www.digitalmars.com         C & C++   DMDScript  

digitalmars.D - Name resolution in templates issue

I believe this is a flaw in template design, maybe intentional or 
overlooked or possibly my own lack of knowledge.

I have a module with templates in it. I use these templates to 
built up compile time constructs such as methods, properties, and 
fields for various things like classes and interfaces.

One problem I'm having is that when I use non-built in types that 
are in other modules each type can't be found. The 
declaration/definition is correct and I have even fully qualified 
the names.

When I manually import the module with the types then they are 
found. This method can't be used though since the template module 
shouldn't know about any module that uses it. I've tried mixin 
the module using moduleName on the symbols but I get a recursive 
error with moduleName(although I think I can get this to work at 
some point).

The issue is that the symbols are immediately looked up in all 
the modules inside the template module... since they are not 
there, the template fails.
Since the template only builds a string that is eventually mixed 
in as a string, this really shouldn't be a problem. (in fact, I 
know everything about the type which is how I'm able to build the 


I use a template in the templates module to build a string like

      property myType value();

the template fails because myType can be found. If myType was a 
global built in type it would work, except enums.

I've modified the code to create

      property somemodule.myType value();

Which contains the declaration of myType but this too fails. If I 
add an import statement to the template module "import 
somemodule;" then the code works.

But I feel adding the import statement is bad, possibly a 
performance hit? Although the module is almost surely loaded 
before it seems a bit backwards or possibly error prone since the 
template is used to built the module that we are trying to load.

I can also probably wrap the template with a mixin template which 
I think would cause the template to be instantiated in the module 
it is used but feels wrong too(potentially slow the compiler 
Jul 13 2013