El mié, 24 de mar. de 2021 a la(s) 16:47, Hans Hagen ([email protected])
escribió:
> On 3/24/2021 6:33 PM, Jairo A. del Rio wrote:
> > Hi, Hans. Here's my (miserably failing) attempt:
> >
> > \definedataset[nicedata]
> >
> > \starttext
> >
> > \startluacode
> >
> > local name = "nicedata"
> >
> >
> > -- For exposition only
> >
> > local function dofactorial(n)
> >
> > local function inner(c,m)
> >
> > if m<2 then return c end
> >
> > return inner(c*m, m-1)
> >
> > end
> >
> > return inner(1,n)
> >
> > end
> >
> >
> > local function factorial(n)
> >
> > local stringn = tostring(n)
> >
> > if job.datasets.collected[name] then
> >
> > return job.datasets.collected[name].factorial[stringn]
> >
> > else
> >
> > local mydata = {[stringn] = tostring(dofactorial(n))}
> >
> > job.datasets.setdata{
> >
> > name = name,
> >
> > tag = "factorial",
> >
> > data = mydata
> >
> > }
> >
> > return mydata[stringn]
> >
> > end
> >
> > end
> >
> >
> > interfaces.implement{
> >
> > name = "factorial",
> >
> > public = true,
> >
> > arguments = {"string"},
> >
> > actions = {tonumber, factorial, context}
> >
> > }
> >
> >
> > \stopluacode
> >
> > \factorial{7}
> >
> > \stoptext
> >
> >
> > What happens is that, in each run, both the first and the second
> > conditions are met, so the compilation is twice as slow, the opposite
> > result of what I meant to do. How do I fix that?
>
> \definedataset[nicedata]
>
> \starttext
>
> \startluacode
>
> local function dofactorial(n)
> local function inner(c,m)
> if m < 2 then
> return c
> else
> return inner(c*m, m-1)
> end
> end
> return inner(1,n)
> end
>
> local function factorial(n)
> local data = job.datasets.getdata("factorials","list")
> if not data then
> data = { }
> end
> local f = data[n]
> if not f then
> f = dofactorial(n)
> data[n] = f
> end
> job.datasets.setdata {
> name = "factorials",
> tag = "list",
> data = data
> }
> return f
> end
>
> interfaces.implement{
> name = "factorial",
> public = true,
> arguments = { "integer" },
> actions = { factorial, context }
> }
>
> \stopluacode
>
> \dorecurse {20} {
> \factorial #1 \relax
> }
>
> \stoptext
>
>
It does exactly what I need. It's good to know datasets can be directly
generated, too. Thank you a lot!
> but you probably don't gain much as these factorials are not that slow
> (if you use them many times in a document you can just cache them)
>
>
It was only a toy example. I intend to work with way larger numbers. :)
> 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
> -----------------------------------------------------------------
>
Best regards,
Jairo
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