World: r3wp

And now you're at it, try

source func

and see how similar to DOES it is.

And the last one in this group of function-defining functions, try

? has
source has

I use FUNC, DOES and HAS a lot in my scripts.

Good to know -- Thank you

welcome

A little tutorial on HAS, functions and objects. Let's say, I wanted 
to make a function with a local variable, that works like a counter, 
so 1 is added to it every time, I call my function. This doesn't 
work:

>> f: has [a] [a: 0 a: a + 1]
>> f
== 1
>> f
== 1


because a has to be defined (given a value and by that a datatype), 
before I can use it, and I need to use it, when I add 1. So I can 
use an object:

>> o: make object! [a: 0 f: does [a: a + 1]]
>> o/f
== 1
>> o/f
== 2


But there is a trick to do the same thing with HAS and without making 
an object:

>> f: has [a] [a: [0] a/1: a/1 + 1]
>> f
== 1
>> f
== 2


The thing is, that a is giving a block with zero inside the first 
time. The second time, I call f, a is just the same block (part of 
memory), and the value inside isn't touched (it is 1 now), so it 
works. I can see the block inside my function with:

>> source f
f: func [/local a][a: [2] a/1: a/1 + 1]


and we see, a is a block with 2 inside, because I've called my function 
2 times.

If you used a: [0], doesn't this assign a zero to the block for a?

I gotta play around with that

a: [0] simply mean, a become this block with zero inside, if a isn't 
already this block. If a already is this same block, this same part 
of memory, it has no effect. To always make a block with zero inside, 
you need to use COPY or REDUCE.

I was often confused by this, I remember.

When you get used to it, it's pretty smart.

This is only within functions. If you write a: [0] at the console 
prompt, a become a new block with zero inside (you typed a new block, 
so it isn't the same, and it kinda makes sense). :-)

>> print abc
** Script Error: abc has no value
Ok, no problem I understand

>> print <abc>
<abc>
Why does this work ?

abc is seen as a word, and it doens't have a value. <abc> is a tag! 
datatype, like "abc" is a string datatype:
>> type? <abc>
== tag!

and it also is a series, like strings are series:
>> second <abc>
== #"b"

Geomol: I wasn't aware there was a tag type !

kib2:

build-tag [img src dot.gif]

kib2, to see all types:

? datatype!

Really useful : thanks !

I've forgot, what a symbol! datatype is!?

s there any 'Challenge' channel for submitting a problem ?

Puzzles

Geomol: ok, thanks.

And answers go to Puzzle Answers

And people expect rewards. ;-)

All my gratitude !

I already solved it, but it's not nice (and maybe faulty)

Another question:  How do you setup Rebol code to be performed when 
a button is pressed?

Lets say I want a VID to show a list of websites to open to, and 
I set the default to HULU.
I have the following to setup the correct url:
 k-prefix:	[http://www.]
k-suffix:	[.com]
txt-site:	[hulu]
url-site:	to-url ajoin [k-prefix txt-site k-suffix]

OK, that works when I do a browse url-site

But when I put it after a button like this:
    group [

        button "Open"	browse url-site    <-- this code works only if it is 
        done before the VIEW  
        button "Reset" 	reset 
        button "Cancel"	close

I tried to replace the browse url-site with
browse to-url ajoin [k-prefix txt-site k-suffix]   to no avail.

Is there a way to "predefine" the code above the VIEW so that when 
the button is pressed, it will perform the desired task like

button "Open"    format-and-browse-site    <-- where this has been 
set to do the url-site assignment and browse funtions?

I'm guessing this may have something to do with the DO , DOES, REDUCE, 
or other such functions

Is this R2 or R3?

R3

button "Open" do [browse url-site]

I think.

Hi Henrik,

This issue is not when to do the browse, that works, but when the 
url-site is properly assigned.

I'm not sure what you mean.

Try this:
REBOL []
; Assignments ------------------------------------
k-prefix:	[http://www.]
k-suffix:	[.com]
txt-site:	[hulu]
url-site:	to-url ajoin [k-prefix txt-site k-suffix]

; Main-procedure ---------------------------------
load-gui
view [
    title "WebSite Selector" 
    text "Please choose a website you would like to open" 
    panel 2 [
        label "URL:" 
        txt-site: field "Hulu"
        label "WebSites:" 
        area 
    ] 
    group [
        button "Open"	browse url-site 
        button "Reset" 	reset 
        button "Cancel"	close 
]	]

When you press Open, it will open the browser to Hulu.com

But I need to modify the code so that I can change the HULU to another 
site like GOOGLE

So, I need to replace button "Open" browse url-site with something 
that will evaluate the url-site AT THAT TIME, rather than what I 
have it defaulted to

As I said, you need a DO block (I think you missed that). Then you 
create a function to create the URL-SITE url. Then you use that as 
input with BROWSE and that will work.

Thanks Henrik, I'll give it a try

inspiration:

view [group [f: field] group [button do [probe get-face f]]]

Henrik,  I added the following code:

    eval-url-site:	does [to-url ajoin [k-prefix txt-site k-suffix]]
and then after the button "open" i have:
    button "Open"	browse eval-url-site

I get a ***GUI Error: Cannot parse the GUI dialect

But if I type browse eval-url-site at the console, it works -- What 
am I missing?

Patrick, it is still incorrect WRT to the DO block. Try reading my 
inspiration line.

you must DO right at the button.

Ohhhh, I missed that

How to solve such problem ?
It seems like input-file is evaluated with none as infile value.

REBOL []

container: make object! [
    infile: none
    input-file: read join infile ".txt"
]

c: make container [infile: %rme/test]