AltME groups homeHelpJoin REBOL3 world
  Find AltME posts   Help

Recent posts

Worlds:r4wpr3wp
AccessibilityAbout / FAQ
Member's loungeContact/FeedbackOther REBOL links
Membership:
member name

password

Remember?

Not a member? Please join
29-Jun 14:34 UTC
[0.07] 17.717k
r3wp [groups: 83 posts: 189283]
  • Home
  • Script library
  • AltME Archive
  • Mailing list
  • Articles Index
  • Site search
 

World: r3wp

Join the discussions in the REBOL3 world...

[Red] Red language group

older
newer		first
last
Steeve
29-Dec-2011
[4111]
for SWITCH I can see the need (computing labels in array to support 
indirect threading ) a speed issue.

But why do you need to implement CASE in red/system, it's only a 
sequence of if/else statements ?
Dockimbel
29-Dec-2011
[4112x2]
(answered just above :-))

CASE helps "flatten" the nested IF or EITHER constructions.
Steeve
29-Dec-2011
[4114x2]
except than the if-else statement (the c one) is usually mis-used.
It doesn't need to be nested to work.
if .... else if .... else if .... else if .... else

FLAAAAT :-)
BrianH
29-Dec-2011
[4116x2]
In REBOL we tend to use CASE instead of EITHER because CASE is faster 
when there are more than 2 tests. Flat is just a side benefit. Of 
course, an optimizing compiler could change the resulting code from 
one to another when it's appropriate, just like most modern C/C++ 
compilers do.

I hope you have a CASE/all option. We used the CASE/all style in 
the R3 module system code to great benefit, mostly in maintainability 
but also in speed, when compared to the nested IF and EITHER code 
it replaced. It enabled us to add features and simplify code at the 
same time.
Steeve
29-Dec-2011
[4118x3]
I wasn"t against CASE implementation in Red.

I was asking if it was the right place to have it in Red/system as 
a core function instead of as a latter compiled mezz.

but maybe a mixed the things between Red/system and the other layers

To be clear about that. Doc can you confirm that the mezz constructed 
with Red will be also compiled ?
BrianH
29-Dec-2011
[4121]
IF, UNLESS, EITHER, CASE and SWITCH all make sense to compile in 
a compiled language because they all translate to branches and/or 
index lookups in the generated code, and optimizing that would need 
some decent compiler support. If anything, CASE is the most general 
(the others can all be implemented with CASE), and would benefit 
the most from optimization.
Pekr
29-Dec-2011
[4122]
what is make-float-auto-test.r? Do we have floats supported or so? 
:-)
Kaj
29-Dec-2011
[4123]
Nice catch :-)
Pekr
29-Dec-2011
[4124x2]
I think we don't, so maybe just a preparation for what is about to 
come one day :-) IIRC Doc was investigating, what would it take to 
get floats supported by RED/System :-)

re Documentation - Content is missing 13.3.7 CASE
Kaj
29-Dec-2011
[4126]
See above
Pekr
29-Dec-2011
[4127]
Kaj - I mean - CASE is described, but it is not part of the basic 
points ...
Dockimbel
29-Dec-2011
[4128x2]
Pekr: the ... just indicates that the <condition> [<body>] pattern 
can be repeated.

make-float-auto-test.r: just some preliminary tests from Peter, nothing 
has been implemented yet wrt float.
Kaj
29-Dec-2011
[4130]
Isn't the TOC autogenerated by MakeDoc?
Dockimbel
29-Dec-2011
[4131x4]
It is.

I don't see missing content in online doc??

Mezz in Red: yes, they will be compiled.

CASE in Red/System and CASE in Red are two different functions. The 
Red version may or may not rely on the Red/System one.
Pekr
29-Dec-2011
[4135]
my mistake. TOC does not containt full details. CASE is 13.3.7, but 
TOC uses two levels - 13.3, so it is OK ...
Dockimbel
29-Dec-2011
[4136]
Right, two levels is already quite long, not sure I should extend 
it more?
Kaj
29-Dec-2011
[4137]
I do agree that it is a bit hard to find specific things in the current 
manual
Dockimbel
29-Dec-2011
[4138x5]
CASE/all: could be added to Red/System (would be called case-all), 
but as I'm personally not a great user of CASE/all, I'll wait for 
other users to ask for it. ;-)

Specification: I agree that find the native function is not handy, 
I could remove the "API Reference" level to make it easier to find 
from TOC.

find => finding

BTW, the "manual" is supposed to be a (more or less formal) specification 
of the language, but as I didn't have time to write a separate user 
manual, it now tends to serve for both uses.

New handier (I hope) chapters layout: http://static.red-lang.org/red-system-specs.html
Kaj
29-Dec-2011
[4143]
Looks good
Henrik
29-Dec-2011
[4144x2]
What is returned, when no case passes?

I mean, whether that is necessary to have in the specs.
Dockimbel
29-Dec-2011
[4146]
In such case, result is undefined. If you need a return value, it's 
up to you to provide a "catch all" ending rule that never fail.
BrianH
29-Dec-2011
[4147]
Out of curiosity, Doc, not criticism, why did you pick the 3-clause 
BSD license instead of the 2-clause BSD?
Dockimbel
30-Dec-2011
[4148x2]
Just because it looked good to me when I had to pick one. But since 
then, Andreas made me realize that it can be problematic for derivated 
works because of the "prior written permission" part. That is why 
the current Red runtime source code is licensed under the Boost License. 
I think I'll just re-license the whole source base under BSD 2-clause 
when I'll find some time for that.

derivated => derivative (hard remembering this one)
Andreas
30-Dec-2011
[4150x3]
The reason for using the Boost License for the runtime was clause 
two: "Redistributions in binary form must reproduce the above copyright 
notice, ..." .

A Red/System-produced binary linked with the Red/System runtime arguably 
is a redistribution of the Red/System runtime in binary form.

The Boost Software License is even more permissive in this regard, 
and should therefore make sure that Red/System-produced binaries 
can be distributed without any restriction.
Dockimbel
30-Dec-2011
[4153]
Forgot about that, right! So not even the 2-clause BSD is permissive 
enough?
Andreas
30-Dec-2011
[4154]
Nope, I'd suggest sticking with the BSL for the runtime.
BrianH
30-Dec-2011
[4155x2]
The heck with it, go with the WTFPL :)

Andreas, you forgot the "in the documentation and/or other materials 
provided with the distribution" - it's iffy as to whether you need 
to provide them in the binary itself. Still, the BSL looks good. 
I should consider it for R2/Forward and my R3 mezzanine work, since 
the MIT license has the same restriction as the second clause of 
BSD-2.
Dockimbel
30-Dec-2011
[4157x4]
WTFPL looks good. ;-)

SWITCH native implemented in Red/System, here is an example of supported 
features:

a: 5
ret: switch a [
	0 	[print "0" 0]
	1 #"^E" [print "1" 1]
	2 6 	[print "2" 2]
	3 	[print "3" 3]
	default [print "no match" -1]
]

print [lf ret lf]

* Mutiple values allowed (even mixing integer! and byte!)
* Returns last value
* Optional default clause

Also the SWITCH argument can be any valid Red/System expression.
older
newer		first
last