{-
https://raw.githubusercontent.com/BSVLang/Main/master/Tutorials/Bluespec_Classic_Training/Examples/Eg02_HelloWorld.pdf
 -}
package Top where

-- module name is mkTop
-- Empty is the interface part.
-- mkTop module has no interface. ie, no methods.
-- So it cannot interact with its environment.
mkTop :: Module Empty

-- mkTop's definition
mkTop =
  module
    rules
      -- a rule named `"rl_print_answer"`
      -- Here, always executed because of the True, I guess.
      "rl_print_answer": when True ==> do

          -- `$display` prints messages (with a newline appended)
          $display "Hello, World!"
          $display "answer is: %0d (or, in hex: 0x%0h)\n"  42  42

          -- halts whole simulation to terminate. So, this rule can fire only once
          $finish