Evaluating a Lua expression at the end (repeat)
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Dear List, Last year, Hans helped me with this example: \starttext \startluacode local name = nil local temp = 0 function document.startwhatever(s) name = s temp = 0 end function document.addwhatever(n) temp = temp + n context(n) end function document.stopwhatever() job.variables.save("document:temp:"..name,temp) end function document.getwhatever(s) context(job.variables.collected["document:temp:"..s]) end \stopluacode \def\startwhatever[#1]{\ctxlua{document.startwhatever("#1")}} \def\stopwhatever {\ctxlua{document.stopwhatever()}} \def\addwhatever #1{\ctxlua{document.addwhatever(#1)}} \def\getwhatever #1{\ctxlua{document.getwhatever("#1")}} total: \getwhatever{foo} \startwhatever[foo] test 1: \addwhatever{10}\par test 2: \addwhatever{20}\par test 3: \addwhatever{30}\par \stopwhatever \stoptext However, on my current ConTeXt on Debian (2016.05.17.20160523-1), I am unable to get it working. It says: lua error > lua error on line 37 in file /tmp/test.tex: /usr/share/texmf/tex/context/base/mkiv/core-uti.lua:165: attempt to index upvalue 'tobesavedmacros' (a nil value) stack traceback: /usr/share/texmf/tex/context/base/mkiv/core-uti.lua:165: in function 'save' [ctxlua]:14: in function 'stopwhatever' [ctxlua]:1: in main chunk 27 \def\getwhatever #1{\ctxlua{document.getwhatever("#1")}} 28 29 total: \getwhatever{foo} 30 31 \startwhatever[foo] 32 33 test 1: \addwhatever{10}\par 34 test 2: \addwhatever{20}\par 35 test 3: \addwhatever{30}\par 36 37 >> \stopwhatever 38 39 \stoptext 40 41 Could you please suggest a workaround? Thanks. Kumar
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Hi Kumar, the function job.variables.save seems to save the key in job.variables.collected.macros instead of job.variables.collected. The problem is that macros is not created unconditionally, which is why you might run into a »attempt to index a nil value« error without some manual error checking. Therefore I recommend assigning the temp value to job.variables.tobesaved["document:temp:"..name]. Perhaps Hans joins this discussion and schools me about why this could be a bad idea, but so far it works. Also, I'd recommend making all your user level macros protected and check for the optional argument in \startwhatever (otherwise you'll get errors like »Macro doesn't match its definition«). Because I'm really cautious I also use \luaescapestring{#1} (Try for example »foo"bar« as a value without). \starttext \startluacode local name = nil local temp = 0 function document.startwhatever(s) name = s temp = 0 end function document.addwhatever(n) temp = temp + n context(n) end function document.stopwhatever() job.variables.tobesaved["document:temp:"..name] = temp end function document.getwhatever(s) context(job.variables.collected["document:temp:"..s]) end \stopluacode \define\startwhatever{\dosingleempty\dostartwhatever} \def\dostartwhatever[#1]{\ctxlua{document.startwhatever("\luaescapestring{#1}")}} \define \stopwhatever {\ctxlua{document.stopwhatever()}} \define[1]\addwhatever {\ctxlua{document.addwhatever(\luaescapestring{#1})}} \define[1]\getwhatever {\ctxlua{document.getwhatever("\luaescapestring{#1}")}} total: \getwhatever{foo} \startwhatever[foo] test 1: \addwhatever{10}\par test 2: \addwhatever{20}\par test 3: \addwhatever{30}\par \stopwhatever \stoptext On 08/25/2016 01:28 PM, Kumar Appaiah wrote:
Dear List,
Last year, Hans helped me with this example:
\starttext
\startluacode local name = nil local temp = 0
function document.startwhatever(s) name = s temp = 0 end function document.addwhatever(n) temp = temp + n context(n) end function document.stopwhatever() job.variables.save("document:temp:"..name,temp) end function document.getwhatever(s) context(job.variables.collected["document:temp:"..s]) end \stopluacode
\def\startwhatever[#1]{\ctxlua{document.startwhatever("#1")}} \def\stopwhatever {\ctxlua{document.stopwhatever()}} \def\addwhatever #1{\ctxlua{document.addwhatever(#1)}} \def\getwhatever #1{\ctxlua{document.getwhatever("#1")}}
total: \getwhatever{foo}
\startwhatever[foo]
test 1: \addwhatever{10}\par test 2: \addwhatever{20}\par test 3: \addwhatever{30}\par
\stopwhatever
\stoptext
However, on my current ConTeXt on Debian (2016.05.17.20160523-1), I am unable to get it working. It says:
lua error > lua error on line 37 in file /tmp/test.tex:
/usr/share/texmf/tex/context/base/mkiv/core-uti.lua:165: attempt to index upvalue 'tobesavedmacros' (a nil value) stack traceback: /usr/share/texmf/tex/context/base/mkiv/core-uti.lua:165: in function 'save' [ctxlua]:14: in function 'stopwhatever' [ctxlua]:1: in main chunk
27 \def\getwhatever #1{\ctxlua{document.getwhatever("#1")}} 28 29 total: \getwhatever{foo} 30 31 \startwhatever[foo] 32 33 test 1: \addwhatever{10}\par 34 test 2: \addwhatever{20}\par 35 test 3: \addwhatever{30}\par 36 37 >> \stopwhatever 38 39 \stoptext 40 41
Could you please suggest a workaround?
Thanks.
Kumar ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki!
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On Thu, Aug 25, 2016 at 5:49 PM, Henri Menke
Hi Kumar,
the function job.variables.save seems to save the key in job.variables.collected.macros instead of job.variables.collected. The problem is that macros is not created unconditionally, which is why you might run into a »attempt to index a nil value« error without some manual error checking. Therefore I recommend assigning the temp value to job.variables.tobesaved["document:temp:"..name]. Perhaps Hans joins this discussion and schools me about why this could be a bad idea, but so far it works.
Also, I'd recommend making all your user level macros protected and check for the optional argument in \startwhatever (otherwise you'll get errors like »Macro doesn't match its definition«). Because I'm really cautious I also use \luaescapestring{#1} (Try for example »foo"bar« as a value without).
<snipped code> Indeed, this worked! I'll try to understand the internals myself to know what is going on exactly. Thanks for the solution. Kumar
participants (3)
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Henri Menke
-
Kumar Appaiah
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Kumar Appaiah