How do i get the name of variables and its value passed to macro?

That’s not supported in Elixir at all. The only exceptions here are special forms, but they are not written in Elixir. However you can pass a list of variables instead.

Here is an example script:

defmodule Example do
  defmacro log_error(data) do
    # maps list elements returning list of quoted expressions
    ast = Enum.map(data, &quoted_kv/1)

    prefix =
      case __CALLER__ do
        %{function: nil, module: nil} ->
          ""

        %{function: nil, module: module} ->
          "[#{inspect(module)}]: "

        %{function: {function, arity}, module: module} ->
          "[#{inspect(module)}][#{function}/#{arity}]: "
      end

    quote do
      data = Enum.join([unquote_splicing(ast)], ", ")
      Logger.error(unquote(prefix) <> "Error: " <> "[[#{data}]]")
    end
  end

  # each list element is 3-element tuple
  defp quoted_kv({name, _meta, _args} = var) do
    quote do
      "#{unquote(name)}: #{unquote(var)}"
    end
  end
end

prints:

14:28:01.418 [error] [SomeModule][function_name/0]: Error: [[a: 5, b: 10, c: 15]]

Please keep in mind you have to pass all variables directly.

# won't work:
a = 5
b = 10
c = 15
list = [a, b, c]
Example.log_error(list)
# raises error

How can we create a generalized, all scenario one?
should I just pattern match? or use guards?

you can look at how stream_data does it:

https://github.com/whatyouhide/stream_data/blob/main/lib/ex_unit_properties.ex#L293-L303

For this specific problem I’d recommend solving it with an editor snippet instead of an in-project macro. I have a snippet that does a Logger.info and inspects the variable that I’m interested in.

You can use binding/1 to get the variables from a context and then inspect them. That’s how I solved interpolation in GitHub - elixir-dbvisor/sql: SQL provides state-of-the-art, high-performance SQL integration for Elixir, built to handle extreme concurrency with unmatched expressiveness and ergonomic query composition. Write safe, composable, parameterized queries directly, without translating to Ecto or any ORM. · GitHub