From 9d8cedd2d45b435bf5e9b957ceea7f451de9c4f4 Mon Sep 17 00:00:00 2001
From: Marlus Saraiva <marlus.saraiva@gmail.com>
Date: Wed, 18 Sep 2024 18:30:59 -0300
Subject: [PATCH] More work on removing slot :index, :name and :for

---
 lib/surface/ast.ex                 |  4 +--
 lib/surface/compiler.ex            | 54 +++++-------------------------
 lib/surface/compiler/eex_engine.ex |  9 +----
 3 files changed, 10 insertions(+), 57 deletions(-)

diff --git a/lib/surface/ast.ex b/lib/surface/ast.ex
index aab99894..ae3f7c13 100644
--- a/lib/surface/ast.ex
+++ b/lib/surface/ast.ex
@@ -332,7 +332,6 @@ defmodule Surface.AST.Slot do
 
   ## Properties
       * `:name` - the slot name
-      * `:index` - the index of the slotable entry assigned to this slot
       * `:for` - the slotable entry assigned for this slot
       * `:default` - a list of AST nodes representing the default content for this slot
       * `:arg` - quoted expression representing the argument for this slot
@@ -341,12 +340,11 @@ defmodule Surface.AST.Slot do
       * `:meta` - compilation meta data
       * `:directives` - directives associated with this slot
   """
-  defstruct [:name, :as, :for, :index, :arg, :generator_value, :context_put, :default, :meta, directives: []]
+  defstruct [:name, :as, :for, :arg, :generator_value, :context_put, :default, :meta, directives: []]
 
   @type t :: %__MODULE__{
           name: binary(),
           as: atom(),
-          index: any(),
           for: any(),
           directives: list(Surface.AST.Directive.t()),
           meta: Surface.AST.Meta.t(),
diff --git a/lib/surface/compiler.ex b/lib/surface/compiler.ex
index 792314ad..dd3ad565 100644
--- a/lib/surface/compiler.ex
+++ b/lib/surface/compiler.ex
@@ -564,43 +564,28 @@ defmodule Surface.Compiler do
         ]
       end
 
-    # TODO: Validate attributes with custom messages
-
     has_root? = has_attribute?(attributes, :root)
-    has_for? = !has_root? and has_attribute?(attributes, "for")
-
-    name =
-      extract_name_from_root(attributes) || attribute_value_as_atom(attributes, "name", nil) ||
-        extract_name_from_for(attributes)
+    name = extract_name_from_root(attributes)
 
     name =
-      if !name and !has_for? and !has_root? do
+      if !name and !has_root? do
         :default
       else
         name
       end
 
-    default_syntax? = not has_attribute?(attributes, "name") && not has_for? && not has_root?
+    default_syntax? = not has_root?
 
     render_slot_args =
       if has_root? do
         attribute_value_as_ast(attributes, :root, :render_slot, %Surface.AST.Literal{value: nil}, compile_meta)
       end
 
-    for_ast =
-      cond do
-        has_for? ->
-          attribute_value_as_ast(attributes, "for", :any, %Surface.AST.Literal{value: nil}, compile_meta)
-
-        has_root? ->
-          render_slot_args.slot
-
-        true ->
-          nil
+    slot_entry_ast =
+      if has_root? do
+        render_slot_args.slot
       end
 
-    index = attribute_value_as_ast(attributes, "index", %Surface.AST.Literal{value: 0}, compile_meta)
-
     {:ok, directives, attrs} = collect_directives(@slot_directive_handlers, attributes, meta)
     validate_slot_attrs!(attrs, meta.caller)
 
@@ -620,7 +605,7 @@ defmodule Surface.Compiler do
       maybe_warn_required_slot_with_default_value(
         slot,
         children,
-        for_ast,
+        slot_entry_ast,
         meta
       )
 
@@ -666,8 +651,7 @@ defmodule Surface.Compiler do
      %AST.Slot{
        name: name,
        as: if(slot, do: slot[:opts][:as]),
-       index: index,
-       for: for_ast,
+       for: slot_entry_ast,
        directives: directives,
        default: to_ast(children, compile_meta),
        arg: arg,
@@ -960,14 +944,6 @@ defmodule Surface.Compiler do
     node
   end
 
-  defp attribute_value_as_atom(attributes, attr_name, default) do
-    Enum.find_value(attributes, default, fn {name, value, _} ->
-      if name == attr_name do
-        String.to_atom(value)
-      end
-    end)
-  end
-
   defp attribute_raw_value(attributes, attr_name, default) do
     Enum.find_value(attributes, default, fn
       {^attr_name, {:attribute_expr, expr, _}, _} ->
@@ -978,20 +954,6 @@ defmodule Surface.Compiler do
     end)
   end
 
-  defp extract_name_from_for(attributes) do
-    with value when is_binary(value) <- attribute_raw_value(attributes, "for", nil),
-         {:ok, {:@, _, [{assign_name, _, _}]}} when is_atom(assign_name) <- Code.string_to_quoted(value) do
-      assign_name
-    else
-      {:error, _} ->
-        # TODO: raise
-        nil
-
-      _ ->
-        nil
-    end
-  end
-
   defp extract_name_from_root(attributes) do
     with value when is_binary(value) <- attribute_raw_value(attributes, :root, nil),
          {:ok, [{:@, _, [{assign_name, _, _}]} | _rest]} <-
diff --git a/lib/surface/compiler/eex_engine.ex b/lib/surface/compiler/eex_engine.ex
index 64bcdb8e..d4c33926 100644
--- a/lib/surface/compiler/eex_engine.ex
+++ b/lib/surface/compiler/eex_engine.ex
@@ -196,7 +196,6 @@ defmodule Surface.Compiler.EExEngine do
          %AST.Slot{
            name: provided_name,
            as: slot_as,
-           index: index_ast,
            for: slot_for_ast,
            arg: arg_expr,
            generator_value: generator_value_ast,
@@ -207,12 +206,6 @@ defmodule Surface.Compiler.EExEngine do
          buffer,
          state
        ) do
-    slot_index =
-      case index_ast do
-        %AST.AttributeExpr{value: expr} -> expr
-        %AST.Literal{value: value} -> value
-      end
-
     slot_for =
       case slot_for_ast do
         %AST.AttributeExpr{value: expr} -> expr
@@ -232,7 +225,7 @@ defmodule Surface.Compiler.EExEngine do
         slot_assign = {:@, [], [{slot_name, [], nil}]}
 
         quote do
-          Enum.at(List.wrap(unquote(slot_assign)), unquote(slot_index))
+          Enum.at(List.wrap(unquote(slot_assign)), 0)
         end
       end