World: r3wp

Isn't RUN already a native function ?

Thank you Paul.  Perfect.

Yes, RUN is native, but you can redefine it, if you like.

Yes it is but I don't believe it is of any use.

It is not in r3, alpha 35

I think it was supposed to be a winexecute type of function.

ok, it's clearer now.

I think RUN is extensively used in IOS, but I can't be certain.

Try

source does


and you see, DOES simply makes a function. So instead of using DOES, 
you could also have written:

run: func [] [do %script.r]

, but of course DOES is easier and shorter in this case.

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