Re: Evaluating a Lua expression at the end

["Procházka Lukáš Ing. - Pontex s. r. o." <LPr@pontex.cz>]

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Hello,

another single-pass approach, which uses the fact that you know the questions and their point "weights" in advance is to form questions into a Lua table and evaluate the total first:

----
local C = context

local tab =
{ {"Question 1", 10, },
   {"Question 2", 20, },
   {"Question 3", 30, },
}

local n = 0

for _, v in ipairs(tab) do local q, n1 = unpack(v); n = n + n1 end

-- Or: for _, v in ipairs(tab) do n = n + v[2] end

local f = function(it)
   local q, n1 = unpack(it)

   n = n + n1

   C(q .. ": " .. n)
   C.par()
end

C.starttext()
   C("Total score: " .. n)
   C.par()

   n = 0 -- Reset

   f(tab[1])
   f(tab[2])
   f(tab[3])

   -- Or: for _, v in ipairs(tab) do f(v) end
C.stoptext()
----

Best regards,

Lukas


> Thanks for the response. I am looking at something like this:
>
> ==============
> \starttext
> \directlua{total = 0}
> \title{Homework 1}
>
> Total score: \directlua{tex.print(total);}
>
> Question 1 (3 points)
> \directlua{total = total + 3}
>
> Question 2 (4 points)
> \directlua{total = total + 4}
>
> Question 3 (5 points)
> \directlua{total = total + 5}
>
> \stoptext
> ==============
>
> I expect the “Total score” to be followed by “12”, but I don't know
> how to get that (or whether that is even possible).
>
> Thanks.
>
> Kumar


-- 
Ing. Lukáš Procházka | mailto:LPr@pontex.cz
Pontex s. r. o.      | mailto:pontex@pontex.cz | http://www.pontex.cz
Bezová 1658
147 14 Praha 4

Tel: +420 241 096 751
Fax: +420 244 461 038

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local C = context

local tab =
{ {"Question 1", 10, },
  {"Question 2", 20, },
  {"Question 3", 30, },
}

local n = 0

for _, v in ipairs(tab) do local q, n1 = unpack(v); n = n + n1 end

local f = function(it)
  local q, n1 = unpack(it)

  n = n + n1

  C(q .. ": " .. n)
  C.par()
end

C.starttext()
  C("Total score: " .. n)
  C.par()

  n = 0 -- Reset

  f(tab[1])
  f(tab[2])
  f(tab[3])
C.stoptext()

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