docs and build shit

.gitignore

@@ -2,3 +2,7 @@
 *.ez
 /build
 erl_crash.dump
+.DS_Store
+*.swp
+*.swo
+luma_markdown

README.md

@@ -3,22 +3,78 @@
 [![Package Version](https://img.shields.io/hexpm/v/luma_markdown)](https://hex.pm/packages/luma_markdown)
 [![Hex Docs](https://img.shields.io/badge/hex-docs-ffaff3)](https://hexdocs.pm/luma_markdown/)
 
+`luma_markdown` converts Luma markup to Markdown. It can read a file or consume
+all of its input from standard input.
+
+## Standalone executable
+
+Gleam can package the Erlang version of the program as an escript. An escript
+is one executable file containing the compiled program and its dependencies
+(it does require Erlang to be installed on the machine where it is run).
+
+From the project directory, run:
+
 ```sh
-gleam add luma_markdown@1
-```
-```gleam
-import luma_markdown
-
-pub fn main() -> Nil {
-  // TODO: An example of the project in use
-}
+gleam export escript
+chmod +x luma_markdown
 ```
 
-Further documentation can be found at <https://hexdocs.pm/luma_markdown>.
+This creates the single executable `./luma_markdown`. Re-run the export
+command after changing the source. To use a different filename, rename the
+generated file:
+
+```sh
+mv luma_markdown luma-md
+```
+
+Pass a file path as the only argument:
+
+```sh
+./luma_markdown input.luma
+```
+
+Or pipe content into it. The command receiving the pipe must come last:
+
+```sh
+echo "#1 A heading" | ./luma_markdown
+cat input.luma | ./luma_markdown
+```
+
+When using a shell with history expansion (such as interactive zsh), use
+single quotes or `printf` for input beginning with `!`:
+
+```sh
+printf '%s\n' '!4 emphasized text' | ./luma_markdown
+```
+
+With no arguments, the executable reads until standard input reaches EOF and
+writes the resulting Markdown to standard output.
+
+## Neovim preview
+
+The working preview configuration is also included in
+[`examples/neovim_luma_preview.lua`](examples/neovim_luma_preview.lua). Copy it
+into your Neovim configuration or source it with:
+
+```lua
+dofile(vim.fn.getcwd() .. "/examples/neovim_luma_preview.lua")
+```
+
+The snippet looks for `luma_markdown` on `PATH`. To use the executable in this
+repository directly, set its path before starting Neovim:
+
+```sh
+export LUMA_MARKDOWN_BIN="$PWD/luma_markdown"
+```
+
+It registers the `:LumaPreview` command and automatically refreshes the
+preview for `*.luma` files.
 
 ## Development
 
 ```sh
-gleam run   # Run the project
-gleam test  # Run the tests
+gleam run -- input.luma  # Run from the Gleam toolchain
+gleam test               # Run the tests
 ```
+
+Further documentation can be found at <https://hexdocs.pm/luma_markdown>.

examples/neovim_luma_preview.lua

@@ -0,0 +1,52 @@
+-- Neovim preview for Luma files.
+--
+-- Set LUMA_MARKDOWN_BIN to the path of the generated executable, or make
+-- luma_markdown available on PATH:
+--   export LUMA_MARKDOWN_BIN="$PWD/luma_markdown"
+
+local preview_buf = nil
+local preview_win = nil
+
+local function update_luma_preview()
+  local src_buf = vim.api.nvim_get_current_buf()
+  local lines = vim.api.nvim_buf_get_lines(src_buf, 0, -1, false)
+  local cmd = vim.env.LUMA_MARKDOWN_BIN or "luma_markdown"
+  local output = vim.fn.systemlist(cmd, lines)
+
+  if not preview_buf or not vim.api.nvim_buf_is_valid(preview_buf) then
+    preview_buf = vim.api.nvim_create_buf(false, true)
+    vim.api.nvim_buf_set_option(preview_buf, "buftype", "nofile")
+    vim.api.nvim_buf_set_option(preview_buf, "bufhidden", "hide")
+    vim.api.nvim_buf_set_option(preview_buf, "swapfile", false)
+    vim.api.nvim_buf_set_option(preview_buf, "filetype", "markdown")
+  end
+
+  vim.api.nvim_buf_set_lines(preview_buf, 0, -1, false, output)
+
+  if not preview_win or not vim.api.nvim_win_is_valid(preview_win) then
+    vim.cmd "rightbelow vsplit"
+    preview_win = vim.api.nvim_get_current_win()
+    vim.api.nvim_win_set_buf(preview_win, preview_buf)
+
+    local src_win = vim.fn.bufwinid(src_buf)
+    if src_win ~= -1 then vim.api.nvim_set_current_win(src_win) end
+  end
+end
+
+vim.api.nvim_create_autocmd("BufWritePost", {
+  pattern = "*.luma",
+  callback = update_luma_preview,
+})
+
+vim.api.nvim_create_user_command("LumaPreview", update_luma_preview, {})
+
+local timer = nil
+local function debounced_update()
+  if timer then timer:stop() end
+  timer = vim.defer_fn(update_luma_preview, 150)
+end
+
+vim.api.nvim_create_autocmd({ "TextChanged", "TextChangedI" }, {
+  pattern = "*.luma",
+  callback = debounced_update,
+})

src/helpers.gleam

@@ -18,8 +18,6 @@ pub fn gather(instructions: List(definition.Instruction)) -> Information {
         _ -> Error(Nil)
       }
     })
-  echo pushes
-
   let min_max = case pushes {
     [] -> Error(Nil)
     [first, ..rest] ->

src/luma_markdown.gleam

@@ -11,8 +11,6 @@ pub fn luma_markdown(
   information: helpers.Information,
   contents: String,
 ) -> String {
-  echo contents
-  echo information
   let lines = string.split(contents, "\n")
 
   let parsed =
@@ -37,7 +35,7 @@ pub fn luma_markdown(
                     definition.Truth(instruction) ->
                       string.repeat("__", instruction)
                   }
-                definition.Pop(instruction) -> "##"
+                definition.Pop(_) -> "##"
               }
             }),
             "",
@@ -53,21 +51,37 @@ pub fn main() -> Nil {
     [filename] -> {
       case simplifile.read(filename) {
         Ok(contents) -> {
-          //programm goes here
-          let instructins = parser.handler(contents)
-          let information = case instructins {
-            // get informations
-            definition.TextInstructions(instruction) ->
-              helpers.gather(instruction)
-          }
-          echo information
-          let result = luma_markdown(information, contents)
-          io.println(result)
+          render(contents)
+        }
+        Error(_) -> {
+          io.println("Couldn't read file: " <> filename)
           Nil
         }
-        Error(_) -> io.println("Couldn't read file")
       }
     }
-    _ -> io.println("Usage: gleam run <file>")
+    [] -> render(read_stdin([]))
+    _ -> {
+      io.println("Usage: luma_markdown [file]")
+      Nil
+    }
+  }
+}
+
+fn render(contents: String) -> Nil {
+  let information = case parser.handler(contents) {
+    definition.TextInstructions(instructions) -> helpers.gather(instructions)
+  }
+  let result = luma_markdown(information, contents)
+  io.println(result)
+}
+
+@external(erlang, "luma_stdin", "read_line")
+fn read_line() -> String
+
+fn read_stdin(lines: List(String)) -> String {
+  let line = read_line()
+  case line {
+    "" -> lines |> list.reverse |> string.join("")
+    _ -> read_stdin([line, ..lines])
   }
 }

src/luma_stdin.erl

@@ -0,0 +1,9 @@
+-module(luma_stdin).
+
+-export([read_line/0]).
+
+read_line() ->
+    case io:get_line("") of
+        eof -> <<>>;
+        Line -> unicode:characters_to_binary(Line)
+    end.