rexx/step1_read_print.rexx

   1 call main
   2 exit
   3
   4 #include "readline.rexx"
   5 #include "reader.rexx"
   6 #include "printer.rexx"
   7
   8 read: procedure expose values. err /* read(str) */
   9   return read_str(arg(1))
  10
  11 eval: procedure expose values. /* eval(exp, env) */
  12   return arg(1)
  13
  14 print: procedure expose values. /* print(exp) */
  15   return pr_str(arg(1), 1)
  16
  17 rep: procedure expose values. env. err /* rep(str) */
  18   ast = read(arg(1))
  19   if ast == "ERR" then return "ERR"
  20   exp = eval(ast)
  21   return print(exp)
  22
  23 main:
  24   values. = ""
  25   values.0 = 0
  26   do while lines() > 0 /* 1 == 1 */
  27     input_line = readline('user> ')
  28     if length(input_line) > 0 then do
  29       res = rep(input_line)
  30       if res == "ERR" then
  31         call lineout , "Error: " || err
  32       else
  33         call lineout , res
  34     end
  35   end