string module, iodata additions

3 files changed, 173 insertions, 4 deletions

diff --git a/src/gleam__stdlib.erl b/src/gleam__stdlib.erl
index 3ab9fd6..8e288c0 100644
--- a/src/gleam__stdlib.erl
+++ b/src/gleam__stdlib.erl
@@ -8,8 +8,8 @@
          decode_string/1, decode_bool/1, decode_float/1, decode_thunk/1,
          decode_tuple/1, decode_list/1, decode_field/2]).
 
-expect_equal(A, Expected) -> ?assertEqual(Expected, A).
-expect_not_equal(A, Expected) -> ?assertNotEqual(Expected, A).
+expect_equal(Actual, Expected) -> ?assertEqual(Expected, Actual).
+expect_not_equal(Actual, Expected) -> ?assertNotEqual(Expected, Actual).
 expect_true(A) -> ?assert(A).
 expect_false(A) -> ?assertNot(A).
 expect_is_ok(A) -> ?assertMatch({ok, _}, A).
diff --git a/src/iodata.gleam b/src/iodata.gleam
index 2d14ed0..cc54965 100644
--- a/src/iodata.gleam
+++ b/src/iodata.gleam
@@ -8,7 +8,10 @@ pub external fn prepend(Iodata, String) -> Iodata =
 pub external fn append(Iodata, String) -> Iodata =
   "gleam__stdlib" "iodata_append";
 
-pub external fn from(List(String)) -> Iodata =
+pub external fn concat(List(String)) -> Iodata =
+  "gleam__stdlib" "identity";
+
+pub external fn new(String) -> Iodata =
   "gleam__stdlib" "identity";
 
 pub external fn to_string(Iodata) -> String =
@@ -18,7 +21,7 @@ pub external fn byte_size(Iodata) -> Int =
   "erlang" "iolist_size";
 
 test iodata {
-  let iodata = from(["ello"])
+  let iodata = new("ello")
     |> append(_, ",")
     |> append(_, " world!")
     |> prepend(_, "H")
@@ -31,3 +34,90 @@ test iodata {
   |> byte_size
   |> expect:equal(_, 13)
 }
+
+pub external fn lowercase(Iodata) -> Iodata = "string" "lowercase"
+
+test lowercase {
+  ["Gleam", "Gleam"]
+  |> concat
+  |> lowercase
+  |> to_string
+  |> expect:equal(_, "gleamgleam")
+}
+
+pub external fn uppercase(Iodata) -> Iodata = "string" "uppercase"
+
+test uppercase {
+  ["Gleam", "Gleam"]
+  |> concat
+  |> uppercase
+  |> to_string
+  |> expect:equal(_, "GLEAMGLEAM")
+}
+
+pub external fn reverse(Iodata) -> Iodata = "string" "reverse"
+
+enum Direction =
+  | All
+
+external fn erl_split(Iodata, String, Direction) -> List(Iodata) =
+  "string" "split"
+
+pub fn split(iodata, on) {
+  erl_split(iodata, on, All)
+}
+
+test split {
+  "Gleam,Erlang,Elixir"
+  |> new
+  |> split(_, ",")
+  |> expect:equal(_, [new("Gleam"), new("Erlang"), new("Elixir")])
+
+  ["Gleam, Erl", "ang,Elixir"]
+  |> concat
+  |> split(_, ", ")
+  |> expect:equal(_, [new("Gleam"), concat(["Erl", "ang,Elixir"])])
+}
+
+external fn erl_replace(Iodata, String, String, Direction) -> Iodata =
+  "string" "replace"
+
+pub fn replace(iodata, pattern, replacement) {
+  erl_replace(iodata, pattern, replacement, All)
+}
+
+pub external fn is_equal(Iodata, Iodata) -> Bool = "string" "equal"
+
+test is_equal {
+  new("12")
+  |> is_equal(_, concat(["1", "2"]))
+  |> expect:true
+
+  new("12")
+  |> is_equal(_, new("12"))
+  |> expect:true
+
+  new("12")
+  |> is_equal(_, new("2"))
+  |> expect:false
+}
+
+pub external fn is_empty(Iodata) -> Bool = "string" "is_empty"
+
+test is_empty {
+  new("")
+  |> is_empty
+  |> expect:true
+
+  new("12")
+  |> is_empty
+  |> expect:false
+
+  concat([])
+  |> is_empty
+  |> expect:true
+
+  concat(["", ""])
+  |> is_empty
+  |> expect:true
+}
diff --git a/src/str.gleam b/src/str.gleam
new file mode 100644
index 0000000..8aa3e29
--- /dev/null
+++ b/src/str.gleam
@@ -0,0 +1,79 @@
+// Named str to avoid name collisions with the Erlang string module.
+// Will rename later once we have namespaces for modules.
+
+import expect
+import iodata
+import list
+
+pub external fn length(String) -> Int = "string" "length"
+
+test length {
+  length("ß↑e̊")
+  |> expect:equal(_, 3)
+
+  length("Gleam")
+  |> expect:equal(_, 5)
+
+  length("")
+  |> expect:equal(_, 0)
+
+  // TODO: This crashes.
+  // length("é")
+  // |> expect:equal(_, 1)
+}
+
+pub external fn lowercase(String) -> String = "string" "lowercase"
+
+test lowercase {
+  lowercase("Gleam")
+  |> expect:equal(_, "gleam")
+}
+
+pub external fn uppercase(String) -> String = "string" "uppercase"
+
+test uppercase {
+  uppercase("Gleam")
+  |> expect:equal(_, "GLEAM")
+}
+
+pub fn reverse(string) {
+  string
+  |> iodata:new
+  |> iodata:reverse
+  |> iodata:to_string
+}
+
+test reverse {
+  reverse("Gleam")
+  |> expect:equal(_, "maelG")
+}
+
+pub fn split(string, on) {
+  string
+  |> iodata:new
+  |> iodata:split(_, on)
+  |> list:map(_, iodata:to_string)
+}
+
+test split {
+  "Gleam,Erlang,Elixir"
+  |> split(_, ",")
+  |> expect:equal(_, ["Gleam", "Erlang", "Elixir"])
+
+  "Gleam, Erlang,Elixir"
+  |> split(_, ", ")
+  |> expect:equal(_, ["Gleam", "Erlang,Elixir"])
+}
+
+pub fn replace(string, pattern, with) {
+  string
+  |> iodata:new
+  |> iodata:replace(_, pattern, with)
+  |> iodata:to_string
+}
+
+test replace {
+  "Gleam,Erlang,Elixir"
+  |> replace(_, ",", "++")
+  |> expect:equal(_, "Gleam++Erlang++Elixir")
+}