Fix missing implementation and add missing conversion function in Duration.

.github/workflows/ci.yml

@@ -0,0 +1,68 @@
+name: CI
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+
+  build-and-test:
+    strategy:
+      fail-fast: true
+      matrix:
+        os:
+          - ubuntu-latest
+          - macos-latest
+        ocaml-compiler:
+          - 5
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout Tree
+        uses: actions/checkout@v4
+
+      - name: Set-up OCaml
+        uses: ocaml/setup-ocaml@v3
+        with:
+          ocaml-compiler: ${{ matrix.ocaml-compiler }}
+
+      - run: opam install . --deps-only --with-test
+      - run: opam exec -- dune build
+      - run: opam exec -- dune runtest
+
+  lint-doc:
+    strategy:
+      fail-fast: true
+      matrix:
+        os: [ ubuntu-latest ]
+        ocaml-compiler: [ ocaml-base-compiler.5.4.0 ]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout Tree
+        uses: actions/checkout@v4
+
+      - name: Set-up OCaml
+        uses: ocaml/setup-ocaml@v3
+        with:
+          ocaml-compiler: ${{ matrix.ocaml-compiler }}
+      - uses: ocaml/setup-ocaml/lint-doc@v3
+
+  lint-fmt:
+    strategy:
+      fail-fast: true
+      matrix:
+        os: [ ubuntu-latest ]
+        ocaml-compiler: [ ocaml-base-compiler.5.4.0 ]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - name: Checkout Tree
+        uses: actions/checkout@v4
+
+      - name: Set-up OCaml
+        uses: ocaml/setup-ocaml@v3
+        with:
+          ocaml-compiler: ${{ matrix.ocaml-compiler }}
+      - uses: ocaml/setup-ocaml/lint-fmt@v3

CHANGES.md

@@ -1,3 +1,8 @@
+### unreleased
+
+- Add `Duration.to_(seconds|minutes|hours)` ([gr-im](https://github.com/gr-im))
+- Add an implementation for `Lunar` ([gr-im](https://github.com/gr-im))
+
 ### v1.0.0
 
 - First release of `lunar` exposing _among other things_ `Time`, `Date`, `Datetime`, `Timezone`, `Zoned_datetime` and `Range` (by [xvw](https://github.com/xvw), [gr-im](https://github.com/gr-im)).

lib/dune

@@ -1,7 +1,7 @@
 (library
  (name lunar)
  (public_name lunar)
- (modules_without_implementation sigs lunar)
+ (modules_without_implementation sigs)
  (private_modules util))
 
 (mdx

lib/duration.ml

@@ -13,15 +13,11 @@ let from_minutes x = x |> from_seconds |> Int64.mul 60L
 let from_hours x = x |> from_seconds |> Int64.mul 3600L
 let from_days x = x |> from_seconds |> Int64.mul 86400L
 let one_day = from_days 1
+let one_minute = from_minutes 1
+let one_hour = from_hours 1
 let abs = Int64.abs
 let neg x = Int64.(sub zero x)
 
-let to_days t =
-  if t >= 0L
-  then Int64.(to_int (div t one_day))
-  else Int64.(to_int (div (sub t (sub one_day 1L)) one_day))
-;;
-
 let div_floor a b =
   let q = a / b
   and r = a mod b in
@@ -102,9 +98,9 @@ let pred = Int64.pred
 
 let wdhms x =
   let weeks, rem = Util.i64_div_mod_floor x (from_days 7) in
-  let days, rem = Util.i64_div_mod_floor rem (from_days 1) in
-  let hour, rem = Util.i64_div_mod_floor rem (from_hours 1) in
-  let min, sec = Util.i64_div_mod_floor rem (from_minutes 1) in
+  let days, rem = Util.i64_div_mod_floor rem one_day in
+  let hour, rem = Util.i64_div_mod_floor rem one_hour in
+  let min, sec = Util.i64_div_mod_floor rem one_minute in
   (* MAYBE: an opportunity for labelled-tuple. *)
   ( Int64.to_int weeks
   , Int64.to_int days
@@ -114,16 +110,16 @@ let wdhms x =
 ;;
 
 let dhms x =
-  let days, rem = Util.i64_div_mod_floor x (from_days 1) in
-  let hour, rem = Util.i64_div_mod_floor rem (from_hours 1) in
-  let min, sec = Util.i64_div_mod_floor rem (from_minutes 1) in
+  let days, rem = Util.i64_div_mod_floor x one_day in
+  let hour, rem = Util.i64_div_mod_floor rem one_hour in
+  let min, sec = Util.i64_div_mod_floor rem one_minute in
   (* MAYBE: an opportunity for labelled-tuple. *)
   Int64.to_int days, Int64.to_int hour, Int64.to_int min, Int64.to_int sec
 ;;
 
 let hms x =
-  let hours, rem = Util.i64_div_mod_floor x (from_hours 1) in
-  let min, sec = Util.i64_div_mod_floor rem (from_minutes 1) in
+  let hours, rem = Util.i64_div_mod_floor x one_hour in
+  let min, sec = Util.i64_div_mod_floor rem one_minute in
   (* MAYBE: an opportunity for labelled-tuple. *)
   Int64.to_int hours, Int64.to_int min, Int64.to_int sec
 ;;
@@ -135,6 +131,11 @@ let weekday x =
   weekdays.((id + 7) mod 7)
 ;;
 
+let to_seconds t = t |> to_int64 |> Int64.to_int
+let to_minutes t = Int64.(to_int (div t one_minute))
+let to_hours t = Int64.(to_int (div t one_hour))
+let to_days t = Int64.(to_int (div t one_day))
+
 module CE = struct
   type nonrec t = t
 

lib/duration.mli

@@ -66,7 +66,8 @@ val from_datetime
     [year * month * day_of_month * hour * minute * second]. *)
 val to_datetime : t -> int * int * int * int * int * int
 
-(** [to_int64 d] returns the int64 representation of a duration.*)
+(** [to_int64 d] returns the int64 representation of a duration in
+    seconds. *)
 val to_int64 : t -> int64
 
 (** [wdhms duration] returns the number of weeks, days, hours, minutes, and
@@ -81,7 +82,18 @@ val dhms : t -> int * int * int * int
     seconds that describe the duration.*)
 val hms : t -> int * int * int
 
-(** [to_days duration] get a day approx for a duration. *)
+(** [to_seconds duration] get a seconds approx for a duration. *)
+val to_seconds : t -> int
+
+(** [to_minutes duration] get a minute approx for a duration (drop seconds). *)
+val to_minutes : t -> int
+
+(** [to_hours duration] get a hour approx for a duration (drop seconds,
+    minutes). *)
+val to_hours : t -> int
+
+(** [to_days duration] get a day approx for a duration (drop seconds,
+    minutes and hours). *)
 val to_days : t -> int
 
 (** [weekday d] returns the {!type:Weekday.t} for the given duration since

lib/lunar.ml

@@ -0,0 +1,17 @@
+(* Copyright (c) 2026, Cargocut and the Lunar developers.
+   All rights reserved.
+
+   SPDX-License-Identifier: BSD-3-Clause *)
+
+module Era = Era
+module Month = Month
+module Weekday = Weekday
+module Time = Time
+module Date = Date
+module Datetime = Datetime
+module Timezone = Timezone
+module Zoned_datetime = Zoned_datetime
+module Resolution = Resolution
+module Duration = Duration
+module Range = Range
+module Sigs = Sigs

test/dune

@@ -5,6 +5,7 @@
  (libraries lunar)
  (private_modules
   duration_test
+  duration_conv_test
   month_test
   duration_dhms_test
   duration_weekday_test

test/duration_conv_test.ml

@@ -0,0 +1,180 @@
+(* Copyright (c) 2026, Cargocut and the Lunar developers.
+   All rights reserved.
+
+   SPDX-License-Identifier: BSD-3-Clause *)
+
+let%expect_test "to_seconds" =
+  124 |> Duration.from_seconds |> Duration.to_seconds |> print_int;
+  [%expect {| 124 |}]
+;;
+
+let%expect_test "to_seconds" =
+  -124 |> Duration.from_seconds |> Duration.to_seconds |> print_int;
+  [%expect {| -124 |}]
+;;
+
+let%expect_test "to_minutes" =
+  124 |> Duration.from_minutes |> Duration.to_minutes |> print_int;
+  [%expect {| 124 |}]
+;;
+
+let%expect_test "to_minutes" =
+  -124 |> Duration.from_minutes |> Duration.to_minutes |> print_int;
+  [%expect {| -124 |}]
+;;
+
+let%expect_test "to_hours" =
+  124 |> Duration.from_hours |> Duration.to_hours |> print_int;
+  [%expect {| 124 |}]
+;;
+
+let%expect_test "to_hours" =
+  -124 |> Duration.from_hours |> Duration.to_hours |> print_int;
+  [%expect {| -124 |}]
+;;
+
+let%expect_test "to_days" =
+  124 |> Duration.from_days |> Duration.to_days |> print_int;
+  [%expect {| 124 |}]
+;;
+
+let%expect_test "to_days" =
+  -124 |> Duration.from_days |> Duration.to_days |> print_int;
+  [%expect {| -124 |}]
+;;
+
+let%expect_test "seconds_to_minutes_to_seconds" =
+  360
+  |> Duration.from_seconds
+  |> Duration.to_minutes
+  |> Duration.from_minutes
+  |> Duration.to_seconds
+  |> print_int;
+  [%expect {| 360 |}]
+;;
+
+let%expect_test "negative_seconds_to_minutes_to_seconds" =
+  -360
+  |> Duration.from_seconds
+  |> Duration.to_minutes
+  |> Duration.from_minutes
+  |> Duration.to_seconds
+  |> print_int;
+  [%expect {| -360 |}]
+;;
+
+let%expect_test "minutes_to_hours_to_minutes" =
+  180
+  |> Duration.from_minutes
+  |> Duration.to_hours
+  |> Duration.from_hours
+  |> Duration.to_minutes
+  |> print_int;
+  [%expect {| 180 |}]
+;;
+
+let%expect_test "negative_minutes_to_hours_to_minutes" =
+  -180
+  |> Duration.from_minutes
+  |> Duration.to_hours
+  |> Duration.from_hours
+  |> Duration.to_minutes
+  |> print_int;
+  [%expect {| -180 |}]
+;;
+
+let%expect_test "hours_to_days_to_hours" =
+  48
+  |> Duration.from_hours
+  |> Duration.to_days
+  |> Duration.from_days
+  |> Duration.to_hours
+  |> print_int;
+  [%expect {| 48 |}]
+;;
+
+let%expect_test "negative_hours_to_days_to_hours" =
+  -48
+  |> Duration.from_hours
+  |> Duration.to_days
+  |> Duration.from_days
+  |> Duration.to_hours
+  |> print_int;
+  [%expect {| -48 |}]
+;;
+
+let%expect_test "seconds_to_minutes_to_hours_to_seconds" =
+  7200
+  |> Duration.from_seconds
+  |> Duration.to_minutes
+  |> Duration.from_minutes
+  |> Duration.to_hours
+  |> Duration.from_hours
+  |> Duration.to_seconds
+  |> print_int;
+  [%expect {| 7200 |}]
+;;
+
+let%expect_test "negative_seconds_to_minutes_to_hours_to_seconds" =
+  -7200
+  |> Duration.from_seconds
+  |> Duration.to_minutes
+  |> Duration.from_minutes
+  |> Duration.to_hours
+  |> Duration.from_hours
+  |> Duration.to_seconds
+  |> print_int;
+  [%expect {| -7200 |}]
+;;
+
+let%expect_test "days_to_hours_to_minutes_to_seconds_to_days" =
+  3
+  |> Duration.from_days
+  |> Duration.to_hours
+  |> Duration.from_hours
+  |> Duration.to_minutes
+  |> Duration.from_minutes
+  |> Duration.to_seconds
+  |> Duration.from_seconds
+  |> Duration.to_days
+  |> print_int;
+  [%expect {| 3 |}]
+;;
+
+let%expect_test "negative_days_to_hours_to_minutes_to_seconds_to_days" =
+  -3
+  |> Duration.from_days
+  |> Duration.to_hours
+  |> Duration.from_hours
+  |> Duration.to_minutes
+  |> Duration.from_minutes
+  |> Duration.to_seconds
+  |> Duration.from_seconds
+  |> Duration.to_days
+  |> print_int;
+  [%expect {| -3 |}]
+;;
+
+let%expect_test "non_round_seconds_to_minutes_to_seconds" =
+  90
+  |> Duration.from_seconds
+  |> Duration.to_minutes
+  |> Duration.from_minutes
+  |> Duration.to_seconds
+  |> print_int;
+  [%expect {| 60 |}]
+;;
+
+let%expect_test "large_seconds_conversion" =
+  1_000_000
+  |> Duration.from_seconds
+  |> Duration.to_days
+  |> Duration.from_days
+  |> Duration.to_hours
+  |> Duration.from_hours
+  |> Duration.to_minutes
+  |> Duration.from_minutes
+  |> Duration.to_seconds
+  |> print_int;
+  [%expect {| 950400 |}]
+;;