stdlibの基本オペレータの定義は組み込みで入ってるみたいですね。

import SwiftSyntax import SwiftParser import SwiftOperators var opPrecedence = OperatorTable.standardOperators // Use the Swift standard library operators let parsed = Parser.parse(source: "x + y * z") dump(parsed) // contains SequenceExprSyntax(x, +, y, *, z) let folded = try opPrecedence.foldAll(parsed) dump(folded) // contains InfixOperatorExpr(x, +, InfixOperatorExpr(y, *, z))

(edited)