Re: [colorforth] Question about displaying text

["Ray St. Marie" <ray.stmarie@xxxxxxxxx>]

Hi John,
Ray here...
Well done, this.

On 12/26/06, John Drake <jmdrake_98@xxxxxxxxx> wrote:
> Hello all,
>
> I've made some progess on the Primary ColorForth
> tutorial.
...

> http://www.quartus.net/cgi-bin/twiki/view/Main/PrimaryColorForthEditor
>
> I also added the examples from chapter 1 of
> Starting Forth that I had documented on my
> blog.
>
> http://www.quartus.net/cgi-bin/twiki/view/Main/PrimaryColorForthGettingStarted

Great job here. Keep it up. I'll be helping soon.

> Now for my question.  I've actually finished
> the rest of the example from chapter 1.  But
> I'm not 100% satisfied with the results.
>
> This is what I have so far.  I know how to
> display a packed word that's on the stack.
>
> : type fffffff0 and unpack if emit type ; then
> drop drop ;
>
> This recursively upacks a charecter and displays.
> If the charecter is 0 then we're at the end of
> the word and "type" stops.  So if "hello" was
> at the top of block 20 then
>
> : ok show text 20 block type keyboard ;
>
> would create a word to display "hello" at the
> top of the screen.
>
> I also figured out a way to use "string
> variables".  Magenta variables are basically
> pointers to areas of memory inside of blocks.
> So if you put a magenta variable address on
> the stack and add 1 to it you'll have a
> pointer to the packed source code that comes
> after the variable.  So I create magenta
> variables and then put the string I want
> directly after the variables in the form
> of comments.
>
> var s 0 ( hello )
>
> Then
>
> : ok show text s 1 + @ type keyboard ;
>
> will also display "hello" on the screen.
>
> Factoring out "1 + @ type" I get:
>
> : stype 1 + @
> : type fffffff0 and unpack if emit type ; then
> drop drop ;
>
> But the problem is, what happens when you have
> longer words?  For example:
>
> var s 0 ( bookends )
>
> If I do:
>
> : ok show text s stype keyboard ;
>
> I get:
>
> booke
>
> Now I can chain words together.  For example
> I created a word "dword" to deal with long
> words like "bookends".
>
> : dword dup stype 1 + stype ;
>
> Then
>
> : ok show text s dword keyboard ;
>
> displays:
>
> bookends
>
> But there HAS to be a better way.  How can
> I get ColorForth to differentiate between
> short words like "hello" that get packed
> into a single 32 bit word and longer words
> like "bookends" that take 2 32 bit words?
>
> Clearly the editor knows how to do this
> because it displays "bookends" just fine.

Okay, this was neat. I don't have much time right
now to test, but I suspect you will find that before
unpacking the 'double-bytecoded-word' you will
need to duplicate the first portion and get it's tag.
A tag of 0 will indicate a second portion, and you
may need to recurse thru all of these 0 tagged
portions, feeding each to your type word.

I'll try to knock something off after work today.

Again, keep the flame burning, your not alone :-)
Ray


> Regards,
>
> John M. Drake
>
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