private static bool NeedsParenthesesInCSharp(this Expression child, Expression parent)
{
if (parent is Eval) parent = ((Eval)parent).Parent as Expression;
if (child == null || parent == null) return false;
var p_app = parent as Apply;
if (p_app != null)
{
if (p_app.Callee == child)
{
return false;
}
else
{
var m = p_app.InvokedMethod();
if (m != null)
{
var reallySpecial = m.IsSpecialName && !m.IsConstructor && m.EnclosingProperty() == null;
var childIsFirstArg = p_app.Args.FirstOrDefault() == child;
var explicitThis = m.IsInstance() || m.IsExtension();
if (!reallySpecial && (!childIsFirstArg || !explicitThis)) return false;
}
else
{
var p = p_app.InvokedProperty();
if (p != null)
{
return false;
}
else
{
(p_app.Callee == null).AssertTrue();
return false;
}
}
}
}
if (child is Apply)
{
var m = child.InvokedMethod();
if (m != null)
{
if (m.IsUserDefinedOperator())
{
// todo. add support for op_UnaryPlus
var op_type = (OperatorType)Enum.Parse(typeof(OperatorType), m.UserDefinedOperatorType());
var equiv = Operator.Create(op_type, ((Apply)child).Args);
return equiv.NeedsParenthesesInCSharp(parent);
}
else if (m.IsUserDefinedCast())
{
(m.Paramc() == 1).AssertTrue();
var targetType = m.Ret();
var source = ((Apply)child).Args.Single();
// todo. think about cases when we can omit the cast
// and, thus, need other algorithm of determining
// whether we need parentheses or not
var equiv = new Convert(targetType, source);
return equiv.NeedsParenthesesInCSharp(parent);
}
}
}
// heuristics: this makes prettyprints more readable
// todo. some day think this over again
// check out examples in Truesight.Playground\Decompiler\Reference
// for more thinking material
if (parent is Operator && child is Operator)
{
var p_op = ((Operator)parent).OperatorType;
var c_op = ((Operator)child).OperatorType;
if (c_op.IsRelational() && p_op.IsEquality()) return true;
if (p_op == c_op) return false;
if (c_op == OperatorType.PostDecrement ||
c_op == OperatorType.PostIncrement ||
c_op == OperatorType.PreDecrement ||
c_op == OperatorType.PreIncrement ||
c_op == OperatorType.Negate ||
c_op == OperatorType.Not)
{
return false;
}
if (p_op == OperatorType.AndAlso ||
p_op == OperatorType.OrElse)
{
return true;
}
}
if (child is Operator)
{
if (child.CSharpPriority() == Operator.PreIncrement().CSharpPriority())
{
return child.CSharpPriority() < parent.CSharpPriority();
}
else
{
return child.CSharpPriority() <= parent.CSharpPriority();
}
}
else if (child is Assign)
{
return child.CSharpPriority() <= parent.CSharpPriority();
}
else if (child is Addr)
{
return child.CSharpPriority() <= parent.CSharpPriority();
}
else if (child is CollectionInit)
{
return false;
}
else if (child is Conditional)
{
return child.CSharpPriority() <= parent.CSharpPriority();
}
else if (child is Const)
{
return false;
}
else if (child is Convert)
{
return child.CSharpPriority() <= parent.CSharpPriority() && !(parent is Convert);
}
else if (child is Deref)
{
return child.CSharpPriority() <= parent.CSharpPriority();
}
else if (child is Slot)
{
return false;
}
else if (child is Loophole)
{
return false;
}
else if (child is ObjectInit)
{
return false;
}
else if (child is Ref)
{
return false;
}
else if (child is SizeOf)
{
return false;
}
else if (child is TypeAs)
{
return child.CSharpPriority() <= parent.CSharpPriority();
}
else if (child is TypeIs)
{
return child.CSharpPriority() <= parent.CSharpPriority();
}
else if (child is Default)
{
return false;
}
else if (child is Apply)
{
return false;
}
else if (child is Eval)
{
return false;
}
else if (child is Lambda)
{
return false;
}
else
{
throw AssertionHelper.Fail();
}
}
