float:round

Author: lpil

CHANGELOG.md

@@ -9,7 +9,8 @@
 - `str` module gains `append` function and loses `from_int`, `parse_int`,
   `from_float`, `parse_float`, and `base_from_int`.
 - `int` module created with `parse`, `to_string`, and `to_base_string`.
-- `float` module created with `ceiling`, `floor`, `parse`, and `to_string`.
+- `float` module created with `ceiling`, `floor`, `round`, `parse`, and
+  `to_string`.
 
 ## v0.1.1 - 2019-04-17
 

gen/src/float.erl

@@ -1,7 +1,7 @@
 -module(float).
 -compile(no_auto_import).
 
--export([parse/1, to_string/1, ceiling/1, floor/1]).
+-export([parse/1, to_string/1, ceiling/1, floor/1, round/1]).
 
 parse(A) ->
     gleam__stdlib:parse_float(A).
@@ -14,3 +14,6 @@ ceiling(A) ->
 
 floor(A) ->
     math:floor(A).
+
+round(A) ->
+    erlang:round(A).

gen/test/float_test.erl

@@ -1,7 +1,7 @@
 -module(float_test).
 -compile(no_auto_import).
 
--export([parse_test/0, to_string_test/0, ceiling_test/0, floor_test/0]).
+-export([parse_test/0, to_string_test/0, ceiling_test/0, floor_test/0, round_test/0]).
 
 parse_test() ->
     expect:equal(float:parse(<<"1.23">>), {ok, 1.23}),
@@ -24,3 +24,11 @@ floor_test() ->
     expect:equal(float:floor(8.1), 8.0),
     expect:equal(float:floor(-8.1), -9.0),
     expect:equal(float:floor(-8.0), -8.0).
+
+round_test() ->
+    expect:equal(float:round(8.1), 8),
+    expect:equal(float:round(8.4), 8),
+    expect:equal(float:round(8.499), 8),
+    expect:equal(float:round(8.5), 9),
+    expect:equal(float:round(-8.1), -8),
+    expect:equal(float:round(-7.5), -8).

src/float.gleam

@@ -15,3 +15,5 @@ pub fn to_string(f) {
 pub external fn ceiling(Float) -> Float = "math" "ceil";
 
 pub external fn floor(Float) -> Float = "math" "floor";
+
+pub external fn round(Float) -> Int = "erlang" "round";

test/float_test.gleam

@@ -64,3 +64,29 @@ pub fn floor_test() {
   |> float:floor
   |> expect:equal(_, -8.0)
 }
+
+pub fn round_test() {
+  8.1
+  |> float:round
+  |> expect:equal(_, 8)
+
+  8.4
+  |> float:round
+  |> expect:equal(_, 8)
+
+  8.499
+  |> float:round
+  |> expect:equal(_, 8)
+
+  8.5
+  |> float:round
+  |> expect:equal(_, 9)
+
+  -8.1
+  |> float:round
+  |> expect:equal(_, -8)
+
+  -7.5
+  |> float:round
+  |> expect:equal(_, -8)
+}