string interpolation for python

[Jussi Piitulainen]

Yingjie Lan writes:

> Clearly dynamic strings are much more powerful,
> allowing arbitrary expressions inside. It is also
> more terse and readable, since we need no dictionary.
...
> On the implementation, I would suppose new 
> syntax is needed (though very small).

I don't think you need any new syntax to implement this.
You can use a syntax like Dynamite("Hello, $world$") now,
similar to fraction.Fraction:

>>> Fraction(3,4) + 1
Fraction(7, 4)

No special syntax there, yet it can be done.