[racket-users] tail-position in for/list form?
Question: In the definitions window of DrRacket: #lang racket (for/list ((x (in-list '(a b c))) (k (in-naturals))) (cons k x)) When I place the cursor on the leftmost parenthesis of the for/list form, I see a pink arrow to the subexpr (cons k x). How can (cons k x) possibly be in tail position of the whole for/list form? All blue binding arrows are as I expect. (DrRacket, version 6.6 [3m]) Jos -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] How do you use the 'make-brush' '#:transformation' vector[11] argument?
Thanks I just found the documentation for 'get-transformation' which details the matrix: http://docs.racket-lang.org/draw/dc___.html#%28meth._%28%28%28lib._racket%2Fdraw..rkt%29._dc~3c~25~3e%29._get-transformation%29%29 ...and submitted a pull-request to add the link to 'get-transformation' from 'make-brush': https://github.com/racket/draw/pull/6 Thanks again, Stephen On Wednesday, August 17, 2016 at 12:08:51 PM UTC+1, Jens Axel Søgaard wrote: > Hi Stephen, > > > There is a brief description on transformations in the documentation for the > method get-transformation of dc%. > > > > Basically the vector part is the coefficients xx xy yx yy x0 y0 (in that > order - I think - > maybe xy and yx are swapped) of an affine transformation: > > > > xnew = xx*x + xy*y + x0 > > ynew = yx*x + yy*y + y0 > > The last five numbers sets origin, scale and rotation. These numbers are > affected by set-origin, set-scale and set-rotation. > > In MetaPict I decided to stick to the affine transformation and ignore the > second part: > > > > (define (set-transformation dc t) > (send dc set-transformation > (vector (trans->vector t) > 0 0 ; x and y origin > 1 1 ; x and y scale > 0))) ; rotation > > > The code here defines transformations corresponding to the one used in > MetaPost: > > > https://github.com/soegaard/metapict/blob/master/metapict/trans.rkt > > > > /Jens Axel > > > > > 2016-08-17 10:54 GMT+02:00 spdegabrielle : > Hi, > > > > How do you use the 'make-brush' '#:transformation' vector[11] argument? > > > > What should the vector contain? > > > > http://docs.racket-lang.org/draw/Drawing_Functions.html#%28def._%28%28lib._racket%2Fdraw..rkt%29._make-brush%29%29 > > > > Kind regards, > > > > Stephen > > > > -- > > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > > To unsubscribe from this group and stop receiving emails from it, send an > email to racket-users...@googlegroups.com. > > For more options, visit https://groups.google.com/d/optout. > > > > > > -- > > -- > Jens Axel Søgaard -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Re: Linux packages?
The official release for openSuse leap is only 5.3 -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] Re: Linux packages?
On Tue, Aug 16, 2016 at 10:46:51PM -0700, Andreas Olsson wrote: > If there was packages for the major dists like fedora, ubuntu and suse on the > racket homepage it would be easier for people to get. It would help racket > becoming a little more known and used. Debian has a racket package. Also a racket-doc package, and a racket-common package. (this latter presumably for files that are machine-independent). aptitude install racket should install it, without haveing to hand-edit sources.list. Since Ubuntu is a Debian derivative, I'd be surprised if it didn't have the same. -- hendrik -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] How do you use the 'make-brush' '#:transformation' vector[11] argument?
Hi Stephen, There is a brief description on transformations in the documentation for the method get-transformation of dc%. Basically the vector part is the coefficients xx xy yx yy x0 y0 (in that order - I think - maybe xy and yx are swapped) of an affine transformation: xnew = xx*x + xy*y + x0 ynew = yx*x + yy*y + y0 The last five numbers sets origin, scale and rotation. These numbers are affected by set-origin, set-scale and set-rotation. In MetaPict I decided to stick to the affine transformation and ignore the second part: (define (set-transformation dc t) (send dc set-transformation (vector (trans->vector t) 0 0 ; x and y origin 1 1 ; x and y scale 0))) ; rotation The code here defines transformations corresponding to the one used in MetaPost: https://github.com/soegaard/metapict/blob/master/metapict/trans.rkt /Jens Axel 2016-08-17 10:54 GMT+02:00 spdegabrielle : > Hi, > > How do you use the 'make-brush' '#:transformation' vector[11] argument? > > What should the vector contain? > > http://docs.racket-lang.org/draw/Drawing_Functions.html#% > 28def._%28%28lib._racket%2Fdraw..rkt%29._make-brush%29%29 > > Kind regards, > > Stephen > > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to racket-users+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- -- Jens Axel Søgaard -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[racket-users] How do you use the 'make-brush' '#:transformation' vector[11] argument?
Hi, How do you use the 'make-brush' '#:transformation' vector[11] argument? What should the vector contain? http://docs.racket-lang.org/draw/Drawing_Functions.html#%28def._%28%28lib._racket%2Fdraw..rkt%29._make-brush%29%29 Kind regards, Stephen -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [racket-users] racket/db, creating queries from fetched values
On 8/16/2016 3:57 PM, Kristjan Siimson wrote: Basically when I said "query" I meant the SQL-language strings, which can be copy-pasted and executed independently. Some utilities (Percona tools) call it "dry run"; the queries are printed as strings for end user verification, and they never reach the database. For example pt-table-sync in Percona toolkit (https://www.percona.com/doc/percona-toolkit/2.2/pt-table-sync.html) has --dry-run and --print options. I have a more application-specific DBA tool in mind for mitigating issues in a legacy application. Of course it's a very specific use case, and as direct queries lend to injection attacks, I would be somewhat surprised if it was possible. I still have hope that I have overlooked something. :-) Sorry, there is no built in way to do this. But it seems like it should be pretty easy to roll your own. The most flexible way to convert ordinary values to text is with the *racket/format* library. https://docs.racket-lang.org/reference/strings.html?q=racket%2Fformat#%28mod-path._racket%2Fformat%29 The SRFI-48 library provides *format* which is similar to C's sprintf(). https://docs.racket-lang.org/srfi/srfi-std/srfi-48.html For structured types like dates/times there are separate printing functions ... you just need to look up the type. Be aware that SQL dates and times are separate from Racket dates and times. You may need to convert types from one to the other to get what you want. https://docs.racket-lang.org/db/util.html?q=date-%3Esql#%28mod-path._db%2Futil%2Fdatetime%29 For string manipulation Racket has whatever you need. Simplest is probably regex (built in). Look at *regexp-replaces* for an easy way to do multiple string substitutions. https://docs.racket-lang.org/reference/strings.html https://docs.racket-lang.org/reference/regexp.html https://docs.racket-lang.org/reference/regexp.html?q=regex#%28def._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._regexp-replaces%29%29 George -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
