How can I dynamically display a stream position?

Question

If I create a stream,

str = StringToStream["how can I dynamically display the stream position"];
Read[str, Word]

"how"

then, when I use,

Dynamic[StreamPosition[str]]

The output will not dynamically update the current state of the stream position.

Any ideas?

A workaround, of course Dynamic[Refresh[Streams[], UpdateInterval -> 1]] — Dr. belisarius, Commented Nov 20, 2015 at 20:46
The stream str contains only stream ID and it never changes. You can obtain full stream information with Internal`StreamInformation[str]. Unfortunately, It doesn't solve the problem. — ybeltukov, Commented Nov 20, 2015 at 21:46

Kuba · Accepted Answer · 2015-11-20 21:26:41Z

4

To not prompt Dynamic each second or something, let's create useless variable that will prompt it.

Dynamic[T`r; StreamPosition[str]]
read = (T`r = Read[##]) &;
read[str, Word]

answered Nov 20, 2015 at 21:26

Kuba

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$\begingroup$ Veggy, veggy nice! $\endgroup$
– Dr. belisarius
Commented Nov 20, 2015 at 21:43
$\begingroup$ Well done! could you perhaps explain the mechanics behind these notations? i.e. the " ` " $\endgroup$
– Peter Roberge
Commented Nov 20, 2015 at 23:00
$\begingroup$ @peter I just used T contex to not pollute the default Global` . $\endgroup$
– Kuba
Commented Nov 20, 2015 at 23:29
$\begingroup$ @Kuba cool, thanks $\endgroup$
– Peter Roberge
Commented Nov 20, 2015 at 23:49

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