public void Parser_UnaryExpression_HonorsPrecedences(SyntaxKind unaryKind, SyntaxKind binaryKind)
{
var unaryPrecedence = SyntaxInfo.GetUnaryOperatorPrecedence(unaryKind);
var binaryPrecedence = SyntaxInfo.GetBinaryOperatorPrecedence(binaryKind);
var unaryText = SyntaxInfo.GetText(unaryKind);
var binaryText = SyntaxInfo.GetText(binaryKind);
Debug.Assert(unaryText != null);
Debug.Assert(binaryText != null);
var text = $"{unaryText} a {binaryText} b";
var expression = ParseExpression(text);
using var e = new AssertingEnumerator(expression);
if (unaryPrecedence >= binaryPrecedence)
{
// binary
// / \
// unary b
// |
// a
e.AssertNode(SyntaxKind.BinaryExpression);
e.AssertNode(SyntaxKind.UnaryExpression);
e.AssertToken(unaryKind, unaryText);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.Identifier, "a");
e.AssertToken(binaryKind, binaryText);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.Identifier, "b");
}
else
{
// unary
// |
// binary
// / \
// a b
e.AssertNode(SyntaxKind.UnaryExpression);
e.AssertToken(unaryKind, unaryText);
e.AssertNode(SyntaxKind.BinaryExpression);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.Identifier, "a");
e.AssertToken(binaryKind, binaryText);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.Identifier, "b");
}
}