Need DMD AST expertise

[Guillaume Chatelet via Digitalmars-d]

On Tuesday, 21 June 2016 at 19:42:54 UTC, Elie Morisse wrote:
> On Monday, 20 June 2016 at 20:52:02 UTC, Guillaume Chatelet 
> wrote:
>> [...]
>
> The templated function is the child symbol of the 
> TemplateDeclaration which shares the same name i.e
>
> [...]

Thx Elie! It helps :)

I came up with this quick and dirty piece of code to get the 
parameters from the template declaration and the function 
declaration:

code:
> auto declaration = 
> cast(TemplateDeclaration)templateInstance.tempdecl;
> assert(declaration);
> printf("TemplateDeclaration %x\n", declaration);
> foreach(parameter; *declaration.parameters) {
>     printf("Parameter %s\n", parameter.ident.toChars());
> }
> 
> if (declaration.onemember) {
>     FuncDeclaration fd = 
> declaration.onemember.isFuncDeclaration();
>     if (fd && fd.type) {
>         TypeFunction tf = cast(TypeFunction)fd.type;
>         assert(tf);
>         printf("TypeFunction %x\n", tf);
>         if(tf.next) printf("Parameter return %s\n", 
> tf.next.toChars());
>         if(tf.parameters) foreach(parameter; *tf.parameters) {
>             printf("Parameter %s\n", parameter.type.toChars());
>         }
>     }
> }

input:
> extern(C++) C foo(A, B, C)(B, A);

output:
> TemplateDeclaration 764f76b0
> Parameter A
> Parameter B
> Parameter C
> TypeFunction 764f7370
> Parameter return C
> Parameter B
> Parameter A

It works as expected. I still need to do the mapping and handle 
subtleties like this but I'm on the right track.
> extern(C++) ref C foo(A, B, C)(B*, const(A)*);

Thx!