World: r4wp

Hey all, I'm having such a good time learning again!


I've got some code to generate a print ruler, but I think it could 
be cleaned up a lot more.   

If some of you have a quick moment, could you take a quick look and 
advise me on how to shorten this code.

ruler1: copy ruler2: ""
idx: 0
loop 110 [
	idx: idx + 1
	append ruler1 "_"
	append ruler2 last-digit: last to-string idx
	if last-digit = #"5" [
		clear back tail ruler1
		append ruler1 "+"
		]	
	if last-digit = #"0" [
		either idx < 99 [clear back back tail ruler1]
			[clear back back back tail ruler1]
		append ruler1 to-string idx
		]
	]
replace/all ruler2 "0" "_"
print ruler1
print ruler2



____+___10____+___20____+___30____+___40____+___50____+___60____+___70____+___80____+___90____+__100____+__110

123456789_123456789_123456789_123456789_123456789_ 123456789_123456789_ 
123456789_123456789_ 123456789_123456789_

Try ++ idx instead of idx: idx + 1

I don't like the BACK BACK ... etc, depening upon the length of IDX 
which is what I want to print out 

Can I do something like LENGTH? IDX and use that number to "back 
up the series"?

I'll give ++ idx a try

copy/part tail form idx -1 will give you the last number

shouldn't use mutually exclusive serial if statements

You mean instead of LAST-DIGIT: LAST TO-STRING IDX

yes

Should I use FIND instead?

How can I use the LENGTH? of IDX as a way to CLEAR those last positions.


ie IDX is 110, length is 3 then clear the last 3 characters from 
the ruler1 series and replace with to-string idx

try ? 

clear skip tail series -3

Thanks Graham,


I'm getting an error with ++ idx,  help ++ indicates incrementing 
a 'word, but I'm not understaning it
I'll try your suggestions

>> idx: 1
== 1
>> ++ idx
== 1
>> idx
== 2

:-D   Oh my gosh, i couldn't get copy/part tail form idx - 1 working 
because I thought it was IDX subtract 1.  Ooops, you meant -1 as 
part of copy/part!!!!

>> help copy
USAGE:
    COPY value /part range /deep


So, copy/part takes two parameters:  (1) the start index, and (2) 
the range


If you rewrite the copy/part like I did below, it is much easier 
to see how it is split up:

copy/part
	tail form idx	;parameter 1
	-1		;parameter 2

I'm not saying to use that format for writing your scripts, but as 
a visual aide, it may help.  Also, you could make it kind of lisp-y 
like this:

copy/part (tail form idx) (-1)

Yes, thank you Bo,  I like the lisp-y version!!!

I sometimes do that when I am trying to debug a lot of nested statements, 
because if you use parens, Rebol will let you know that it didn't 
receive something it was expecting instead of just pulling the output 
from the next nested statement.

I've found that it is very easy to nest inside of statements, but 
hard to remember what goes where!!!    I like your suggestion!  :-D

Actually, the first method I posted above is easier to understand 
for a lot of nested statements.  Compare this real line of script 
from one of my programs.

The way I normally write it:

browse probe rejoin copy [http://www.respectech.com/log/show-invoice.cgi?user=
username "&pass=" password "&submit=" replace/all client "&" "%26" 
"&invno=" invnum either amtdue [rejoin ["&notice=1&amtdue=" to-decimal 
amtdue "&daysdue=" daysdue]][copy ""]]

Lisp-y:

browse (probe (rejoin (copy [http://www.respectech.com/log/show-invoice.cgi?user=
username "&pass=" password "&submit=" (replace/all (client) ("&") 
("%26")) "&invno=" invnum (either amtdue [rejoin ["&notice=1&amtdue=" 
(to-decimal amtdue) "&daysdue=" daysdue]][copy ""])])))


Heirarchical (takes a lot more space, but is easier to follow -- 
however, doesn't have the parameter enforcement of parens):
browse
	probe
		rejoin
			copy
				[
					http://www.respectech.com/log/show-invoice.cgi?user=
					username
					"&pass="
					password
					"&submit="
					replace/all
						client
						"&"
						"%26"
					"&invno="
					invnum
					either
						amtdue
						[
							rejoin
								[
									"&notice=1&amtdue="
									to-decimal
										amtdue
									"&daysdue="
									daysdue
								]
						]
						[
							copy
								""
						]
				]

I'm glad we don't have to use the Lisp method or the heirarchical 
method, but it is nice that we can, especially when we are starting 
out.  I usually only use the heirarchical method when I am trying 
to understand and visualize someone else's really complex scripting. 
 I'll use the Lisp method when I am getting an error that I have 
narrowed down to a small snippet of code, and I can't figure out 
why the error is occurring.  I also throw in a lot of 'probe statements 
to see what's really going on.

Patrick,

    clear back tail ruler1
    append ruler1 "+"

actually is

    change back tail ruler1 #"+"

Similarly,

		either idx < 99 [clear back back tail ruler1]
			[clear back back back tail ruler1]
		append ruler1 to-string idx

can be written as

		change skip either idx < 99 [-2] [-3] to-string idx

err, I lost a part of the expression:


    change skip tail ruler1 either idx < 99 [-2] [-3] to-string idx

Patrick, rather than building up the strings bit by bit, consider 
how you might do it if you think of them as a buffer you're modifying. 
e.g., start with something like this:

ruler1: copy ""
insert/dup ruler1 "_" 110
forskip ruler1 5 [change skip ruler1 -1 "+"]

or this

ruler1: head insert/dup copy "" "____+" 22

Sometimes things aren't clearer when you reduce them, but sometimes 
it can work well.

Thank you Bo, Ladislav, and Gregg  -- I'll use all your suggestions 
:-)

Thanks to all that helped. Learning all the time.  I think I have 
the code pretty tight now!  A lot better than my first attempt.  
Final solution:

ruler-len: 80

ruler-1: head insert/dup (copy "") "----+----."	to-integer (ruler-len 
+ 9 / 10)
ruler-1: head clear (skip ruler-1 ruler-len)		; trim excess
r1: skip head ruler-1 9				; adv to pos 10
forskip r1 10 [	adj: ((length? idx: to-string (index? r1)) - 1)
				change skip r1 (-1 * adj) idx		]
ruler-1: head r1					; r1 is at tail

ruler-2: head insert/dup (copy "") "123456789." to-integer (ruler-len 
+ 9 / 10)
ruler-2: head clear (skip ruler-2 ruler-len)	; trim excess
print-ruler:	does [print ruler-1 print ruler-2]

My notes:


* it is absolutely unnecessary to set RULER-1 three times to the 
same value thus, I normally do:

    ruler-1: copy ""

    insert/dup ruler-1 "----+----." to-integer (ruler-len + 9 / 10)
    clear (skip ruler-1 ruler-len)		; trim excess
    ....
    ; for the same reason it is unnecessary to do:
    ; ruler-1: head r1

... and for the same reason I would do

    r1: skip ruler-1 9 ; HEAD unnecessary

The same note applies to RULER-2

When Carl had me write my first Rebol script, his goal was to see 
if I understood how scripting in Rebol is different than most other 
languages.  One of the helpful things he told me was that if you 
see patterns in your scripts, then you are likely not scripting as 
efficiently as possible.

Bo, that's a great quote.

LOL, I was just posting a rant on FB that can be summed up as "if 
you do it over and over again, make a BLOODY shortcut".

Ladislav,  Excellent notes!!!  For whatever reason, (old coding habits 
I guess) I started with defining the object RULER-1 and then manipulating 
it.  I now see what you are saying about  using the INSERT/DUP.  
As to notes about HEAD, I realize now that I confused INSERT and 
APPEND, (thinking it inserts at tail, when it doesn't.


I welcome any and all comments to help me get out of my paradigm!!

As to notes about HEAD, I realize now that I confused INSERT and 
APPEND

 - APPEND used in a similar way as above would not need HEAD either

Neither INSERT nor APPEND modify the index attribute of their argument 
(the index attribute of series is immutable, in fact)

Having a series with index 1 (the head has this index), neither INSERT 
nor APPEND can change the index of the series. What they do is something 
else - they return a series with a different index.

To illustrate this further, let's consider a trivial example:

    a: 1
    b: 2

    add a b ; == 2


You can examine A and B now and see that the ADD function did not 
change A or B, but it returned 2 (another value). Similarly, INSERT 
does modify the argument series, but not its index, however it returns 
a series with a different index.

Is this clear?

Your example should be "== 3" I guess?

:-)

(best of us can be wrong sometimes. Just to LOL, no pun intended)

>> add: :multiply
>> a: 1
== 1
>> b: 2
== 2
>> add a b
== 2

You can always find a solution :-)

/LAST refinement doesn't return the last match when used with /REVERSE 
refinement. Is that a known issue?

>> FIND/reverse/last tail "aoboco" "o"
== "o"
>> FIND/reverse tail "aoboco" "o"
== "o"

>> FIND "aoboco" "o"
== "oboco"
>> FIND/last "aoboco" "o"
== "o"

Hello, someone needs Sublime Text 2 editor  syntax highlight file, 
see http://rebol.informe.com/forum/rebol-2-f8/sublime-text-2-t59.html
Do you know where he may find it?

find/reverse and find/last are somewhat identical but not from the 
same point of start. So you have to use one XOR the other.

Endo, what result do you expect for

  FIND/reverse/last tail "aoboco" "o"

?

Your example should be 

== 3" I guess?" - actually, I had a: 1 and b: 1 originally, and I 
somehow "managed" to change B to 2 :-(