hello, the problem is that the create function in the controller is giving me problems:
unexpected operator ->. If you want to define multiple clauses, the first expression must use ->. Syntax error before: '->'
(elixir 1.10.3) lib/kernel/parallel_compiler.ex:304: anonymous fn/4 in Kernel.ParallelCompiler.spawn_workers/7
this is my controller:
def create(conn, params) do
with {:ok, request} <- handle.map(params) do
Project.ProjectBuilderSupervisor.build_receipt(request)
conn
|> put_status(:ok)
|> render("ok.json")
error ->
conn |> put_status(:bad_request) |> put_view(ProjectWeb.ErrorView) |> render(:"400")
end
end
The error is informing you that with is not the right solution: since you have only a single clause, and an else branch, your code is better written using a case:
def create(conn, params) do
case handle.map(params) do
{:ok, request} ->
Project.ProjectBuilderSupervisor.build_receipt(request)
conn
|> put_status(:ok)
|> render("ok.json")
_ ->
conn |> put_status(:bad_request) |> put_view(ProjectWeb.ErrorView) |> render(:"400")
end
end
As @kokolegorille said, with is used in situations when you have a chain of several clauses, each of which could give an error, and you want to break out from the chain on the first error:
with {:ok, foo} <- Map.fetch(options, :foo),
{:ok, bar} <- Map.fetch(options, :bar) do
# ...do something with foo and bar
else
:error ->
# ...handle error
end
In your case, with is not necessary, and ends up being more cumbersome. Therefore the message tells you to use case instead.
