old_contents: def _generate_tables_impl(ctx):
      args = ctx.actions.args()
      args.add("-input", ctx.file.src)
      args.add("-output", ctx.outputs.out)
      ctx.actions.run(
          executable = ctx.executable.bin,
          inputs = [ctx.file.src],
          outputs = [ctx.outputs.out],
          arguments = [args],
      )
  
  generate_tables = rule(
      implementation = _generate_tables_impl,
      attrs = {
          "src": attr.label(allow_single_file=True),
          "out": attr.output(),
          "bin": attr.label(
              default = "//generatetables",
              executable = True,
              allow_single_file = True,
              cfg = "host",
          ),
      },
  )
  
new_contents: def _generate_tables_impl(ctx):
      args = ctx.actions.args()
      args.add("-input", ctx.file.src)
      args.add("-output", ctx.outputs.out)
      ctx.actions.run(
          executable = ctx.executable.bin,
          inputs = [ctx.file.src],
          outputs = [ctx.outputs.out],
          arguments = [args],
      )
  
  generate_tables = rule(
      implementation = _generate_tables_impl,
      attrs = {
          "src": attr.label(allow_single_file = True),
          "out": attr.output(),
          "bin": attr.label(
              default = "//generatetables",
              executable = True,
              allow_single_file = True,
              cfg = "host",
          ),
      },
  )
  
subject: Fix file format (#848)