[pypy-dev] new branch src-typedunwrap

[Samuele Pedroni]

After discussing with Armin and Holger, I have created a new branch to 
explore typed unwrapping.

This was touched and discussed also in the past, we would like to move 
away from the current generic unwrap to typed versions thereof, also 
because is a reasonable way to express type information about parameters 
that enters functions (for example builtin function implementations) as 
just generic object and then get unwrapped.

As first step we will introduce str_w and int_w space operations, that 
are type specific unwraps for string and integers.

Removing generic unwrapping of lists and tuples (probably up to their 
usage in tests) makes also sense, because in mixed type cases they are 
problematic as RPython operations.

After this we discussed about supplying the gateways with specifier so 
that can also carry out unwrapping and argument type checking int the 
spirit of CPython ParseTuple* operations.

For that we will likely need typed unwrapping for more types and to 
think about the issues of unwrapping vs. going first through the various 
__int__, __str__ conversion special methods.

Samuele.