From CppNow 2013

[bearophile]

Among the CppNow 2013 slide packs I have found two interesting 
things:

https://github.com/boostcon/cppnow_presentations_2013

----------------------

One is from "Concepts Lite: Constraining Templates with 
Predicates" by Andrew Suttoon, Bjarne Stroustrup et al:

https://github.com/boostcon/cppnow_presentations_2013/blob/master/thu/concepts-lite.pdf?raw=true

This is a D version of C++13 code that uses Concepts Lite:

void sort(C)(C cont) if (SortableContainer!C) {}

They suggest to allow a syntax like this, usable when the 
template constraint has only one argument:

void sort(SortableContainer cont) {}

It's handy especially for lambdas:

(Regular x) => x == y;


If you have two or more types, they must be the same (if you 
don't want this, you have to use the normal longer syntax):

void foo(isRandomAccessRange a,
          isRandomAccessRange b) {
     static assert(is(typeof(a) == typeof(b))); // true.
}


The total number of concepts they define is quite small:

Equality_comparable
Totally_ordered
Regular
Function
Predicate
Relation
Input_iterator
Forward_iterator
Bidirectional_iterator
Sortable

----------------------

The other nice thing I've seen is here:

"Dynamic, Recursive, Heterogeneous Types in Statically-Typed 
Languages" by Richard Saunders, Clinton Jeffery:

https://github.com/boostcon/cppnow_presentations_2013/blob/master/fri/DynRec.pdf?raw=true

They define Tab, Val and little else that allows them to offer a 
dynamic data structure as similar as possible to the Python dicts:

# Python
d = {'a':1, 'b':2.2, 'c':[1,2.2,'three']}
v = int(d['c'][0])
v +=3
d['c'][2] = v


The C++ syntax they use:

Tab d="{'a':1,'b':2.2,'c':[1,2.2,'three']}";
int v = d("c")(0);
v += 3;
d["c"][2] = v;


Another example in C++:

Tab t = "{'a':{'nest':1}}";
cout << t["a"]["nest"] << endl;
t["a"]["nest"] = 17;

Bye,
bearophile