Re: How to read characters from stdin?

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On Tuesday, May 5th, 2026 at 3:54 PM, Bernd Paysan <[email protected]> wrote=
:

> Am Dienstag, 5. Mai 2026, 17:31:53 Mitteleurop=C3=A4ische Sommerzeit sch=
rieb jlyonm =


> via Gforth discussion and announcements:
> > On Tuesday, May 5th, 2026 at 1:55 AM, Mark J. Reed <[email protected]=
m> =


> wrote:
> > > On Mon, May 4, 2026 at 11:53=E2=80=AFAM jlyonm <jlyonm-g/[email protected]=
m> wrote:
> > > > I wanted to write a simple program that reads input from stdin, an=
d
> > > > writes it out to stdout doing a little translation.> =


> > > Ok, so does your program need to respond to each individual key pres=
s, or
> > > can it read a whole line and then process that all at once?
> > I'm reading one character at a time.
> > =


> > > > At first I thought I could make use of key and key?, but I see the
> > > > documentation indicates this can't be used on stdin.> =


> > > I'm confused - don't those words work exclusively on stdin?
> > =


> > In the Gforth info document, section 2.6 it says, "If you pipe into Gf=
orth,
> > your program should read with `read-file' or `read-line' from `stdin'.
> > `Key' does not recognize the end of input." This is exactly what I am
> > seeing with my little program. It never exits.
> =


> KEY does recognize end of file, but it throws an exception instead of pa=
ssing a =


> flag.
> =


> For that purpose, there is now (in the development snapshot) KEY-IOR, wh=
ich =


> returns a negative value for end of file or other exceptions.
> =


> $ echo "check this" | gforth -e ": test begin key-ior dup 0>=3D while h.=
 repeat =


> drop ; test cr bye"
> $63 $68 $65 $63 $6B $20 $74 $68 $69 $73 $A
> =


> End of file is error code -512 (which translates into =E2=80=9Csuccess=E2=
=80=9D if thrown, as =


> there is no errno assigned to EOF).
>
Thanks for the extra details. I did not know about any of this.

> > > Just use stdin file-eof? ?
> > =


> > Thanks a lot, this is exactly what I needed, and makes it work. How do=
es one
> > find that word? It is not in the info docs, nor can I find it online. =
I
> > wonder what else I am unaware of.
> =


> FILE-EOF? is documented in the current development manual.
> =


> https://net2o.de/gforth/
> =


> Go to the index, search for EOF, and second hit is it.
> =


I am definitely bookmarking this page. I only knew about these pages on Gf=
orth:
https://www.gnu.org/software/gforth/
https://www.complang.tuwien.ac.at/forth/gforth/Docs-html/

> > > > In case it matters, I'm actually running this on a phone running L=
ineage
> > > > OS (ostensibly Android) under termux. I don't think it effects the
> > > > behavior.
> =


> The termux version is likely 0.7.3, and the development documentation ca=
n be =


> significantly ahead of the functions available there.
>
You are correct, termux has Gforth 0.7.3. I should have checked and provid=
ed the
version.

> -- =


> Bernd Paysan
> "If you want it done right, you have to do it yourself"
> net2o id: kQusJzA;7*?t=3Duy@X}1GWr!+0qqp_Cn176t4(dQ*
> https://net2o.de/
> =


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