var opt_check = new OptionBool("Check format of Nit source files", "--check")
end
# Return result from diff between `file1` and `file2`.
private fun diff(file1, file2: String): String do
var opt_check = new OptionBool("Check format of Nit source files", "--check")
end
# Return result from diff between `file1` and `file2`.
private fun diff(file1, file2: String): String do