9a-fA-F]{4}/,
/u{[0-9a-fA-F]+}/,
/x[0-9a-fA-F]{2}/
)
)
),
// identifiers
identifier: ($) => /(r#)?[_\p{XID_Start}][_\p{XID_Continue}]*/,
},
});