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From: chh9@quads.uchicago.edu (Conrad Halton Halling)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: behaviour of "it"
Message-ID: <1990Sep14.225756.4796@midway.uchicago.edu>
Date: 14 Sep 90 22:57:56 GMT
References: <1867@scott.ed.ac.uk>
Sender: news@midway.uchicago.edu (News Administrator)
Organization: University of Chicago
Lines: 62

In article <1867@scott.ed.ac.uk> marc@cogsci.ed.ac.uk (Marc Moens) writes:

> [stuff deleted]
>I wanted to create a button on the Publications cards that would take
>you to the appropriate card (i.e. the card of the same name) in the
>Abstracts stack. I tried the following:
>
>	get the name of this card
>	go to it in stack "abstracts"
>
>Getting the name of the card sets `it' to, for example, 'card "r22a"'.
>I was then hoping the second line would get instantiated to
>
>	go to card "r22a" in stack "abstracts"
>
>But that doesn't seem to be the case. I don't get an error message; 
>nothing at all happens.

There are at least three ways to solve this problem.

First, some of what was said isn't true.  If you have this handler in a
button --

on mouseUp
  get the name of this card
  go to it of stack "abstracts"
end mouseUp

-- you will get an alert box that says "Can't understand arguments to
command go".  Note also that 'go to card "XXX" in stack "YYY"' is bad syntax;
it has to be 'card "XXX" of stack "YYY"'. (OF, not IN, if that's too
subtle for you).

Here's solution number one (the easiest):

on mouseUp
  get the short name of this card
  go to cd it of "abstracts"
end mouseUp

Solutions two and three use the "do" command:

on mouseUp
  get the name of this card
  do "go to " & it & "of " & quote & "abstracts" & quote
end mouseUp

on mouseUp
  do "go to " & the name of this card & " of " & quote & "abstracts" & quote
end mouseUp

Solution three is simply a faster version of solution two.

The "do" command will often help you out of sticky situations like this
in which you want what is contained in a variable to be used in a
HyperCard command.



--
Conrad Halling
chh9@midway.uchicago.edu