ftp.cs.arizona.edu/ftp.cs.arizona.edu.tar/ftp.cs.arizona.edu/icon/newsgrp/group92c.txt/000058_icon-group-sender _Wed Nov 4 07:05:19 1992.msg

Internet Message Format | 1993-01-04 | 2KB

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Date: Wed, 4 Nov 92 15:03 MET
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Subject: file scanning
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Richard Goerwitz writes:

>One thing that's worth thinking about is whether string scanning could
>be extended to cover files.  That would solve your problem.  Seems
>like a great idea to me.  Really great.  It's something the Icon Pro-
>ject has been talking about.  Any bright students at the U of Arizona
>looking for class projects :-).  Would take some interesting buffering
>and a lot of fseeks.  But wouldn't it be neat to have scanning usable
>on character streams as well as strings?

This was somewhat surprising to me, because I already do string
scanning on files. I'll explain how, and I'm eager to receive
comments on the proposed method. The method works great on Ultrix,
and MSDOS (386) platforms, so I gather it's kosher Icon. The basic
tric is to use the ! generator twice.

Suppose we just want to print all successive characters in a text file.
The text file is:

<begin file>
The man the woman the
dog bit hit chose to be free.
<end file>

Now one way to scan the entire file (as if it's one string, so
to speak) is this:

procedure main()
  inputfile := open("filename")
  !!inputfile ? while write(move(1))
end

the output is:
The man the woman thedog bit hit chose to be free.

If this looks simple, that's because it is simple, but I wonder:
Is this what is meant by scanning a character stream, or have I
understood the problem wrongly?

Jan P. de Ruiter
Max Planck Institute for Psycholinguistics
[e-mail]