private ExpressionSyntax Simplify(ExpressionSyntax node)
{
var expression = VisitExpression(node);
try
{
var stringExpression = GetAsString(expression);
var value = CSharpScript.EvaluateAsync(stringExpression).Result;
switch (value)
{
case bool bool_value:
return(expression);
case byte byte_value:
return(SF.LiteralExpression(SK.NumericLiteralExpression, SF.Literal(byte_value)));
case short short_value:
return(SF.LiteralExpression(SK.NumericLiteralExpression, SF.Literal(short_value)));
case int int_value:
return(SF.LiteralExpression(SK.NumericLiteralExpression, SF.Literal(int_value)));
case long long_value:
return(SF.LiteralExpression(SK.NumericLiteralExpression, SF.Literal(long_value)));
default:
throw new NotImplementedException($"Unsupported type: {value.GetType().Name}.");
}
}
catch (Exception)
{
return(expression);
}
}
public static void NotNull(object expression)
{
ExpressionSyntax expr = GetExpression();
CallBinder.StatementSyntax = MakeThrowSyntax(
expr.GetLocation(),
F.BinaryExpression(K.EqualsExpression, expr, F.LiteralExpression(K.NullLiteralExpression)),
"Expected expression to be non-null.", expr.ToString()
);
}
private static StatementSyntax MakeThrowSyntax(Location location, ExpressionSyntax condition, string msg, string expr)
{
// message, expression, file, position, width
string file = location.SourceTree.FilePath;
ArgumentSyntax[] argsSyntax =
{
F.Argument(F.LiteralExpression(K.StringLiteralExpression, F.Literal(msg))),
F.Argument(F.LiteralExpression(K.StringLiteralExpression, F.Literal(expr))),
F.Argument(file == null ? F.LiteralExpression(K.NullLiteralExpression) : F.LiteralExpression(K.StringLiteralExpression, F.Literal(file))),
F.Argument(F.LiteralExpression(K.NumericLiteralExpression, F.Literal(location.SourceSpan.Start))),
F.Argument(F.LiteralExpression(K.NumericLiteralExpression, F.Literal(location.SourceSpan.Length)))
};
return(F.IfStatement(
condition,
F.ParseStatement($"throw new {typeof(AssertionException).FullName}({string.Join<ArgumentSyntax>(", ", argsSyntax)});")
));
}
private ExpressionSyntax VisitExpression(ExpressionSyntax node)
{
if (node is BinaryExpressionSyntax binaryExpresson)
{
var left = Simplify(binaryExpresson.Left);
var right = Simplify(binaryExpresson.Right);
return(SF.BinaryExpression(node.Kind(), left, right));
}
if (node is IdentifierNameSyntax identifierName)
{
var value = Variables[identifierName.Identifier.Text];
return(value);
}
if (node is LiteralExpressionSyntax)
{
return(node);
}
// Consider:
// https://stackoverflow.com/a/3346729/2869093
// https://stackoverflow.com/a/7812241/2869093
if (node is PrefixUnaryExpressionSyntax prefixUnaryExpression)
{
if (prefixUnaryExpression.Operand is IdentifierNameSyntax operantIdentifierName)
{
operantIdentifierName = (IdentifierNameSyntax)prefixUnaryExpression.Operand;
var value = Variables[operantIdentifierName.Identifier.Text];
switch (node.Kind())
{
case SK.PreDecrementExpression:
return(SF.BinaryExpression(SK.SubtractExpression, value, SF.LiteralExpression(SK.NumericLiteralExpression, SF.Literal(1))));
case SK.PreIncrementExpression:
return(SF.BinaryExpression(SK.AddExpression, value, SF.LiteralExpression(SK.NumericLiteralExpression, SF.Literal(1))));
case SK.UnaryMinusExpression:
case SK.UnaryPlusExpression:
return(node);
default:
throw new NotImplementedException($"Unsupported expression type: {prefixUnaryExpression.Operand.GetType().Name} ({operantIdentifierName.Kind().ToString()})");
}
}
if (prefixUnaryExpression.Operand is LiteralExpressionSyntax)
{
return(node);
}
if (prefixUnaryExpression.Operand is ParenthesizedExpressionSyntax operandParenthesizedExpression)
{
return(SF.PrefixUnaryExpression(prefixUnaryExpression.Kind(), Simplify(operandParenthesizedExpression)));
}
throw new NotImplementedException($"Unsupported expression type: {prefixUnaryExpression.Operand.GetType().Name}");
}
if (node is PostfixUnaryExpressionSyntax postfixUnaryExpression)
{
if (postfixUnaryExpression.Operand is IdentifierNameSyntax operandIdentifierName)
{
var value = Variables[operandIdentifierName.Identifier.Text];
switch (node.Kind())
{
case SK.PostDecrementExpression:
return(SF.BinaryExpression(SK.SubtractExpression, value, SF.LiteralExpression(SK.NumericLiteralExpression, SF.Literal(1))));
case SK.PostIncrementExpression:
return(SF.BinaryExpression(SK.AddExpression, value, SF.LiteralExpression(SK.NumericLiteralExpression, SF.Literal(1))));
default:
throw new NotImplementedException($"Unsupported expression type: {postfixUnaryExpression.Operand.GetType().Name} ({operandIdentifierName.Kind().ToString()})");
}
}
if (postfixUnaryExpression.Operand is LiteralExpressionSyntax)
{
return(node);
}
if (postfixUnaryExpression.Operand is ParenthesizedExpressionSyntax operandParenthesizedExpression)
{
return(SF.PostfixUnaryExpression(postfixUnaryExpression.Kind(), Simplify(operandParenthesizedExpression)));
}
throw new NotImplementedException($"Unsupported expression type: {postfixUnaryExpression.Operand.GetType().Name}");
}
if (node is ParenthesizedExpressionSyntax parenthesizedExpression)
{
return(SF.ParenthesizedExpression(Simplify(parenthesizedExpression.Expression)));
}
throw new NotImplementedException($"Unsupported expression type: {node.GetType().Name}");
}