Hi,

I am trying to define a parser for a simple grammar and I am getting hung up on something that I think is simple but I can’t figure out.

The grammar has two main structures, a definition and an invocation, of the form:

invocationname($a$b)(c<>d<>)
definitionname[(a<>b<>)($c$d)somestuff:someotherstuff]

I have the invocation one working, but for some reason even though the definition structure is very similar, I get an error that it is expecting the opening bracket, even though I am sending it.

The whole parser definition is here, and I will copy my interaction with it:

defmodule Atomix.Invocation.Parser do
  import NimbleParsec

  name = ascii_string([?A..?z], min: 1)

  definition_name = ascii_string([?A..?z], min: 1)

  invocation_name = ascii_string([?a..?z], min: 1)

  content_name = ascii_string([?A..?Z], min: 1)

  destination_place =
    string("$")
    |> concat(name)

  destination_list =
    destination_place
    |> repeat(destination_place)

  source_place =
    name
    |> string("<>")

  source_list =
    source_place
    |> repeat(source_place)

  place_of_resolution =
    string("+")

  contained_definitions =
    string("=")


  defparsec(
    :invocation,
    invocation_name
    |> string("(")
    |> concat(destination_list)
    |> string(")")
    |> string("(")
    |> concat(source_list)
    |> string(")")
  )

  defparsec(
    :definition,
    definition_name
    |> string("[")
    |> concat(source_list)
    |> concat(destination_list)
    |> concat(place_of_resolution)
    |> string(":")
    |> concat(contained_definitions)
    |> string("]")
  )
end

iex(2)> Parser.invocation(“dfsd($a$b)(a<>b<>)”)
{:ok, [“dfsd”, “(”, “$”, “a”, “$”, “b”, “)”, “(”, “a”, “<>”, “b”, “<>”, “)”],
“”, %{}, {1, 0}, 18}
iex(3)> Parser.definition(“fdafa[(a<>b<>)fdsaf:fadf]”)
{:error, “expected string "["”, “(a<>b<>)fdsaf:fadf]”, %{}, {1, 0}, 6}

Why am I getting the error about expecting the bracket when it is clearly there?
Thanks for any pointers.