Fix mix test for when using Elixir 1.18.4

.travis.yml

@@ -5,6 +5,8 @@ notifications:
     - ben.wilson@cargosense.com
 matrix:
   include:
+    - elixir: 1.18.4
+      otp_release: 28.0
     - elixir: 1.6
       otp_release: 21.0
     - elixir: 1.7

lib/vex/struct.ex

@@ -3,25 +3,63 @@ defmodule Vex.Struct do
 
   defmacro __using__(_) do
     quote do
-      @vex_validations %{}
+      Module.register_attribute(__MODULE__, :vex_validation_specs, accumulate: true)
       @before_compile unquote(__MODULE__)
       import unquote(__MODULE__)
       def valid?(self), do: Vex.valid?(self)
     end
   end
 
-  defmacro __before_compile__(_) do
+  defmacro __before_compile__(env) do
+    specs =
+      env.module
+      |> Module.get_attribute(:vex_validation_specs, [])
+      |> Enum.reverse()
+
+    # Build the function body with pattern matching on each field
+    validation_map_ast = build_validation_map(specs)
+
     quote do
-      def __vex_validations__(), do: @vex_validations
+      def __vex_validations__() do
+        unquote(validation_map_ast)
+      end
 
       require Vex.Extract.Struct
       Vex.Extract.Struct.for_struct()
     end
   end
 
+  # Build the validation map AST at compile time
+  @spec build_validation_map([{atom(), list()}]) :: Macro.t()
+  defp build_validation_map(specs) do
+    map_contents =
+      Enum.map(specs, fn {name, validations_escaped} ->
+        # The validations are escaped, so we need to create AST that will
+        # produce them at runtime
+        {name, process_validation_list(validations_escaped)}
+      end)
+
+    {:%{}, [], map_contents}
+  end
+
+  # Process the escaped validation list to handle regex patterns
+  @spec process_validation_list(Keyword.t()) :: Keyword.t()
+  defp process_validation_list(validations_escaped) do
+    # Create AST that will build the list at runtime
+      Enum.map(validations_escaped, fn
+        {:format, {:sigil_r, meta, args}} ->
+          # This is an escaped regex, convert it back to runtime regex creation
+          {:format, {:sigil_r, meta, args}}
+
+        {key, value} ->
+          {key, value}
+      end)
+  end
+
   defmacro validates(name, validations \\ []) do
     quote do
-      @vex_validations Map.put(@vex_validations, unquote(name), unquote(validations))
+      # Store the raw validations - they'll be processed at compile time
+      @vex_validation_specs {unquote(name), unquote(Macro.escape(validations))}
     end
   end
 end