assert

[Graham Samuel]

Richmond, I did your thing of creating a button with a script in it:

on mouseUp
   assert 1 is 2
end mouseUp

on assertError
   answer "It isn't, you know!"
end assertError

It worked entirely as expected - the object containing the command (the button, in this case) received the assertError message as per the description. However I am still extremely unsure where I would use it in place of try-catch, but FWIW it does work.

Graham

On 23 Feb 2014, at 16:55, Richmond <richmondmathewson at gmail.com> wrote:

> On 23/02/14 15:47, Björnke von Gierke wrote:
>> on mouseUp
>>   assert 1 + "blah"
>> end mouseUp
> 
> Well that certainly threw up an error message.
> 
> But this:
> 
> on mouseUp
>    put 1 + "blah" into FUDGE
> end mouseUp
> 
> also threw up an error message.
> --------------------------------------------------
>> on assertError dont, remember, amountOfParameters
>>   put dont & remember & amountOfParameters
>> end assert
> 
> When I tried to put that one in my button I got this:
> 
> button "Button": compilation error at line 8 (Handler: end doesn't match handler name) near "assert", char 1
> 
> in the scriptEditor when I tried to apply it.
> 
> --------------------------------------------------------
> 
> When I tried this:
> 
> on assertError dont, remember, amountOfParameters
>  put dont & remember & amountOfParameters
> end assertError
> 
> NOTHING appeared in the Message Box.
> 
> Richmond.
> 
>> 
>> see release notes of 6.6 dp here: http://downloads.livecode.com/livecode/
>> 
>> On 23.02.2014, at 14:31, Richmond <richmondmathewson at gmail.com> wrote:
>> 
>>> Right; so here I am on a Sunday afternoon feeling
>>> suitably postprandial . . . and looking at the notes for 6.6 dp1
>>> and playing around with ASSERT
>>> 
>>> Set up a stack with a button with this script:
>>> 
>>> on mouseUp
>>>   assert 1 is 2
>>> end mouseUp
>>> 
>>> as per notes.
>>> 
>>> SO? Where is any sort of result????
>>> 
>>> tried this script:
>>> 
>>> on mouseUp
>>>   put assert (1 is 2) into fld "fOUT"
>>> end mouseUp
>>> 
>>> that one "threw a bluey"
>>> 
>>> as did:
>>> 
>>> on mouseUp
>>>   put assert (1 is 2)
>>> end mouseUp
>>> 
>>> So, I made another button with this script:
>>> 
>>> on mouseUp
>>>   if 1 is 2 then
>>>      put "Yup" into fld "fOUT"
>>>   else
>>>      put "Nope" into fld "fOUT"
>>>      end if
>>> end mouseUp
>>> 
>>> which worked perfectly.
>>> 
>>> ---------------------------------------------
>>> 
>>> SO; assert is meant to be a way to check for runtime errors
>>> 
>>> [which in my example above it certainly does NOT look like]
>>> 
>>> WHERE is one expected to see "fails" or "succeeds"
>>> 
>>> or, how does one know if assert has either failed or succeeded?
>>> 
>>> --------------------------------------------
>>> 
>>> Why not just run one's original script and see it the da*n things works?
>>> 
>>> -------------------------------------------
>>> 
>>> "if the condition fails, then an assertError message is sent to the object containing the
>>> command"
>>> 
>>> Where does the programmer see the assertError message?
>>> 
>>> ------------------------------------------
>>> 
>>> Richmond.
>>> 
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>> 
> 
> 
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