diff options
| -rw-r--r-- | CHANGELOG.md | 1 | ||||
| -rw-r--r-- | gen/src/gleam@pair.erl | 10 | ||||
| -rw-r--r-- | gen/test/gleam@pair_test.erl | 16 | ||||
| -rw-r--r-- | src/gleam/pair.gleam | 10 | ||||
| -rw-r--r-- | test/gleam/pair_test.gleam | 34 |
5 files changed, 69 insertions, 2 deletions
diff --git a/CHANGELOG.md b/CHANGELOG.md index 2ff57af..d31575e 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -2,6 +2,7 @@ ## Unreleased +- The `pair` module gains the `map_first`, and `map_second` functions. - The `string` module gains the `compare` function. ## v0.4.0 - 2019-09-19 diff --git a/gen/src/gleam@pair.erl b/gen/src/gleam@pair.erl index 887adb9..3361dc7 100644 --- a/gen/src/gleam@pair.erl +++ b/gen/src/gleam@pair.erl @@ -1,7 +1,7 @@ -module(gleam@pair). -compile(no_auto_import). --export([first/1, second/1, swap/1]). +-export([first/1, second/1, swap/1, map_first/2, map_second/2]). first(Tup) -> {A, _} = Tup, @@ -14,3 +14,11 @@ second(Tup) -> swap(Tup) -> {A, B} = Tup, {B, A}. + +map_first(Tup, F) -> + {A, B} = Tup, + {F(A), B}. + +map_second(Tup, F) -> + {A, B} = Tup, + {A, F(B)}. diff --git a/gen/test/gleam@pair_test.erl b/gen/test/gleam@pair_test.erl index 775f161..6a2c856 100644 --- a/gen/test/gleam@pair_test.erl +++ b/gen/test/gleam@pair_test.erl @@ -1,7 +1,7 @@ -module(gleam@pair_test). -compile(no_auto_import). --export([first_test/0, second_test/0, swap_test/0]). +-export([first_test/0, second_test/0, swap_test/0, map_first_test/0, map_second_test/0]). first_test() -> gleam@expect:equal(gleam@pair:first({1, 2}), 1), @@ -13,3 +13,17 @@ second_test() -> swap_test() -> gleam@expect:equal(gleam@pair:swap({1, <<"2">>}), {<<"2">>, 1}). + +map_first_test() -> + Inc = fun(A) -> A + 1 end, + gleam@expect:equal(gleam@pair:map_first({1, 2}, Inc), {2, 2}), + gleam@expect:equal(gleam@pair:map_first({8, 2}, Inc), {9, 2}), + gleam@expect:equal(gleam@pair:map_first({0, -2}, Inc), {1, -2}), + gleam@expect:equal(gleam@pair:map_first({-10, 20}, Inc), {-9, 20}). + +map_second_test() -> + Dec = fun(A) -> A - 1 end, + gleam@expect:equal(gleam@pair:map_second({1, 2}, Dec), {1, 1}), + gleam@expect:equal(gleam@pair:map_second({8, 2}, Dec), {8, 1}), + gleam@expect:equal(gleam@pair:map_second({0, -2}, Dec), {0, -3}), + gleam@expect:equal(gleam@pair:map_second({-10, 20}, Dec), {-10, 19}). diff --git a/src/gleam/pair.gleam b/src/gleam/pair.gleam index 9074330..32fc6d1 100644 --- a/src/gleam/pair.gleam +++ b/src/gleam/pair.gleam @@ -17,3 +17,13 @@ pub fn swap(tup) { let Pair(a, b) = tup Pair(b, a) } + +pub fn map_first(tup, f) { + let Pair(a, b) = tup + Pair(f(a), b) +} + +pub fn map_second(tup, f) { + let Pair(a, b) = tup + Pair(a, f(b)) +} diff --git a/test/gleam/pair_test.gleam b/test/gleam/pair_test.gleam index 54a12af..5dd2690 100644 --- a/test/gleam/pair_test.gleam +++ b/test/gleam/pair_test.gleam @@ -26,3 +26,37 @@ pub fn swap_test() { |> pair.swap |> expect.equal(_, pair.Pair("2", 1)) } + +pub fn map_first_test() { + let inc = fn(a) { + a + 1 + } + pair.map_first(pair.Pair(1, 2), inc) + |> expect.equal(_, pair.Pair(2, 2)) + + pair.map_first(pair.Pair(8,2), inc) + |> expect.equal(_, pair.Pair(9, 2)) + + pair.map_first(pair.Pair(0,-2), inc) + |> expect.equal(_, pair.Pair(1, -2)) + + pair.map_first(pair.Pair(-10, 20), inc) + |> expect.equal(_, pair.Pair(-9, 20)) +} + +pub fn map_second_test() { + let dec = fn(a) { + a - 1 + } + pair.map_second(pair.Pair(1, 2), dec) + |> expect.equal(_, pair.Pair(1, 1)) + + pair.map_second(pair.Pair(8,2), dec) + |> expect.equal(_, pair.Pair(8, 1)) + + pair.map_second(pair.Pair(0,-2), dec) + |> expect.equal(_, pair.Pair(0, -3)) + + pair.map_second(pair.Pair(-10, 20), dec) + |> expect.equal(_, pair.Pair(-10, 19)) +} |