Re: [racket-dev] Character classification
2012/9/4 Pierpaolo Bernardi : > On Tue, Sep 4, 2012 at 3:11 PM, Jens Axel Søgaard > wrote: >> Since the R5RS version of char-numeric? (according to the documentation) >> tests for the ten digits, you can use: >> >> (require (only-in r5rs char-numeric?)) > > Thanks Jens Axel. However, the r5rs version appears to be the same as > the Racket version. I consider that a bug. http://docs.racket-lang.org/r5rs-std/r5rs-Z-H-9.html?q=char-numeric%3F#%_idx_490 "The numeric characters are the ten decimal digits." Note that meaning changed in R6RS: "A character is numeric if it has the Unicode “Numeric” property." So the current Racket behaviour matches R6RS. /Jens Axel Tested with: > > > #lang r5rs > > (define (test) > (let again ((i 0)) > (cond ((< i #xD800) >(let ((c (integer->char i))) > (cond ((char-numeric? c) > (display (list i c)) > (newline))) > (again (+ i 1))) > -- -- Jens Axel Søgaard _ Racket Developers list: http://lists.racket-lang.org/dev
Re: [racket-dev] Character classification
On Tue, Sep 4, 2012 at 5:03 PM, Sam Tobin-Hochstadt wrote: > On Tue, Sep 4, 2012 at 10:57 AM, Pierpaolo Bernardi > wrote: >> >> What is annoying is that char-numeric? and string->number are not compatible. > > `char-numeric?` and `string->number` would not be "compatible" in the > sense you're thinking of, even with the change you mention. > > For example: > > -> (string->number "+i") > 0+1i > -> (string->number "1#e4") > 10.0 They would be compatible in the other direction. A string composed of char-numeric? chars would be accepted by string->number. In short, my-char-numeric? is a function that is useful, has been in scheme since the stone age, and nowadays I have to write it myself, and remember to not use char-numeric?, since it is never what I need (and when I'll need the char-numeric? functionality I can get it with char-general-category). (Sorry about the previous duplicate messages. I don't know what's causing them) P. _ Racket Developers list: http://lists.racket-lang.org/dev
Re: [racket-dev] Character classification
On Tue, Sep 4, 2012 at 10:57 AM, Pierpaolo Bernardi wrote: > > What is annoying is that char-numeric? and string->number are not compatible. `char-numeric?` and `string->number` would not be "compatible" in the sense you're thinking of, even with the change you mention. For example: -> (string->number "+i") 0+1i -> (string->number "1#e4") 10.0 -- sam th sa...@ccs.neu.edu _ Racket Developers list: http://lists.racket-lang.org/dev
Re: [racket-dev] Character classification
On Tue, Sep 4, 2012 at 3:56 PM, Doug Williams wrote: > I would say your function would be better named is-digit? Good point. However, many of the characters which are char-numeric? are digits too, in other writing systems. > and that the > char-numeric? is exactly what it is intended to be with respect to > Unicode characters, which is what a Racket character represents. What is annoying is that char-numeric? and string->number are not compatible. It would be fine for me to leave char-numeric? as it is and fix string->number to accept and act sensibly on everything that passes char-numeric?. And I'd bet that this new definition of char-numeric? has introduced thousands of covered bugs, which are not exposed only because most the char-numeric? characters outside of #\0 .. #\9 occurs rarely. P. _ Racket Developers list: http://lists.racket-lang.org/dev
Re: [racket-dev] Character classification
On Tue, Sep 4, 2012 at 3:56 PM, Doug Williams wrote: > I would say your function would be better named is-digit? Good point. However, many of the characters which are char-numeric? are digits too, in other writing systems. > and that the > char-numeric? is exactly what it is intended to be with respect to > Unicode characters, which is what a Racket character represents. What is annoying is that char-numeric? and string->number are not compatible. It would be fine for me to leave char-numeric? as it is and fix string->number to accept and act sensibly on everything that passes char-numeric?. And I'd bet that this new definition of char-numeric? has introduced thousands of covered bugs, which are not exposed only because most the char-numeric? characters outside of #\0 .. #\9 occurs rarely. P. _ Racket Developers list: http://lists.racket-lang.org/dev
Re: [racket-dev] Character classification
I would say your function would be better named is-digit? and that the char-numeric? is exactly what it is intended to be with respect to Unicode characters, which is what a Racket character represents. On Tue, Sep 4, 2012 at 4:37 AM, Pierpaolo Bernardi wrote: > The non-cooperation between char-numeric? and string->number is very annoying. > > I had to resort to: > > (define (my-char-numeric? c) > (char<=? #\0 c #\9)) > > Maybe I am missing a function similar to my-char-numeric? somewhere in > the Racket docs? > > FWIW, my humble opinion is that char-numeric? should be defined as the > my- version above. The Unicode category, if that's what one wants, can > be accessed with char-general-category. > > Cheers > P. > _ > Racket Developers list: > http://lists.racket-lang.org/dev _ Racket Developers list: http://lists.racket-lang.org/dev
Re: [racket-dev] Character classification
On Tue, Sep 4, 2012 at 3:11 PM, Jens Axel Søgaard wrote: > Since the R5RS version of char-numeric? (according to the documentation) > tests for the ten digits, you can use: > > (require (only-in r5rs char-numeric?)) Thanks Jens Axel. However, the r5rs version appears to be the same as the Racket version. Tested with: #lang r5rs (define (test) (let again ((i 0)) (cond ((< i #xD800) (let ((c (integer->char i))) (cond ((char-numeric? c) (display (list i c)) (newline))) (again (+ i 1))) _ Racket Developers list: http://lists.racket-lang.org/dev
Re: [racket-dev] Character classification
Since the R5RS version of char-numeric? (according to the documentation) tests for the ten digits, you can use: (require (only-in r5rs char-numeric?)) /Jens Axel 2012/9/4 Pierpaolo Bernardi : > The non-cooperation between char-numeric? and string->number is very annoying. > > I had to resort to: > > (define (my-char-numeric? c) > (char<=? #\0 c #\9)) > > Maybe I am missing a function similar to my-char-numeric? somewhere in > the Racket docs? > > FWIW, my humble opinion is that char-numeric? should be defined as the > my- version above. The Unicode category, if that's what one wants, can > be accessed with char-general-category. > > Cheers > P. > _ > Racket Developers list: > http://lists.racket-lang.org/dev -- -- Jens Axel Søgaard _ Racket Developers list: http://lists.racket-lang.org/dev
Re: [racket-dev] Changing call/cc
At Thu, 30 Aug 2012 11:36:55 -0400, Asumu Takikawa wrote: > On 2012-08-30 06:53:58 -0600, Matthew Flatt wrote: > > I think this combination of replacing both `call/cc' and `dynamic-wind' > > would be equivalent to a smaller change to the semantics of `call/cc', > > which is that it behaves as it does now if there's a shared > > `dynamic-wind' between the source and target continuations, but it > > behaves like your replacement `call/cc' if there's no intervening > > prompt (which addresses the reasoning problem). Also, implementing the > > change directly in the existing `call/cc' implementation sounds fairly > > easy to me. > > Sam and I discussed this some more, and we think it sounds workable and > will go and try to add it to the Redex model and see what tests fail. We > were concerned about one thing though: it sounds like this would modify > the behavior of `call/cc` depending on whether or not you put a > `dynamic-wind` in your continuation. > > That also means that a programmer who installs a `dynamic-wind` might > get fewer abort handlers run than expected, or perhaps gets *more* run > than expected since they either didn't install the `dynamic-wind` or > they passed the continuation out of the `dynamic-wind` to a different > context and invoked it there. > > Is that a fair point or are we misunderstanding your proposed semantics? Yes, that's true. I don't think there will be a difference for typical uses of `call/cc' and typical abort handlers, though. And as I understand it, we're not at this point trying to make `call/cc' work seamlessly, but instead support it reasonably well for backward compatibility. _ Racket Developers list: http://lists.racket-lang.org/dev
[racket-dev] Character classification
The non-cooperation between char-numeric? and string->number is very annoying. I had to resort to: (define (my-char-numeric? c) (char<=? #\0 c #\9)) Maybe I am missing a function similar to my-char-numeric? somewhere in the Racket docs? FWIW, my humble opinion is that char-numeric? should be defined as the my- version above. The Unicode category, if that's what one wants, can be accessed with char-general-category. Cheers P. _ Racket Developers list: http://lists.racket-lang.org/dev
[racket-dev] Character classification
The non-cooperation between char-numeric? and string->number is very annoying. I had to resort to: (define (my-char-numeric? c) (char<=? #\0 c #\9)) Maybe I am missing a function similar to my-char-numeric? somewhere in the Racket docs? FWIW, my humble opinion is that char-numeric? should be defined as the my- version above. The Unicode category, if that's what one wants, can be accessed with char-general-category. Cheers P. _ Racket Developers list: http://lists.racket-lang.org/dev
