'===========================================================================
' Subject: FILTER OUT CHOICES FROM LIST      Date: 12-11-99 (12:41)       
' Author:  Terry Simonds                     Code: QB, QBasic, PDS        
' Origin:  fsimonds@gate.net               Packet: MISC.ABC
'===========================================================================
DECLARE SUB Continue ()
'  FILTER.BAS
'  Returns a single key from a predermined list of choices.
  
'     Allows the system clock to be
'     used to display seconds while you're waiting at this screen.
'
'  **********************************************************
'  *  Written by Terry Simonds/WB4FXD    fsimonds@gate.net  *
'  **********************************************************
'
'
'  The code in the main part of this is for demonstration only.
'  Filtering is done in the Sub
'
DECLARE SUB Filter ()

COMMON SHARED k$, k

Start:
COLOR 15, 1: CLS

LOCATE 8, 10: PRINT TIME$      '  "NOT PART OF FILTER: FOR DEMO ONLY"

LOCATE 10, 10
PRINT "Select Option ("; : COLOR 14, 1: PRINT "e"; : COLOR 15, 1
PRINT "dit   "; : COLOR 14, 1: PRINT "d"; : COLOR 15, 1
PRINT "elete   "; : COLOR 14, 1: PRINT "p"; : COLOR 15, 1
PRINT "rint)"

' ********************************************************************

k$ = "PDE+Q": Filter       'k$ defines the permissable choices

ON k GOTO Prnt, Dele, Edit, Enter, Quit   'Steering after valid choice

' ********************************************************************
'
'       The above, with the sub, is the guts of the thing


Prnt:
LOCATE 12, 10
PRINT "You chose to Print... ("; k$; "), position"; k
Continue
GOTO Start

Dele:
LOCATE 12, 10
PRINT "You chose to Delete... ("; k$; "), position"; k
Continue
GOTO Start

Edit:
LOCATE 12, 10
PRINT "You chose to Edit... ("; k$; "), position"; k
Continue
GOTO Start

Enter:
LOCATE 12, 10
PRINT "You hit the Enter key... ( CHR$(13) ), position"; k
Continue
GOTO Start

Quit:
LOCATE 12, 10
PRINT "You chose to quit... ("; k$; "), position"; k
END

SUB Continue
LOCATE 14, 10
COLOR 12, 1
PRINT "Press any key to restart... (q to quit)"
COLOR 15, 1

DO
  LOCATE 8, 10: PRINT TIME$      '  "NOT PART OF FILTER: FOR DEMO ONLY"
LOOP UNTIL INKEY$ <> ""

END SUB



SUB Filter


IF INSTR(k$, "+") > 0 THEN MID$(k$, INSTR(k$, "+"), 1) = CHR$(13)
      'The "+" sign  allows the "Enter" (Chr$(13) key to be valid
      'as well as the listed choices. Use when you want "Enter" to
      'be the default to, say, a "Yes" or an "OK" choice.

TryAgain:
DO:
  trap$ = UCASE$(INKEY$)
  LOCATE 8, 10: PRINT TIME$      '  "NOT PART OF FILTER: FOR DEMO ONLY"
LOOP WHILE trap$ = ""   '

IF INSTR(k$, trap$) THEN         'If the keystroke was on on the list
  k = INSTR(k$, trap$)           'then exit the sub with the key
  k$ = RIGHT$(trap$, 1)          'that was hit and its position
  EXIT SUB                       'in the permissible-choice string (k$)
END IF


GOTO TryAgain                    'Wrong key--try again

END SUB