basic/step1_read_print.in.bas

   1 GOTO MAIN
   2
   3 REM $INCLUDE: 'mem.in.bas'
   4 REM $INCLUDE: 'types.in.bas'
   5 REM $INCLUDE: 'readline.in.bas'
   6 REM $INCLUDE: 'reader.in.bas'
   7 REM $INCLUDE: 'printer.in.bas'
   8
   9 REM $INCLUDE: 'debug.in.bas'
  10
  11 REM READ(A$) -> R
  12 MAL_READ:
  13   GOSUB READ_STR
  14   RETURN
  15
  16 REM EVAL(A, E) -> R
  17 SUB EVAL
  18   R=A
  19 END SUB
  20
  21 REM PRINT(A) -> R$
  22 MAL_PRINT:
  23   AZ=A:B=1:GOSUB PR_STR
  24   RETURN
  25
  26 REM REP(A$) -> R$
  27 SUB REP
  28   GOSUB MAL_READ
  29   IF ER<>-2 THEN GOTO REP_DONE
  30
  31   A=R:CALL EVAL
  32   IF ER<>-2 THEN GOTO REP_DONE
  33
  34   A=R:GOSUB MAL_PRINT
  35
  36   REP_DONE:
  37     REM Release memory from EVAL
  38     AY=R:GOSUB RELEASE
  39 END SUB
  40
  41 REM MAIN program
  42 MAIN:
  43   GOSUB INIT_MEMORY
  44
  45   ZT=ZI: REM top of memory after base repl_env
  46
  47   REPL_LOOP:
  48     A$="user> ":GOSUB READLINE: REM call input parser
  49     IF EZ=1 THEN GOTO QUIT
  50     IF R$="" THEN GOTO REPL_LOOP
  51
  52     A$=R$:CALL REP: REM call REP
  53
  54     IF ER<>-2 THEN GOSUB PRINT_ERROR:GOTO REPL_LOOP
  55     PRINT R$
  56     GOTO REPL_LOOP
  57
  58   QUIT:
  59     REM GOSUB PR_MEMORY_SUMMARY_SMALL
  60     #cbm END
  61     #qbasic SYSTEM
  62
  63   PRINT_ERROR:
  64     PRINT "Error: "+E$
  65     ER=-2:E$=""
  66     RETURN
  67