[Functional] Adds occa::function and occa::array

[dmed256]

Updates the occa::array to be a type-safe wrapper on occa::memory with flexible functional methods.

occa::function

We introduce a preprocessor macro called OCCA_FUNCTION that takes a C++ lambda and returns a typed occa::function!

Example

occa::function<bool(int, int, const int*)> func = (
  OCCA_FUNCTION({}, [](const int entry, const int index, const int *entries) -> bool {
    return false;
  })
);

The occa::function template definition is taken from std::function, where a user can define the return and argument types. It's also callable just like an std::function

func(0, 0, NULL);

occa::array

We introduce a simple wrapper on occa::memory which is typed and contains some of the core map and reduce functional methods.

Example

const double dynamicValue = 10;
const double compileTimeValue = 100;

occa::scope scope({
  // Passed as arguments
    {"dynamicValue", dynamicValue}
  }, {
  // Passed as compile-time #defines
    {"defines/compileTimeValue", compileTimeValue}
});

occa::array<double> doubleValues = (
  values.map(OCCA_FUNCTION(scope, [](int value) -> double {
    return compileTimeValue + (dynamicValue * value);
  }));  
);

Core methods

• map
• mapTo
• forEach
• reduce

Reduction

• max
• min
• every
• some

Re-indexing

• reverse
• shiftLeft
• shiftRight

Slice/Concat

• slice
• concat

Utility

• fill
• cast

Search

• find
• findIndex
• includes
• indexOf
• lastIndexOf

[codecov]

Codecov Report

Merging #442 (47fd96f) into main (483de16) will decrease coverage by 1.01%.
The diff coverage is 78.28%.

@@            Coverage Diff             @@
##             main     #442      +/-   ##
==========================================
- Coverage   76.03%   75.02%   -1.02%     
==========================================
  Files         249      250       +1     
  Lines       18850    19104     +254     
==========================================
  Hits        14333    14333              
- Misses       4517     4771     +254     

Impacted Files	Coverage Δ
include/occa/core/kernelArg.hpp	100.00% <ø> (ø)
include/occa/core/memory.hpp	100.00% <ø> (ø)
include/occa/functional/scope.hpp	0.00% <ø> (ø)
include/occa/types/json.hpp	71.34% <ø> (-1.65%)	⬇️
src/c/scope.cpp	92.85% <ø> (ø)
src/occa/internal/bin/occa.cpp	38.51% <0.00%> (ø)
src/occa/internal/c/types.cpp	80.00% <ø> (ø)
src/occa/internal/lang/file.cpp	93.50% <ø> (ø)
src/occa/internal/lang/modes/cuda.cpp	63.39% <0.00%> (-3.59%)	⬇️
src/functional/function.cpp	50.00% <50.00%> (ø)
... and 66 more