process/step1_read_print.txt

   1 --- step1_read_print ----------------------------
   2 import reader, printer
   3
   4 READ(str): return reader.read_str(str)
   5
   6 EVAL(ast,env): return ast
   7
   8 PRINT(exp): return printer.pr_str(exp)
   9
  10 rep(str): return PRINT(EVAL(READ(str),""))
  11
  12 main loop:
  13   try:      println(rep(readline("user> ")))
  14   catch e:  println("Error: ", e)