python/step1_read_print.py

   1 import sys, traceback
   2 import mal_readline
   3 import mal_types as types
   4 import reader, printer
   5
   6 # read
   7 def READ(str):
   8     return reader.read_str(str)
   9
  10 # eval
  11 def EVAL(ast, env):
  12         #print("EVAL %s" % ast)
  13         return ast
  14
  15 def PRINT(exp):
  16     return printer._pr_str(exp)
  17
  18 # repl
  19 def REP(str):
  20     return PRINT(EVAL(READ(str), {}))
  21
  22 while True:
  23     try:
  24         line = mal_readline.readline("user> ")
  25         if line == None: break
  26         if line == "": continue
  27         print(REP(line))
  28     except reader.Blank: continue
  29     except Exception as e:
  30         print("".join(traceback.format_exception(*sys.exc_info())))