Improve ParamTypeToInterfacePass to only ignore the first param of operators

[ddobrev]

C# requires the first param to match the containing type but the rest can be anything so we'd better map them to their interfaces, if any.

[genuinelucifer]

@ddobrev
Did you mean to ignore the 1st param for Operators and for the rest params do as for other functions?
Something like:

diff --git a/src/Generator/Passes/ParamTypeToInterfacePass.cs b/src/Generator/Pa
index 34f1cea..6717097 100644
--- a/src/Generator/Passes/ParamTypeToInterfacePass.cs
+++ b/src/Generator/Passes/ParamTypeToInterfacePass.cs
@@ -7,13 +7,13 @@ public class ParamTypeToInterfacePass : TranslationUnitPass
     {
         public override bool VisitFunctionDecl(Function function)
         {
-            if (!function.IsOperator)
+            ChangeToInterfaceType(function.ReturnType);
+            bool isFirstParam = true;
+            foreach (Parameter parameter in function.Parameters)
             {
-                ChangeToInterfaceType(function.ReturnType);
-                foreach (Parameter parameter in function.Parameters)
-                {
+                if(!function.IsOperator || !isFirstParam)
                     ChangeToInterfaceType(parameter.QualifiedType);
-                }
+                isFirstParam = false;
             }
             return base.VisitFunctionDecl(function);
         }

[ddobrev]

@genuinelucifer yes, this is exactly what I mean. However, please do not check for the first parameter this way but rather by checking Parameter.Kind for OperatorParameter. In fact, you should be able to remove the check for an operator and simply exclude any operator parameters from the loop:

    public override bool VisitFunctionDecl(Function function)
    {
        ChangeToInterfaceType(function.ReturnType);
        foreach (var parameter in function.Parameters.Where(p => p.Kind != ParameterKind.OperatorParameter))
            ChangeToInterfaceType(parameter.QualifiedType);
        return base.VisitFunctionDecl(function);
    }

[genuinelucifer]

@ddobrev wouldn't it exclude all the parameters (not just the first) for any operator?

[ddobrev]

OperatorParameter is used only for the special first parameter C# requires to be of the containing type.

[genuinelucifer]

@ddobrev So, this is the final solution what you gave! Should i open a pull request only with this? or is there something more to it?

[ddobrev]

@genuinelucifer there's just a test to add to verify my solution actually works, I wrote it in the blind, you know.

[genuinelucifer]

@ddobrev This might seem silly but what does this function actually do? I mean how do i define an interface in C++ and what is @interface for a parameter??

[ddobrev]

I assume you're asking this question just to be clear, not that you need it for the fix itself.
C++ does not have interfaces. It has multiple inheritance. C# doesn't so we have to emulate secondary base classes with C# interfaces.

[genuinelucifer]

Well, partly because of both reasons. I could not find why we have to use
ParamTypeToInterfacePass at all!
Because I thought C++ doesn't have interfaces so how are interfaces coming
into picture!
On 20-Jun-2015 4:44 PM, "Dimitar Dobrev" notifications@github.com wrote:

I assume you're asking this question just to be clear, not that you need
it for the fix itself.
C++ does not have interfaces. It has multiple inheritance. C# doesn't so
we have to emulate secondary base classes with C# interfaces.

—
Reply to this email directly or view it on GitHub
#334 (comment).

[genuinelucifer]

@ddobrev Thanks..
Well, I had to change a few bits here and there and it is working okay.
Except that "ParameterKind.OperatorParameter" is set only for first param of normal operators. For constructors such as:

class DLL_API P : Proprietor
{
public:
    P(const Qux& qux);
    P(Qux* qux);

following is generated:

public static implicit operator P(Qux qux)

and the function is marked with IsOperator but the first parameter is NOT marked with ParameterKind.OperatorParameter...
Should I mark the first param for this declaration with ParameterKind.OperatorParameter or should I check for first parameter in some other way?

[genuinelucifer]

@ddobrev Please see #495.

[tritao]

#495