diff options
| -rw-r--r-- | spec/util_iterators_spec.lua | 30 | ||||
| -rw-r--r-- | util/iterators.lua | 13 |
2 files changed, 43 insertions, 0 deletions
diff --git a/spec/util_iterators_spec.lua b/spec/util_iterators_spec.lua index d00058f4..c819b2f0 100644 --- a/spec/util_iterators_spec.lua +++ b/spec/util_iterators_spec.lua @@ -11,4 +11,34 @@ describe("util.iterators", function () assert.same(output, expect); end); end); + + describe("sorted_pairs", function () + it("should produce sorted pairs", function () + local orig = { b = 1, c = 2, a = "foo", d = false }; + local n, last_key = 0, nil; + for k, v in iter.sorted_pairs(orig) do + n = n + 1; + if last_key then + assert(k > last_key, "Expected "..k.." > "..last_key) + end + last_key = k; + end + assert.equal("d", last_key); + assert.equal(4, n); + end); + + it("should allow a custom sort function", function () + local orig = { b = 1, c = 2, a = "foo", d = false }; + local n, last_key = 0, nil; + for k, v in iter.sorted_pairs(orig, function (a, b) return a > b end) do + n = n + 1; + if last_key then + assert(k < last_key, "Expected "..k.." > "..last_key) + end + last_key = k; + end + assert.equal("a", last_key); + assert.equal(4, n); + end); + end); end); diff --git a/util/iterators.lua b/util/iterators.lua index 5d16d8c1..302cca36 100644 --- a/util/iterators.lua +++ b/util/iterators.lua @@ -177,6 +177,19 @@ function it.to_array(f, s, var) return t; end +function it.sorted_pairs(t, sort_func) + local keys = it.to_array(it.keys(t)); + table.sort(keys, sort_func); + local i = 0; + return function () + i = i + 1; + local key = keys[i]; + if key ~= nil then + return key, t[key]; + end + end; +end + -- Treat the return of an iterator as key,value pairs, -- and build a table function it.to_table(f, s, var) |