Add Elixir List.Chars protocol.

https://github.com/elixir-lang/elixir/blob/v1.17.2/lib/elixir/lib/list/chars.ex

Split into several source files because of how our CMakeLists.txt is built

Signed-off-by: Paul Guyot <pguyot@kallisys.net>

Author: pguyot

CHANGELOG.md

@@ -22,6 +22,7 @@ also non string parameters (e.g. `Enum.join([1, 2], ",")`
 - Support for `lists:last/1` and `lists:mapfoldl/3`
 - Add support to Elixir for `Process.send/2` `Process.send_after/3/4` and `Process.cancel_timer/1`
 - Add support for `handle_continue` callback in `gen_server`
+- Support for Elixir `List.Chars` protocol
 
 ### Changed
 

libs/exavmlib/lib/CMakeLists.txt

@@ -75,6 +75,13 @@ set(ELIXIR_MODULES
     Collectable.Map
     Collectable.MapSet
 
+    List.Chars
+    List.Chars.Atom
+    List.Chars.BitString
+    List.Chars.Float
+    List.Chars.Integer
+    List.Chars.List
+
     String.Chars
     String.Chars.Atom
     String.Chars.BitString

libs/exavmlib/lib/List.Chars.Atom.ex

@@ -0,0 +1,26 @@
+#
+# This file is part of elixir-lang.
+#
+# Copyright 2013-2023 Elixir Contributors
+# https://github.com/elixir-lang/elixir/commits/v1.17.2/lib/elixir/lib/list/chars.ex
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+defimpl List.Chars, for: Atom do
+  def to_charlist(nil), do: ~c""
+
+  def to_charlist(atom), do: Atom.to_charlist(atom)
+end

libs/exavmlib/lib/List.Chars.BitString.ex

@@ -0,0 +1,36 @@
+#
+# This file is part of elixir-lang.
+#
+# Copyright 2013-2023 Elixir Contributors
+# https://github.com/elixir-lang/elixir/commits/v1.17.2/lib/elixir/lib/list/chars.ex
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+defimpl List.Chars, for: BitString do
+  @doc """
+  Returns the given binary `term` converted to a charlist.
+  """
+  def to_charlist(term) when is_binary(term) do
+    String.to_charlist(term)
+  end
+
+  def to_charlist(term) do
+    raise Protocol.UndefinedError,
+      protocol: @protocol,
+      value: term,
+      description: "cannot convert a bitstring to a charlist"
+  end
+end

libs/exavmlib/lib/List.Chars.Float.ex

@@ -0,0 +1,27 @@
+#
+# This file is part of elixir-lang.
+#
+# Copyright 2013-2023 Elixir Contributors
+# https://github.com/elixir-lang/elixir/commits/v1.17.2/lib/elixir/lib/list/chars.ex
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+defimpl List.Chars, for: Float do
+  def to_charlist(term) do
+    # TODO: :short option not yet supported right now, so :decimals+:compact should be replaced
+    :erlang.float_to_list(term, [{:decimals, 17}, :compact])
+  end
+end

libs/exavmlib/lib/List.Chars.Integer.ex

@@ -0,0 +1,26 @@
+#
+# This file is part of elixir-lang.
+#
+# Copyright 2013-2023 Elixir Contributors
+# https://github.com/elixir-lang/elixir/commits/v1.17.2/lib/elixir/lib/list/chars.ex
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+defimpl List.Chars, for: Integer do
+  def to_charlist(term) do
+    Integer.to_charlist(term)
+  end
+end

libs/exavmlib/lib/List.Chars.List.ex

@@ -0,0 +1,25 @@
+#
+# This file is part of elixir-lang.
+#
+# Copyright 2013-2023 Elixir Contributors
+# https://github.com/elixir-lang/elixir/commits/v1.17.2/lib/elixir/lib/list/chars.ex
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+defimpl List.Chars, for: List do
+  # Note that same inlining is used for the rewrite rule.
+  def to_charlist(list), do: list
+end

libs/exavmlib/lib/List.Chars.ex

@@ -0,0 +1,39 @@
+#
+# This file is part of elixir-lang.
+#
+# Copyright 2013-2023 Elixir Contributors
+# https://github.com/elixir-lang/elixir/commits/v1.17.2/lib/elixir/lib/list/chars.ex
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+defprotocol List.Chars do
+  @moduledoc ~S"""
+  The `List.Chars` protocol is responsible for
+  converting a structure to a charlist (only if applicable).
+
+  The only function that must be implemented is
+  `to_charlist/1` which does the conversion.
+
+  The `to_charlist/1` function automatically imported
+  by `Kernel` invokes this protocol.
+  """
+
+  @doc """
+  Converts `term` to a charlist.
+  """
+  @spec to_charlist(t) :: charlist
+  def to_charlist(term)
+end