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Author: Anton ErtlAnton Ertl Date: Aug 3, 2007 11:07
Problem
It is often useful to write numbers in other than the current BASE.
Changing BASE to do this is often inconvenient and has lead to
hard-to-find errors.
Solution
The Forth text interpreter should accept numbers like the following ones:
#-12346789. \ decimal double
$-1234cDeF. \ hex double
%%-10101010. \ binary double
'a' \ equivalent to char a or [char] a
(and of course without "." for single-cell and without - for positive
and unsigned numbers; the text interpreter only has to accept
double-cell numbers if the double-cell wordset is present).
Typical usage:
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Date: Aug 3, 2007 13:11
> Problem
>
> It is often useful to write numbers in other than the current BASE.
> Changing BASE to do this is often inconvenient and has lead to
> hard-to-find errors.
First of all, I would suggest to use & as a "prefix" for octal
numbers.
Second: I dont understand, why it has to be a prefix. I could
perfectly imagine to have multiple such "prefixes" to construct
numbers - eg. to contruct numbers with mixed bases. A number converter
would then (temporarily) change the base at the point where the
"prefix" occurs.
Third: To simplify things, the minus-sign should simply flag that the
result is negative (as . (dot) does with doubles), as long as there
are no digits other than 0 (zero). That means an implementation has
simply to check if temporary convert result is zero and then to accept
the minus.
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Date: Aug 3, 2007 13:16
> 12-34
means -1234
-Helmar
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Author: Alex McDonaldAlex McDonald Date: Aug 3, 2007 13:56
> Problem
>
> It is often useful to write numbers in other than the current BASE.
> Changing BASE to do this is often inconvenient and has lead to
> hard-to-find errors.
>
> Solution
>
> The Forth text interpreter should accept numbers like the following ones:
>
> #-12346789. \ decimal double
> $-1234cDeF. \ hex double
> %%-10101010. \ binary double
> 'a' \ equivalent to char a or [char] a
>
> (and of course without "." for single-cell and without - for positive
> and unsigned numbers; the text interpreter only has to accept
> double-cell numbers if the double-cell wordset is present). ...
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Author: Alex McDonaldAlex McDonald Date: Aug 3, 2007 14:05
>> Problem
>
>> It is often useful to write numbers in other than the current BASE.
>> Changing BASE to do this is often inconvenient and has lead to
>> hard-to-find errors.
>
> First of all, I would suggest to use & as a "prefix" for octal
> numbers.
>
> Second: I dont understand, why it has to be a prefix. I could
> perfectly imagine to have multiple such "prefixes" to construct
> numbers - eg. to contruct numbers with mixed bases. A number converter
> would then (temporarily) change the base at the point where the
> "prefix" occurs.
>
> Third: To simplify things, the minus-sign should simply flag that the ...
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Date: Aug 3, 2007 14:11
On Aug 3, 11:05 pm, Alex McDonald rivadpm.com> wrote:
> Ouch to 12-43. O-uch ou-ch ouc-h, that hurts, even in base36.
Yes, that's why I did not want to write it. I forgot to remove this
example. That's also why I wrote the converter should check for zero.
I know that you would say "ouch" ;)
> And 1- is not a number.
: 6 ." six" ;
and 6 is no number.
-Helmar
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Author: Alex McDonaldAlex McDonald Date: Aug 3, 2007 14:18
> On Aug 3, 11:05 pm, Alex McDonald rivadpm.com> wrote:
>>> Ouch to 12-43. O-uch ou-ch ouc-h, that hurts, even in base36.
>
> Yes, that's why I did not want to write it. I forgot to remove this
> example. That's also why I wrote the converter should check for zero.
> I know that you would say "ouch" ;)
>
>> And 1- is not a number.
>
> : 6 ." six" ;
>
> and 6 is no number.
>
> -Helmar
I meant that 1- is defined in the standard; it's not the same as -1.
Allowing 0- would simply serve to confuse.
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Date: Aug 3, 2007 14:25
On Aug 3, 11:18 pm, Alex McDonald rivadpm.com> wrote:> On Aug 3, 10:11 pm, hel...@ gmail.com wrote:
> >> On Aug 3, 11:05 pm, Alex McDonald rivadpm.com> wrote:>
>>> Ouch to 12-43. O-uch ou-ch ouc-h, that hurts, even in base36.
>
>> Yes, that's why I did not want to write it. I forgot to remove this
>> example. That's also why I wrote the converter should check for zero.
>> I know that you would say "ouch" ;)
>
>>> And 1- is not a number.
>
>> : 6 ." six" ;
>
>> and 6 is no number.
>
>> -Helmar
>
> I meant that 1- is defined in the standard; it's not the same as -1. ...
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Date: Aug 3, 2007 14:27
> '-' Of Result @ Negative? @ abort" sign on wrong place"
'-' Of Result @ Negative? @ or abort" ...
(Today's a bug in my keybord ;) )
-Helmar
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Author: Coos HaakCoos Haak Date: Aug 3, 2007 15:11
Op Fri, 03 Aug 2007 13:11:13 -0700 schreef helmwo@ gmail.com:
>> Problem
>>
>> It is often useful to write numbers in other than the current BASE.
>> Changing BASE to do this is often inconvenient and has lead to
>> hard-to-find errors.
>
> First of all, I would suggest to use & as a "prefix" for octal
> numbers.
Why, who's still using octal in this century? I'm perfecty comfortable with
& as an alternative to CHAR or [CHAR]
> Second: I dont understand, why it has to be a prefix. I could
> perfectly imagine to have multiple such "prefixes" to construct
> numbers - eg. to contruct numbers with mixed bases. A number converter
> would then (temporarily) change the base at the point where the
> "prefix" occurs.
Too complicated, and confusing
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