handle embedded script payload

corpus/payload.txt

@@ -0,0 +1,25 @@
+==================
+nix-shell with a bash payload
+==================
+
+#!/usr/bin/env nix-shell
+#!nix-shell -i bash
+echo "hello, world!"
+---
+
+(source_file
+  (first_line
+    (shebang_open)
+    (opt_ws)
+    (env)
+    (ws)
+    (nix_shell))
+  (next_line
+    (newline)
+    (annotation_line
+      (shebang_open)
+      (opt_ws)
+      (nix_shell)
+      (nix_shell_args)))
+  (next_line
+    (newline)))

corpus/shebang_with_sub_interpreter.txt

@@ -13,7 +13,7 @@ Minimal nix-shell invocation
     (env)
     (ws)
     (nix_shell))
-  (non_first_line
+  (next_line
     (newline)
     (annotation_line
       (shebang_open)

grammar.js

@@ -2,18 +2,28 @@ module.exports = grammar({
   name: 'nixshell',
 
   rules: {
-    source_file: $ => seq($.first_line, repeat($.non_first_line)),
+    source_file: $ => seq($.first_line, repeat($.next_line)),
 
     first_line: $ => seq($.shebang_open, $.opt_ws, optional(seq($.env, $.ws)), $.nix_shell),
-    non_first_line: $ => seq($.newline, $.annotation_line),
+    next_line: $ => seq($.newline, choice(
+        $.annotation_line,
+        // TODO: capture this
+        repeat(/./),
+    )),
     annotation_line: $ => seq($.shebang_open, $.opt_ws, $.nix_shell, $.nix_shell_args),
-    embedded_script_line: $ => /.*/,
+    // payload_next_line: $ => /\n.*/,
+    // payload_line: $ => /.*/,
+    // payload_line: $ => repeat(/./),
 
-    shebang_open: $ => /#!/,
+    // nix_shell_directive_open: $ => '#!nix-shell',
+    // TODO: actually parse nix-shell arguments
+    nix_shell_args: $ => ' -i bash',
+
+    // TODO: hide these (prefix with underscore)
+    shebang_open: $ => '#!',
     // TODO: allow `usr/bin/env`, `env`
     env: $ => '/usr/bin/env',
     nix_shell: $ => 'nix-shell',
-    nix_shell_args: $ => ' -i bash',
     ws: $ => / +/,
     opt_ws: $ => / */,
     newline: $ => '\n',