World: r3wp

I guess, it's more precise to say, that the decimal! datatype has 
15.95 decimal digits of precision.

 - the most precise is to say, that it has (usually) 53 binary digits 
 of precision. That can be "transformed" to 15.95, but such a "transformation" 
 is quite uniformative, since it ignores some important facts

Fact #1: the representation is binary, and it cannot represent exactly 
even the numbers representable using just one decimal digit

Fact#2: 16-digit decimal numbers cannot be used to represent "exactly 
enough" the IEEE754 binary numbers

(to not confuse the reader, I should have used "precisely enough" 
instead of "exactly enough" in the above fact#2 statement)

why is , not valid word?

>> type? '.
== word!
>> type? ', 
** Syntax Error: Invalid word -- ',
** Near: (line 1) type? ',

Assumably because the opinion was/is, that commas make programs less 
readable. I see no other reason.

I see it absolutely cruicial that there aren't commas between elements 
[ 1 2 3 ] NOT [ 1, 2, 3 ].. but this has nothing to do why , couldn't 
be a valid word of a dialect for example if . ` (for example) are 
IMHO

(I suspect it's used somewhere, but I don't see it .. like % or $ 
is not a valid word since they are part of file / money format ( 
not that parser couldn't be made a little smarter and still allow 
it))

Good question... I was asking as well long time ago http://www.rebol.org/ml-display-message.r?m=rmlDRXJ

Geomol, you are the winner! That is the official reason. Plus, ,0 
is the same as 0.0 since , can be used as a decimal separator.

so any program that has , anywhere is ugly so we ban them.. it's 
no use in complaining, but that doesn't make sense to me.

now my dialect that consumes sql has dots instead of commas [ select 
user.id . user.* from user where id = #myid and name = #name ] .. 
I will surviwe but I will hardly impress any geeks to rebol with 
it as I otherwise could :)

Oldes, I'm on linux where I can't copy poaste that url from altme 
or click it (I don't know why linux doesn't fix dual copy paste and 
istead focuses of various fancy stuff)

So I will reply later when I can

If comma is allowed as word, decision has to be made, what to do 
with things like ,0 as Brian point out. Either anything starting 
with a comma should be words (easy to implement, but might give unpredicted 
result to users trying to writing decimals starting with a comma) 
or a special rule should be made, so it's a decimal, if the comma 
is only followed by digits, else it's a word (harder to implement).

You also need to handle things like:
,000'000e+4
which is simple 0.0 today.

To me, not having comma is a problem in that certain types of data 
become much harder to load.

This is also strange:
b: to-block ";"
length? b
== 0

even:
b: to-block ";;;;;;;"

I think these issues are related to parse, as coma and semicolon 
are default separater for parse.

actually not strange, since to-block converts the string into REBOL 
data, so it's interpreted as an inline comment. I think the behavior 
is correct.

I see, that's correct. I missed that semicolon is for commenting.

TO-BLOCK can be seen as a cheap version of LOAD, AFAIK.

Much cheaper on R3 than R2 - LOAD does a lot of work. Note that TO-BLOCK 
doesn't bind any words in the resulting block, which can come in 
handy sometimes.

thanks, I would I ask what is the difference :)

TO BLOCK! is much safer on untrusted data as well.

what is risk if I use load?

The comma being disallowed as a word does mean you can't use it literally 
i true dialects, but that doesn't prevent you from writing a DSL 
and using string parsing. There have to be lines drawn somewhere.

LOAD used to evaluate headers aggressively, though I don't think 
it does any more under R2. I'm not sure about R3, but I imagine Brian 
has made sure that's safe.

Janko: If you right-click the URL, it says "Copied to clipboard" 
- it means the X clipboard, which you paste from in Linux by using 
middle-click

Izkata: wow .. it works! :)

Oldes: I read the discussion on mailing list. Obviously I agree with 
you (in fact our reasoning is like copied:)

Gabriele interestingly subverted your reasoning by "you can't expect 
REBOL to be able to parse into REBOL values any syntax", but that 
is not the reasoning here :) . Reasoning is simple why rebol isn't 
more consistent and

(pressed the submit by accident).. reasoning is:

If consistency good?

if . is word why isn't ,?
you mentioned that it's because:
>> ,012
== 0.012

but that fails since this also works :)
>> .012
== 0.012

but I know there are more prominent things to change/fix (if any 
will get fixed at all) that I don't realistically expect anything 
changed about this in near future (but that sql dialect would be 
much cooler if it werent for , exception)

index.html is a useful word, index,html is not.

there has to be a place where you draw the line... will you ask for 
$ next? what about #? What about ' ? or : ? or even ; ?

some characters are reserved for a reason. if you're parsing another 
language, use string parsing. LOAD is supposed to parse REBOL, not 
other languages.

' can be used in words like:

>> can't: 42
== 42
>> can't
== 42

Some would argue, comma is kinda the same.

there is a behaviour difference for LAST function on blocks and lists:
>> b: next next [1 2]
>> last b
** Script Error: Out of range or past end  ;which is ok

>> a: next next make list! [1 2]
>> last a
== 2

But it is not same for FIRST
>> first a ;(or first b)
** Script Error: Out of range or past end ;same for both.

>> a
== make list! []
>> last? a
== false

I'd say its a bug with the list! datatype.

I guess so, because reverse is changing the internal position also:
>> a: make list! [1 2 3]
== make list! [1 2 3]
>> reverse a
== make list! [3 2 1]
>> a
== make list! [1]

it goes to last item in the list. But it doesn't work like that for 
block! values.
>> b: make block! [1 2 3]
== [1 2 3]
>> reverse b
== [3 2 1]
>> b
== [3 2 1]

There is a bug report on Rambo for reverse on list!
http://www.rebol.net/cgi-bin/rambo.r?id=4420&

Geomol, right, so, should we also allow # inside a word? Why not 
allow even [ then?


You have to draw a line somewhere, both to simplify the parser, and 
so that the language is readable. The , has a special meaning in 
basically every language, so it's hard to know what the consequences 
of allowing , would be, even assuming the parser is not affected 
by it.

ie. imagine having:

    f (a,b + c,d)

I suspect that'd confuse the hell out of most people.

You could trivially change the parser in Topaz to allow [ and ] inside 
words, and then write something like:

   a[b c]d


but, is that a good thing? So, what's the actual purpose of allowing 
a,b to be a word? So far, the only purpose has been "to parse other 
languages as if they were REBOL". That's not a good purpose, because 
they are *not* REBOL. If you need to parse other syntax, you need 
string parsing. block parsing is for REBOL dialects.


The only sensible reason I can imagine for , to be a word would be 
to use it as an operator so that:

    a , b

means

   also a b


but that has the same readability problems of using . as a "end of 
command marker" in dialects. a nice idea in abstract, but terrible 
in practice.