Slice-pattern.cpp

#include "matchit.h"
#include <iostream>
#include <vector>
using namespace matchit;

void sample1()
{
  // Fixed size
  constexpr auto arr = std::array<int32_t, 3>{1, 2, 3};
  Id<int32_t> a, b, c;
  match(arr)(pattern | ds(1, _, _) = expr("starts with one"),
             pattern | ds(a, b, c) = expr("starts with something else"));
}

void sample2()
{
  // Dynamic size
  auto const v = std::vector<int32_t>{1, 2, 3};
  Id<int32_t> a, b, c;
  match(v)(
      // format off
      pattern | ds(a, b) =
          [] { /* this arm will not apply because the length doesn't match */ },
      pattern | ds(a, b, c) = [] { /* this arm will apply */ },
      pattern | ds(_) =
          [] { /* this wildcard is required, since the length is not known
                  statically */
          }    // format on
  );
}

int32_t main()
{
  sample1();
  sample2();
  return 0;
}