Handle block comments in Lua.

dcs/lua/parse.py

@@ -346,6 +346,12 @@ def eat_line(self) -> None:
             while not self.eob() and self.char() != '\n':
                 self.pos += 1
 
+        def eat_block_comment(self) -> None:
+            while not self.eob() and self.next_n_chars(4) != "--]]":
+                self.pos += 1
+            if not self.eob():
+                self.pos += 4
+
         def eat_ws(self):
             """
             Advances the internal buffer until it reaches a non comment or whitespace.
@@ -357,7 +363,10 @@ def eat_ws(self):
                 c: str = self.char()
                 if c == '\n':
                     self.lineno += 1
-                if c == '-' and self.char(lookahead=1) == '-':
+                if self.next_n_chars(4) == "--[[":
+                    self.eat_block_comment()
+                    continue
+                if self.next_n_chars(2) == "--":
                     self.eat_line()
                     continue
                 if not c.isspace():
@@ -389,6 +398,9 @@ def char(self, lookahead: int = 0) -> str:
             except IndexError as ex:
                 raise self.eob_exception(lookahead) from ex
 
+        def next_n_chars(self, n: int) -> str:
+            return self.buffer[self.pos:self.pos + n]
+
         def advance(self) -> bool:
             """
             Advances the internal buffer position by 1 and checks if we are at the end of buffer.

dcs/lua/test_parse.py

@@ -290,6 +290,20 @@ def test_whitespace_can_end_with_comment_before_eof(self) -> None:
         # and only if they were not preceded by whitespace.
         loads('\n--')
 
+    def test_block_comment(self) -> None:
+        r = loads(
+            textwrap.dedent(
+                """\
+                --[[
+                this is a comment
+                --]]foo = "bar"
+                """
+            )
+        )
+        self.assertEqual(r["foo"], "bar")
+
+        loads("--[[ Old Bort Calls For 1.5.3 and Older ]]--")
+
 
 if __name__ == '__main__':
     unittest.main()