Text Adventure.bs2

' {$STAMP BS2}
' {$PBASIC 2.5}

Speaker      PIN 4
MAX_INPUT    CON 10

sInputBuff   VAR Byte(MAX_INPUT)  'input buffer
byKeyIn      VAR Byte             'Key read from terminal
byCurPos     VAR Byte             'cursor position/input length
byLinePos    VAR Byte             'position in line we're printing
byCharIn     VAR byKeyIn          'Reuse KeyIn for reading strings to output
wStrPtr      VAR Word             'pointer to string

bOutType     VAR Bit              'what we'll print, 0 = room description, 1 = other
nDescription VAR Nib              'Description to type
nCommand     VAR nDescription     'comand to compare against
nRoom        VAR Nib              'Stores room we're in

'---- Room Descriptions ----'
Room1 DATA "You find yourself in a dimly lit dungeon, exits are NORTH, SOUTH and WEST.", 0
Room2 DATA "North room"
'---- Other Descriptions ----'
UnknownCommand DATA "I don't know what you're saying...", 0
DSC_NOT_COMMAND CON 0

DO
  byCurPos = 0 'reset input length to 0
  GOSUB ReadInput

  GOSUB CheckInput
LOOP
END

'Command strings
CmdLook DATA "LOOK", 0
'and lookup constants
CMD_LOOK CON 0
CMD_NONE CON 1   'always must be last

bFoundMatch VAR Bit
CheckInput:
  nCommand = CMD_LOOK
  GOSUB CompareStrings

  SELECT nCommand
  CASE CMD_LOOK
    bOutType = 0 'print room
  CASE CMD_NONE
    nDescription = DSC_NOT_COMMAND
    bOutType = 1
  ENDSELECT
  GOSUB TypeDescription
RETURN

CompareStrings:
  DO
    bFoundMatch = 1 'all are match until otherwise proven
    LOOKUP nCommand, [CmdLook], wStrPtr
    FOR byLinePos = 0 TO byCurPos - 1
      READ wStrPtr + byLinePos, byCharIn
      IF byCharIn <> sInputBuff(byLinePos + 1) THEN
        bFoundMatch = 0           'not a match
        nCommand = nCommand + 1   'move to next one
        EXIT
      ENDIF
    NEXT
    IF bFoundMatch THEN RETURN
   LOOP UNTIL nCommand = CMD_NONE
RETURN

TypeDescription:
  byLinePos = 0 'start at begin of line

  IF bOutType = 0 THEN  'Room description
    LOOKUP (nRoom), [Room1, Room2], wStrPtr
  ELSE                  'Describe something else
    SELECT nDescription
    CASE DSC_NOT_COMMAND
      wStrPtr = UnknownCommand
    ENDSELECT
  ENDIF

  DO
    READ wStrPtr, byCharIn
    IF byCharIn <> 0 THEN
      DEBUG byCharIn
    ENDIF
    wStrPtr = wStrPtr + 1
  LOOP UNTIL byCharIn = 0

  DEBUG 13, ">"
RETURN


ReadInput:
  DEBUGIN byKeyIn      'read key in

  IF byKeyIn = 8 THEN      'backspace
    sInputBuff(byCurPos) = 0
    IF byCurPos > 0 THEN
      byCurPos = byCurPos - 1
    ELSE
      DEBUG ">"
    ENDIF
    GOTO ReadInput
  ELSEIF byKeyIn = 13 THEN 'return
    RETURN
  ENDIF

  'make sure input doesn't overflow
  IF byCurPos < MAX_INPUT THEN
    byCurPos = byCurPos + 1
  ELSE                          'hit end of input buffer!
    DEBUG 8                     'backspace
    FREQOUT Speaker, 125, 3000  'beep
    GOTO ReadInput              'Go back to input
  ENDIF

  'Do stuff based on char read
  SELECT byKeyIn
  CASE "a" TO "z"
    sInputBuff(byCurPos) = (byKeyIn - 32) 'convert to upper case

  CASE "A" TO "Z"
    sInputBuff(byCurPos) = byKeyIn

  CASE ELSE
    DEBUG 8                     'don't accept non-text characters
    FREQOUT Speaker, 125, 3000  'beep
  ENDSELECT

GOTO ReadInput 'loop until return