Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!apple!jdevoto
From: jdevoto@Apple.COM (Jeanne A. E. DeVoto)
Newsgroups: comp.sys.mac.hypercard
Subject: Re: HT & Data structures
Message-ID: <39336@apple.Apple.COM>
Date: 9 Mar 90 05:42:54 GMT
References: <1779@loria.crin.fr>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 31

In article <1779@loria.crin.fr> tenachi@loria.crin.fr writes:
> [...]              I have a question concerning data structures
>in HyperTalk. I wondred if we have the ability to handle non simple data types
>such as arraies, records, pointers..  like in classic languages. Until now I 
>haven't found something dealing with this in the documentation.

Variables in HyperTalk are untyped, so there is not e.g. an array type
as such. However, you can do most (if not all) of the work of records
and (simple) arrays by using chunk expressions (word, line, item, character)
within a variable to structure your data.

For instance, suppose you wish to create a record consisting of the
name, ID, and number of a card. This can be done by storing the name in
line 1 of your variable, the ID in line 2, and the number in line 3. The
values are accessed directly (e.g. "get line 3 of myVariable").

Arrays can be created in similar fashion. Suppose you want a two-dimensional
array: one simple way to accomplish this is to use item number as one
index and line number as the other. To access the [4,7]th item of the
array, you would use the chunk expression "item 4 of line 7 of myArray".

The main limitation I find is that the data can't contain the characters
used as delimiters; if you're using items as array elements, your data
can't contain commas, for instance.
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