iod::metamap is an immutable zero-cost key value map. All
operations on metamaps are run by the compiler and have a O(1)
runtime cost. This greatly helps to build high performance
applications while keeping the flexibility of maps.
Compile time has also been reduced thanks to a zero-compile-time cost
key retrieve and the heavy use of parameter pack expansion.
Note: This is a work in progress.
Let's first define some symbols. They will be used as map keys.
IOD_SYMBOL(a)
IOD_SYMBOL(b)A map is a set of key value pairs:
// Create a map
auto m = iod::metamap(s::a = 1, s::b = 2);
// Retrieve map values via direct member access.
// Zero cost neither at runtime nor compile time.
assert(m.a == 1);
// Or via operator[].
assert(m[s::a] == 1);Concatenation of two maps. Values of m1 are given the priority in case of dupplicate keys.
auto m3 = iod::cat(m1, m2);Build the map containing keys present in m1 and m2, taking values from m1.
auto m4 = iod::intersection(m1, m2);Build the map containing keys present in m1 but not in m2, taking values from m1.
auto m5 = iod::substract(m1, m2);Map a function on all key value pairs:
iod::map(m1, [] (auto k, auto v) { std::cout << iod::symbol_string(k) << "=" << v << std::endl; });