public void Parser_UnaryExpression_HonorsPrecedences(SyntaxKind unaryKind, SyntaxKind binaryKind)
{
var unaryPrecedence = unaryKind.GetUnaryOperatorPrecedence();
var binaryPrecedence = binaryKind.GetBinaryOperatorPrecedence();
var unaryText = SyntaxFacts.GetText(unaryKind);
var binaryText = SyntaxFacts.GetText(binaryKind);
var text = $"{unaryText} a {binaryText} b";
var expression = SyntaxTree.Parse(text).Root;
if (unaryPrecedence >= binaryPrecedence)
{
// binary
// / \
// unary b
// |
// a
using (var e = new AssertingEnumerator(expression))
{
e.AssertNode(SyntaxKind.BinaryExpression);
e.AssertNode(SyntaxKind.UnaryExpression);
e.AssertToken(unaryKind, unaryText);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.IdentifierToken, "a");
e.AssertToken(binaryKind, binaryText);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.IdentifierToken, "b");
}
}
else
{
// unary
// |
// binary
// / \
// a b
using (var e = new AssertingEnumerator(expression))
{
e.AssertNode(SyntaxKind.UnaryExpression);
e.AssertToken(unaryKind, unaryText);
e.AssertNode(SyntaxKind.BinaryExpression);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.IdentifierToken, "a");
e.AssertToken(binaryKind, binaryText);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.IdentifierToken, "b");
}
}
}
public void Parser_BinaryExpression_HonorsPrecedences(SyntaxKind op1, SyntaxKind op2)
{
var op1Precedence = SyntaxFacts.GetBinaryOperatorPrecedence(op1);
var op2Precedence = SyntaxFacts.GetBinaryOperatorPrecedence(op2);
var op1Text = SyntaxFacts.GetText(op1);
var op2Text = SyntaxFacts.GetText(op2);
var text = $"a {op1Text} b {op2Text} c";
var expression = SyntaxTree.Parse(text).Root;
if (op1Precedence >= op2Precedence)
{
// op2
// / \
// op1 c
// / \
// a b
using (var e = new AssertingEnumerator(expression))
{
e.AssertNode(SyntaxKind.BinaryExpression);
e.AssertNode(SyntaxKind.BinaryExpression);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.IdentifierToken, "a");
e.AssertToken(op1, op1Text);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.IdentifierToken, "b");
e.AssertToken(op2, op2Text);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.IdentifierToken, "c");
}
}
else
{
// op1
// / \
// a op2
// / \
// b c
using (var e = new AssertingEnumerator(expression))
{
e.AssertNode(SyntaxKind.BinaryExpression);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.IdentifierToken, "a");
e.AssertToken(op1, op1Text);
e.AssertNode(SyntaxKind.BinaryExpression);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.IdentifierToken, "b");
e.AssertToken(op2, op2Text);
e.AssertNode(SyntaxKind.NameExpression);
e.AssertToken(SyntaxKind.IdentifierToken, "c");
}
}
}