gitignore.livemd

Orb .gitignore Parser

Mix.install([
  {:orb, "~> 0.0.41"},
  {:wasmex, "~> 0.8.3"}
])

Define our gitignore parser module using Orb

defmodule GitIgnoreParser do
  use Orb

  SilverOrb.Lines.def GitIgnoreLineOffsetsSorted, pages: 1

  SilverOrb.Input.Lines.def GitIgnoreContent, pages: 1, export_write: :write_gitignore do
    for line <- GitIgnoreContent.lines() do
      GitIgnoreLineOffsetsSorted.insert(line.slice)
    end
    GitIgnoreLineOffsetsSorted.sort()
  end

  SilverOrb.Input.def Path, export_write: :write_path, pages: 1

  defw ignored?(), I32 do
    for line <- GitIgnoreLineOffsetsSorted.lines() do
      local order = evaluate_line(line, Path) do
        case order do
          # before
          -1 ->
            # continue
            nop()

          # after
          1 ->
            return(i32(0))
          
          # matches
          0 ->
            return(i32(1))
        end
      end
    end
  end

  defwp evaluate_line(line: SilverOrb.Input.Line) do
    
  end
end

We can compile this module to the WebAssembly text format

Orb.to_wat(GitIgnoreParser)
|> IO.puts()

We can run the WebAssembly module in Elixir using Wasmex

{:ok, pid} = Wasmex.start_link(%{bytes: Orb.to_wat(GitIgnoreParser)})

{:ok, [start, length]} = Wasmex.call_function(pid, :write_gitignore_slice, [])
write_string(pid, :write_gitignore, start, length, ".DS_Store\ntmp/\nnode_modules/")

{:ok, [start, length]} = Wasmex.call_function(pid, :write_path_slice, [])
write_string(pid, :write_path, start, length, "some-file-name")

{:ok, [ignored?]} = Wasmex.call_function(pid, :ignored?, [])
IO.inspect(ignored?, label: "ignored?")