* Reading ConTeXt metadata values into Lua @ 2021-10-16 4:00 Ramkumar KB via ntg-context 2021-10-16 8:33 ` Wolfgang Schuster via ntg-context 0 siblings, 1 reply; 4+ messages in thread From: Ramkumar KB via ntg-context @ 2021-10-16 4:00 UTC (permalink / raw) To: mailing list for ConTeXt users; +Cc: Ramkumar KB [-- Attachment #1.1: Type: text/plain, Size: 884 bytes --] Hello All, I was trying to read the value of '\totalnumberofpages' into lua to do something with it. As an example, see below. Now, as I understand it, my example would not work as TeX gets the first go at this and therefore the variable 'pages' is the string '\totalnumberofpages' and not the actual value itself. And Lua cannot process this "calculation". I tried to go thru the manual - *cld-mkiv.pdf *- in the distro but could not catch on how to read a metadata value (not print). I am sure that I am missing a small trick somewhere (or is it something more involved?). \startluacode function myFancyCalculations(pages) -- some fancy stuff but as an example local myCal = tonumber(pages) + 1 return myCal \stopluacode \starttext \blah \ctxlua{context(myFancyCalculations("\\totalnumberofpages"))} \stoptext Thank you in advance for any tips. best regards, Ramkumar [-- Attachment #1.2: Type: text/html, Size: 2284 bytes --] [-- Attachment #2: Type: text/plain, Size: 493 bytes --] ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://context.aanhet.net archive : https://bitbucket.org/phg/context-mirror/commits/ wiki : http://contextgarden.net ___________________________________________________________________________________ ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Reading ConTeXt metadata values into Lua 2021-10-16 4:00 Reading ConTeXt metadata values into Lua Ramkumar KB via ntg-context @ 2021-10-16 8:33 ` Wolfgang Schuster via ntg-context 2021-10-16 8:59 ` Hans Hagen via ntg-context 0 siblings, 1 reply; 4+ messages in thread From: Wolfgang Schuster via ntg-context @ 2021-10-16 8:33 UTC (permalink / raw) To: mailing list for ConTeXt users, Ramkumar KB via ntg-context Cc: Wolfgang Schuster [-- Attachment #1.1: Type: text/plain, Size: 1717 bytes --] Ramkumar KB via ntg-context schrieb am 16.10.2021 um 06:00: > Hello All, > > I was trying to read the value of '\totalnumberofpages' into lua to do > something with it. As an example, see below. > > Now, as I understand it, my example would not work as TeX gets the > first go at this and therefore the variable 'pages' is the string > '\totalnumberofpages' and not the actual value itself. And Lua cannot > process this "calculation". > > I tried to go thru the manual - *cld-mkiv.pdf *- in the distro but > could not catch on how to read a metadata value (not print). I am sure > that I am missing a small trick somewhere (or is it something more > involved?). > > \startluacode > function myFancyCalculations(pages) > -- some fancy stuff but as an example > local myCal = tonumber(pages) + 1 > return myCal > \stopluacode > \starttext > > \blah > > \ctxlua{context(myFancyCalculations("\\totalnumberofpages"))} > > \stoptext Everything gets easier when you use the Lua functions to access the counter values but be aware the values can be wrong when you're at a page break. \startbuffer[pagenumber] \startluacode context.starttabulate() context.NC() context("Current page") context.EQ() context(structures.counters.get("realpage",1,"number")) context.NC() context.NR() context.NC() context("Last page") context.EQ() context(structures.counters.get("realpage",1,"last")) context.NC() context.NR() context.stoptabulate() \stopluacode \stopbuffer \starttext \dorecurse {\randomnumber{5}{10}} {\getbuffer[pagenumber] \page} \stoptext Wolfgang [-- Attachment #1.2: Type: text/html, Size: 3276 bytes --] [-- Attachment #2: Type: text/plain, Size: 493 bytes --] ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://context.aanhet.net archive : https://bitbucket.org/phg/context-mirror/commits/ wiki : http://contextgarden.net ___________________________________________________________________________________ ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Reading ConTeXt metadata values into Lua 2021-10-16 8:33 ` Wolfgang Schuster via ntg-context @ 2021-10-16 8:59 ` Hans Hagen via ntg-context 2021-10-17 8:06 ` Ramkumar KB via ntg-context 0 siblings, 1 reply; 4+ messages in thread From: Hans Hagen via ntg-context @ 2021-10-16 8:59 UTC (permalink / raw) To: mailing list for ConTeXt users; +Cc: Hans Hagen On 10/16/2021 10:33 AM, Wolfgang Schuster via ntg-context wrote: > Ramkumar KB via ntg-context schrieb am 16.10.2021 um 06:00: >> Hello All, >> >> I was trying to read the value of '\totalnumberofpages' into lua to do >> something with it. As an example, see below. >> >> Now, as I understand it, my example would not work as TeX gets the >> first go at this and therefore the variable 'pages' is the string >> '\totalnumberofpages' and not the actual value itself. And Lua cannot >> process this "calculation". >> >> I tried to go thru the manual - *cld-mkiv.pdf *- in the distro but >> could not catch on how to read a metadata value (not print). I am sure >> that I am missing a small trick somewhere (or is it something more >> involved?). >> >> \startluacode >> function myFancyCalculations(pages) >> -- some fancy stuff but as an example >> local myCal = tonumber(pages) + 1 >> return myCal >> \stopluacode >> \starttext >> >> \blah >> >> \ctxlua{context(myFancyCalculations("\\totalnumberofpages"))} >> >> \stoptext > > Everything gets easier when you use the Lua functions to access the > counter values but be aware the values can be wrong when you're at a > page break. > > \startbuffer[pagenumber] > \startluacode > context.starttabulate() > context.NC() > context("Current page") > context.EQ() > context(structures.counters.get("realpage",1,"number")) > context.NC() > context.NR() > context.NC() > context("Last page") > context.EQ() > context(structures.counters.get("realpage",1,"last")) > context.NC() > context.NR() > context.stoptabulate() > \stopluacode > \stopbuffer > > \starttext > > \dorecurse > {\randomnumber{5}{10}} > {\getbuffer[pagenumber] > \page} > > \stoptext As addendum ... The problem in general with macros is that one doesn't really knows by looking at the name what actually happens when it expands, which can be a lot. Now, because \totalnumberofpages is supposed to 'return' a number and not typeset something styled (which itself involved macro expansion) you can actually do this: \startluacode local n = tokens.getters.macro("totalnumberofpages",true) print(">>>",type(n),n) \stopluacode but beware of the fact that you actually get back a string: \startluacode local n = tokens.getters.macro("totalnumberofpages",true) print(">>>",type(n),n) local n = tonumber(n) print(">>>",type(n),n) \stopluacode etc etc Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl ----------------------------------------------------------------- ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://context.aanhet.net archive : https://bitbucket.org/phg/context-mirror/commits/ wiki : http://contextgarden.net ___________________________________________________________________________________ ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Reading ConTeXt metadata values into Lua 2021-10-16 8:59 ` Hans Hagen via ntg-context @ 2021-10-17 8:06 ` Ramkumar KB via ntg-context 0 siblings, 0 replies; 4+ messages in thread From: Ramkumar KB via ntg-context @ 2021-10-17 8:06 UTC (permalink / raw) To: mailing list for ConTeXt users; +Cc: Ramkumar KB [-- Attachment #1.1: Type: text/plain, Size: 3923 bytes --] Hans / Wolfgang, Thank you for your quick feedback and the tips. Yes, this works for now. In general, I will try to avoid going into such "deep-end" APIs (at least for now, until such time I read all the manuals in depth!). IMHO, the standard ConTeXt system is itself quite powerful for 98% of the Typesetting usecases. best regards, Ramkumar On Sat, Oct 16, 2021 at 4:59 PM Hans Hagen via ntg-context < ntg-context@ntg.nl> wrote: > On 10/16/2021 10:33 AM, Wolfgang Schuster via ntg-context wrote: > > Ramkumar KB via ntg-context schrieb am 16.10.2021 um 06:00: > >> Hello All, > >> > >> I was trying to read the value of '\totalnumberofpages' into lua to do > >> something with it. As an example, see below. > >> > >> Now, as I understand it, my example would not work as TeX gets the > >> first go at this and therefore the variable 'pages' is the string > >> '\totalnumberofpages' and not the actual value itself. And Lua cannot > >> process this "calculation". > >> > >> I tried to go thru the manual - *cld-mkiv.pdf *- in the distro but > >> could not catch on how to read a metadata value (not print). I am sure > >> that I am missing a small trick somewhere (or is it something more > >> involved?). > >> > >> \startluacode > >> function myFancyCalculations(pages) > >> -- some fancy stuff but as an example > >> local myCal = tonumber(pages) + 1 > >> return myCal > >> \stopluacode > >> \starttext > >> > >> \blah > >> > >> \ctxlua{context(myFancyCalculations("\\totalnumberofpages"))} > >> > >> \stoptext > > > > Everything gets easier when you use the Lua functions to access the > > counter values but be aware the values can be wrong when you're at a > > page break. > > > > \startbuffer[pagenumber] > > \startluacode > > context.starttabulate() > > context.NC() > > context("Current page") > > context.EQ() > > context(structures.counters.get("realpage",1,"number")) > > context.NC() > > context.NR() > > context.NC() > > context("Last page") > > context.EQ() > > context(structures.counters.get("realpage",1,"last")) > > context.NC() > > context.NR() > > context.stoptabulate() > > \stopluacode > > \stopbuffer > > > > \starttext > > > > \dorecurse > > {\randomnumber{5}{10}} > > {\getbuffer[pagenumber] > > \page} > > > > \stoptext > > As addendum ... The problem in general with macros is that one doesn't > really knows by looking at the name what actually happens when it > expands, which can be a lot. Now, because \totalnumberofpages is > supposed to 'return' a number and not typeset something styled (which > itself involved macro expansion) you can actually do this: > > \startluacode > local n = tokens.getters.macro("totalnumberofpages",true) > print(">>>",type(n),n) > \stopluacode > > but beware of the fact that you actually get back a string: > > \startluacode > local n = tokens.getters.macro("totalnumberofpages",true) > print(">>>",type(n),n) > local n = tonumber(n) > print(">>>",type(n),n) > \stopluacode > > etc etc > > Hans > > ----------------------------------------------------------------- > Hans Hagen | PRAGMA ADE > Ridderstraat 27 | 8061 GH Hasselt | The Netherlands > tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl > ----------------------------------------------------------------- > > ___________________________________________________________________________________ > If your question is of interest to others as well, please add an entry to > the Wiki! > > maillist : ntg-context@ntg.nl / > http://www.ntg.nl/mailman/listinfo/ntg-context > webpage : http://www.pragma-ade.nl / http://context.aanhet.net > archive : https://bitbucket.org/phg/context-mirror/commits/ > wiki : http://contextgarden.net > > ___________________________________________________________________________________ > [-- Attachment #1.2: Type: text/html, Size: 5818 bytes --] [-- Attachment #2: Type: text/plain, Size: 493 bytes --] ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://context.aanhet.net archive : https://bitbucket.org/phg/context-mirror/commits/ wiki : http://contextgarden.net ___________________________________________________________________________________ ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-10-17 8:06 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-10-16 4:00 Reading ConTeXt metadata values into Lua Ramkumar KB via ntg-context 2021-10-16 8:33 ` Wolfgang Schuster via ntg-context 2021-10-16 8:59 ` Hans Hagen via ntg-context 2021-10-17 8:06 ` Ramkumar KB via ntg-context
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