Implement Derive for ParamType::Tuple

[fordN]

Tuple support has been implemented without derive for now. The derive functions that need Tuple implementations are as follows (click to link to the code):

• to_syntax_string()
• rust_type()
• template_param_type()
• to_token()
• from_token()

[BlinkyStitt]

I just ran into this. Has anyone done any work here? Any suggestions for how to do this? This issue blocks me from using ethabi_derive.

I'd help, but this is my first time really using proc macros and so I'll need to learn a lot before I do anything