Re: Mac Open file dialog

[reti@cambridge.apple.com (Kalman Reti)]

At 12:08 AM 4/22/94 +0000, Andrew Begel wrote:
>I have a slight problem. In the docs for (open-file-dialog) it says that 
>you can include a :mac-file-type parameter that will take a 4 char
>string (like "lisp", or "fasl") and restrict the directory entries in the open file dialog to those types. Has anyone ever used this feature? I've tried, 
>and instead of showing "lisp" files (say) it just shows no files except for
>directories. 

You've run afoul of the overloading of the word "type".  On the Mac, each file has two
internal (e.g. only visible using tools like ResEdit) four-character fields, a 'creator' and
a 'type'.  This information is what the finder uses to assign the right icons, launch 
applications when you click on files created by them, etc.  The functions MAC-FILE-TYPE
and MAC-FILE-CREATOR can access these internal types.  Lisp files in MCL have
a type of "TEXT" (and a creator of "CCL2"), whereas fasl files have a type of "FASL"
(and also a creator of "CCL2").

This has absolutely nothing to do with the part of a file name after a period, e.g. ".lisp",
which is sometimes called a "type" by other operating systems. 

You only saw directories because there were presumably no files with the internal
type you specified.

>
>Can anyone tell me the syntax on how to use this command? The docs are wrong in the 
>MCL 2.0 manual.
>
>Thanks
>
>Andy Begel
>MIT Media Lab
>Epistemology and Learning Group
>abegel@media.mit.edu