internal
fun FlyweightCapableTreeStructure<LighterASTNode>.getFirstChildExpressionUnwrapped(node: LighterASTNode): LighterASTNode? {
    val firstChild = children(node).firstOrNull { it: LighterASTNode -> it.isExpression() } ?: return null
    return if (firstChild.tokenType == PARENTHESIZED) {
        getFirstChildExpressionUnwrapped(firstChild)
    } else {
        firstChild
    }
}


internal