[comp.sys.mac.hypercard] 2.0 WishList

tomj@oakhill.UUCP (Tom Johnson) (09/23/88)

In article <17439@apple.Apple.COM> dan@apple.com.UUCP (Dan Allen) writes:
>In article <3047@pt.cs.cmu.edu> ns@cat.cmu.edu (Nicholas Spies) writes:
>>IsADigit(c) -- return true if c is a digit
>>....several deleted neat ideas...
>>ParseFrom(text,string) -- return text from any character in string
>
>Good ideas.  We'll see what we can do for 2.0...
>
>Dan Allen
>Apple

While we are (now) on the subject...how about a little help for those
of us who would like to test for the presence of a file or volume
(or MacServe, TOPS, or AppleShare partition) **prior** to attempting
to open a file and have the open request trapped by Hypercard?  This is
a problem when you are attempting to design a stack for people who have
only a vague idea of what a file **is**, much less where it lives.  It
sure would be handy to be able to code a script something like:
   if FExists(fname) then
	--do file stuff here
   endif
or:
   if VExists(volume_name) and FExists(volume_name&":"&path&":"&fname) then
        --ditto above
   else 
	beep
	answer "You must mount the volume" && volume_name
   endif

That's my 3.295 cents worth.
|Standard Disclaimer
|Tom Johnson
|tomj@oakhill.UUCP

ns@cat.cmu.edu (Nicholas Spies) (09/23/88)

Is there a way to tell whether you can evaluate the contents of a field
(with "the value of") to avoid getting the error dialog when "the value of"
fails?

In general, HyperCard errors of all types should be trappable, instead of
giving an unwelcome dialog warning. How about an "error" system message,
so an "on error" handler could be written to handle illegal user inputs
gracefully. The system does it already, in some sense, to provide the dialog
boxes...


-- 
Nicholas Spies			ns@cat.cmu.edu.arpa
Center for Design of Educational Computing
Carnegie Mellon University