Restructure

7 files changed, 502 insertions, 0 deletions

diff --git a/src/Bool.gleam b/src/Bool.gleam
new file mode 100644
index 0000000..ef39179
--- /dev/null
+++ b/src/Bool.gleam
@@ -0,0 +1,62 @@
+module Bool
+
+export Bool(..), not/1, compare/2, max/2, min/2
+
+import Order exposing Order(_)
+
+type Bool
+  = True
+  | False
+
+fn not(bool) =
+  case bool
+  | True => False
+  | False => True
+
+test not =
+  not(True) |> Assert.false
+  not(False) |> Assert.true
+
+fn compare(a, b) =
+  case (a, b)
+  | (True, True) => EQ
+  | (True, False) => GT
+  | (False, False) => LT
+  | (False, True) => GT
+
+test compare =
+  compare(True, True) |> Assert.equal(_, EQ)
+  compare(True, False) |> Assert.equal(_, GT)
+  compare(False, False) |> Assert.equal(_, LT)
+  compare(False, True) |> Assert.equal(_, GT)
+
+fn max(a, b) =
+  case a
+  | True => True
+  | False => b
+
+test max =
+  max(True, True) |> Assert.equal(_, True)
+  max(True, False) |> Assert.equal(_, True)
+  max(False, False) |> Assert.equal(_, False)
+  max(False, True) |> Assert.equal(_, True)
+
+fn min(a, b) =
+  case a
+  | False => False
+  | True => b
+
+test min =
+  min(True, True) |> Assert.equal(_, True)
+  min(True, False) |> Assert.equal(_, False)
+  min(False, False) |> Assert.equal(_, False)
+  min(False, True) |> Assert.equal(_, False)
+
+fn to_int(bool) =
+  case bool
+  | False => 0
+  | True => 1
+
+test to_int =
+  to_int(True) |> Assert.equal(_, 1)
+  to_int(False) |> Assert.equal(_, 0)
diff --git a/src/Foreign.gleam b/src/Foreign.gleam
new file mode 100644
index 0000000..66cbd9f
--- /dev/null
+++ b/src/Foreign.gleam
@@ -0,0 +1,15 @@
+module Foreign
+
+export Foreign, new/1
+
+doc """
+Foreign data is data that we don't know the type of yet.
+We likely get data like this from interop with Erlang, or from
+IO with the outside world.
+"""
+foreign type Foreign
+
+doc """
+Convert any Gleam data into Foreign data.
+"""
+foreign new :gleam_native :identity :: a -> Foreign
diff --git a/src/List.gleam b/src/List.gleam
new file mode 100644
index 0000000..67b713e
--- /dev/null
+++ b/src/List.gleam
@@ -0,0 +1,166 @@
+module List
+
+export length/1, reverse/1, empty/1, member/2, head/1, tail/1, filter/2,
+       foldl/3, foldr/3, map/2, flatten/1, drop/2, take/2, of/1, new/0
+
+import Maybe exposing Maybe(..)
+
+// Using the Erlang C BIF implementation.
+//
+foreign length :erlang :length :: |List(a)| -> Int
+
+test length =
+  length([]) |> Assert.equal(_, 0)
+  length([1]) |> Assert.equal(_, 1)
+  length([1, 1]) |> Assert.equal(_, 2)
+  length([1, 1, 1]) |> Assert.equal(_, 3)
+
+// Using the Erlang C BIF implementation.
+//
+foreign reverse :erlang :reverse :: |List(a)| -> List(a)
+
+test reverse =
+  length([]) |> Assert.equal(_, [])
+  length([1, 2, 3, 4, 5]) |> Assert.equal(_, [5, 4, 3, 2, 1])
+
+fn is_empty(list) =
+  list == []
+
+test is_empty =
+  is_empty([]) |> Assert.true
+  is_empty([1]) |> Assert.false
+
+fn member(list, elem) =
+  case list
+  | [] => False
+  | elem :: _ => True
+  | _ :: rest => member(rest, elem)
+
+test is_member =
+  is_member([0, 4, 5, 1], 1) |> Assert.true
+  is_member([0, 4, 5, 7], 1) |> Assert.false
+  is_member([], 1) |> Assert.false
+
+fn head(list) =
+  case list
+  | [] => Nothing
+  | elem :: _ => Just(elem)
+
+test head =
+  head([0, 4, 5, 7]) |> Assert.equal(_, Just(0))
+  head([]) |> Assert.equal(_, Nothing)
+
+fn tail(list) =
+  case list
+  | [] => Nothing
+  | _ :: rest => Just(rest)
+
+test tail =
+  tail([0, 4, 5, 7]) |> Assert.equal(_, Just([4, 5, 7]))
+  tail([0]) |> Assert.equal(_, Just([]))
+  tail([]) |> Assert.equal(_, Nothing)
+
+fn filter(list, fun) =
+  filter(list, fun, [])
+
+test filter =
+  filter([], |x| True) |> Assert.equal(_, [])
+  filter([0, 4, 5, 7, 3], |x| True) |> Assert.equal(_, [0, 4, 5, 7, 3])
+  filter([0, 4, 5, 7, 3], |x| x > 4) |> Assert.equal(_, [5, 7])
+  filter([0, 4, 5, 7, 3], |x| x < 4) |> Assert.equal(_, [0, 3])
+
+fn filter(list, fun, acc) =
+  case list
+  | [] => reverse(acc)
+  | x :: xs => (
+      new_acc = case fun(x)
+        | True => x :: acc
+        | False => acc
+      filter(xs, fun, new_acc)
+    )
+
+fn map(list, fun) =
+  map(list, fun, [])
+
+test map =
+  map([], |x| * 2) |> Assert.equal(_, [])
+  map([0, 4, 5, 7, 3], |x| x * 2) |> Assert.equal(_, [0, 8, 10, 14, 6])
+
+fn map(list, fun, acc) =
+  case list
+  | [] => reverse(acc)
+  | x :: xs => map(xs, fun, fun(x) :: acc)
+
+fn drop(list, n) =
+  case n <= 0
+  | True => list
+  | False => (
+      case list
+      | [] => []
+      | _ :: xs => drop(xs, n - 1)
+    )
+
+test drop/2 =
+  drop([], 5) |> Assert.equal(_, [])
+  drop([1, 2, 3, 4, 5, 6, 7, 8], 5) |> Assert.equal(_, [6, 7, 8])
+
+fn take(list, n) =
+  take(list, n, [])
+
+fn take(list, n, acc) =
+  case n <= 0
+  | True => reverse(acc)
+  | False => (
+      case list
+      | [] => reverse(acc)
+      | x :: xs => take(xs, n - 1, x :: acc)
+    )
+
+test take =
+  take([], 5) |> Assert.equal(_, [])
+  take([1, 2, 3, 4, 5, 6, 7, 8], 5) |> Assert.equal(_, [1, 2, 3, 4, 5])
+
+fn of(x) =
+  [x]
+
+test of() =
+  of([]) |> Assert.equal(_, [[]])
+  of(1) |> Assert.equal(_, [1])
+
+fn new() =
+  []
+
+test new() =
+  new() |> Assert.equal(_, [])
+
+fn flatten(lists) =
+  flatten(lists, [])
+
+test flatten() =
+  flatten([]) |> Assert.equal(_, [])
+  flatten([[]]) |> Assert.equal(_, [])
+  flatten([[], [], []]) |> Assert.equal(_, [])
+  flatten([[1, 2], [], [3, 4]]) |> Assert.equal(_, [1, 2, 3, 4])
+
+fn flatten(lists, acc) =
+  case lists
+  | [] => acc
+  | l :: rest => flatten(rest, acc ++ l)
+
+fn foldl(list, acc, fun) =
+  case list
+  | [] => acc
+  | x :: rest => foldl(rest, fun(x, acc), fun)
+
+test foldl() =
+  foldl([1, 2, 3], [], |x, acc| x :: acc)
+    |> Assert.equal(_, [3, 2, 1])
+
+fn foldr(list, acc, fun) =
+  case list
+  | [] => acc
+  | x :: rest => fun(x, foldl(rest, acc, fun))
+
+test foldr() =
+  foldr([1, 2, 3], [], |x, acc| x :: acc)
+    |> Assert.equal(_, [1, 2, 3])
diff --git a/src/Maybe.gleam b/src/Maybe.gleam
new file mode 100644
index 0000000..2805a4d
--- /dev/null
+++ b/src/Maybe.gleam
@@ -0,0 +1,63 @@
+module Maybe
+
+export Maybe(..), is_just/1, is_nothing/1, map/2, flatten/1, flat_map/2,
+       unwrap/2
+
+type Maybe(x)
+  = Just(x)
+  | Nothing
+
+fn is_just(maybe) =
+  case maybe
+  | Just(_) => True
+  | Nothing => False
+
+test is_just() =
+  is_just(Just(1)) |> Assert.true
+  is_just(Nothing) |> Assert.false
+
+fn is_nothing(maybe) =
+  case maybe
+  | Just(_) => False
+  | Nothing => True
+
+test is_nothing() =
+  is_nothing(Just(1)) |> Assert.false
+  is_nothing(Nothing) |> Assert.true
+
+fn map(maybe, fun) =
+  case maybe
+  | Just(x) => fun(x)
+  | Nothing => Nothing
+
+test map() =
+  map(Just(1), |x| x + 1) |> Assert.equal(_, Just(2))
+  map(Nothing, |x| x + 1) |> Assert.equal(Nothing)
+
+fn flatten(maybe) =
+  maybe
+    |> unwrap(_, Nothing)
+
+test flatten() =
+  flatten(Just(Just(1))) |> Assert.equal(Just(1))
+  flatten(Just(Nothing)) |> Assert.equal(Nothing)
+  flatten(Nothing) |> Assert.equal(Nothing)
+
+fn flat_map(maybe, fun) =
+  maybe
+    |> map(_, fun)
+    |> flatten
+
+test flat_map() =
+  flat_map(Nothing, |x| Just(x + 1)) |> Assert.equal(Nothing)
+  flat_map(Just(1), |x| Just(x + 1)) |> Assert.equal(Just(2))
+  flat_map(Just(1), |_| Nothing) |> Assert.equal(Nothing)
+
+fn unwrap(maybe, fallback) =
+  case maybe
+  | Just(v) => v
+  | Nothing => fallback
+
+test unwrap() =
+  unwrap(Just(1), 50) |> Assert.equal(1)
+  unwrap(Nothing, 50) |> Assert.equal(50)
diff --git a/src/Order.gleam b/src/Order.gleam
new file mode 100644
index 0000000..76ed92b
--- /dev/null
+++ b/src/Order.gleam
@@ -0,0 +1,84 @@
+module Order
+
+export Order(..), reverse/1, to_int/1, compare/2, max/2, min/2
+
+type Order
+  = LT
+  | EQ
+  | GT
+
+fn reverse(order) =
+  case order
+  | LT => GT
+  | EQ => EQ
+  | GT => LT
+
+test reverse =
+  reverse(LT) |> Assert.equal(_, GT)
+  reverse(EQ) |> Assert.equal(_, EQ)
+  reverse(GT) |> Assert.equal(_, LT)
+
+fn to_int(order) =
+  case order
+  | LT => -1
+  | EQ => 0
+  | GT => 1
+
+test to_int =
+  to_int(LT) |> Assert.equal(_, -1)
+  to_int(EQ) |> Assert.equal(_, 0)
+  to_int(GT) |> Assert.equal(_, 1)
+
+fn compare(a, b) =
+  case (a, b)
+  | (LT, LT) => EQ
+  | (LT, _) => LT
+  | (EQ, EQ) => EQ
+  | (GT, GT) => EQ
+  | (EQ, GT) => LT
+  | _ => GT
+
+test compare =
+  compare(LT, LT) |> Assert.equal(_, EQ)
+  compare(LT, EQ) |> Assert.equal(_, LT)
+  compare(LT, GT) |> Assert.equal(_, LT)
+  compare(EQ, LT) |> Assert.equal(_, GT)
+  compare(EQ, EQ) |> Assert.equal(_, EQ)
+  compare(EQ, GT) |> Assert.equal(_, LT)
+  compare(GT, LT) |> Assert.equal(_, GT)
+  compare(GT, EQ) |> Assert.equal(_, GT)
+  compare(GT, GT) |> Assert.equal(_, EQ)
+
+fn max(a, b) =
+  case (a, b)
+  | (GT, _) => GT
+  | (EQ, LT) => EQ
+  | _ => b
+
+test max =
+  max(LT, LT) |> Assert.equal(_, LT)
+  max(LT, EQ) |> Assert.equal(_, EQ)
+  max(LT, GT) |> Assert.equal(_, GT)
+  max(EQ, LT) |> Assert.equal(_, EQ)
+  max(EQ, EQ) |> Assert.equal(_, EQ)
+  max(EQ, GT) |> Assert.equal(_, GT)
+  max(GT, LT) |> Assert.equal(_, GT)
+  max(GT, EQ) |> Assert.equal(_, GT)
+  max(GT, GT) |> Assert.equal(_, GT)
+
+fn min(a, b) =
+  case (a, b)
+  | (LT, _) => LT
+  | (EQ, GT) => EQ
+  | _ => b
+
+test min =
+  min(LT, LT) |> Assert.equal(_, LT)
+  min(LT, EQ) |> Assert.equal(_, LT)
+  min(LT, GT) |> Assert.equal(_, LT)
+  min(EQ, LT) |> Assert.equal(_, LT)
+  min(EQ, EQ) |> Assert.equal(_, EQ)
+  min(EQ, GT) |> Assert.equal(_, EQ)
+  min(GT, LT) |> Assert.equal(_, LT)
+  min(GT, EQ) |> Assert.equal(_, EQ)
+  min(GT, GT) |> Assert.equal(_, GT)
diff --git a/src/Result.gleam b/src/Result.gleam
new file mode 100644
index 0000000..ff916e8
--- /dev/null
+++ b/src/Result.gleam
@@ -0,0 +1,97 @@
+module Result
+
+export Result(..), is_ok/1, is_none/1, map/2, map_error/2, flatten/1, flat_map/2,
+       unwrap/2, to_maybe/1, from_maybe/1
+
+import Maybe exposing Maybe(..)
+
+doc """
+Result represents the result of something that may succeed or fail.
+`Ok` means it was successful, `Error` means it failed.
+"""
+type Result(error, value)
+  = Ok(value)
+  | Error(error)
+
+fn is_ok(result) =
+  case result
+  | Error(_) => False
+  | Ok(_) => True
+
+test is_ok =
+  is_ok(Ok(1)) |> Assert.true
+  is_ok(Error(1)) |> Assert.false
+
+fn is_error(result) =
+  case result
+  | Ok(_) => False
+  | Error(_) => True
+
+test is_error =
+  is_error(Ok(1)) |> Assert.false
+  is_error(Error(1)) |> Assert.true
+
+fn map(result, fun) =
+  case result
+  | Ok(x) => fun(x)
+  | Error(_) => result
+
+test map =
+  map(Ok(1), |x| x + 1) |> Assert.equal(_, Ok(2))
+  map(Error(1), |x| x + 1) |> Assert.equal(Error(1))
+
+fn map_error(result, fun) =
+  case result
+  | Ok(_) => result
+  | Error(error) => error |> fun |> Error
+
+test map_error =
+  map_error(Ok(1), |x| x + 1) |> Assert.equal(_, Ok(1))
+  map_error(Error(1), |x| x + 1) |> Assert.equal(Error(2))
+
+fn flatten(result) =
+  case result
+  | Ok(x) => x
+  | Error(_) => result
+
+test flatten =
+  flatten(Ok(Ok(1))) |> Assert.equal(_, Ok(1))
+  flatten(Ok(Error(1))) |> Assert.equal(_, Error(1))
+  flatten(Error(1)) |> Assert.equal(_, Error(1))
+
+fn flat_map(result, fun) =
+  result
+    |> unwrap(_, fun)
+    |> flatten
+
+test flat_map =
+  flat_map(Error(1), |x| Ok(x + 1)) |> Assert.equal(_, Error(1))
+  flat_map(Ok(1), |x| Ok(x + 1)) |> Assert.equal(_, Ok(2))
+  flat_map(Ok(1), |_| Error(1)) |> Assert.equal(_, Error(1))
+
+fn unwrap(result, default) =
+  case result
+  | Ok(v) => v
+  | Error(_) => default
+
+test unwrap =
+  unwrap(Ok(1), 50) |> Assert.equal(_, 1)
+  unwrap(Error("nope"), 50) |> Assert.equal(_, 50)
+
+fn to_maybe(result) =
+  case result
+  | Ok(v) => Just(v)
+  | Error(_) => Nothing
+
+test to_maybe =
+  to_maybe(Ok(1)) |> Assert.equal(_, Just(_, 1))
+  to_maybe(Error(1)) |> Assert.equal(_, Nothing)
+
+fn from_maybe(maybe, error_reason) =
+  case maybe
+  | Just(v) => Ok(v)
+  | Nothing => Error(error_reason)
+
+test from_maybe =
+  to_maybe(Just(1), :ok) |> Assert.equal(_, Ok(1))
+  to_maybe(Nothing, :ok) |> Assert.equal(_, Error(:ok))
diff --git a/src/gleam_stdlib.app.src b/src/gleam_stdlib.app.src
new file mode 100644
index 0000000..a7f5a66
--- /dev/null
+++ b/src/gleam_stdlib.app.src
@@ -0,0 +1,15 @@
+{application, gleam_stdlib,
+ [{description, "An OTP library"},
+  {vsn, "0.1.0"},
+  {registered, []},
+  {applications,
+   [kernel,
+    stdlib
+   ]},
+  {env,[]},
+  {modules, []},
+
+  {maintainers, []},
+  {licenses, ["Apache 2.0"]},
+  {links, []}
+ ]}.