[NTG-context] lpdf.checkedkey has problem with false values

Hans Hagen pragma at wxs.nl
Mon Sep 15 19:12:02 CEST 2014


On 9/15/2014 6:12 PM, Michail Vidiassov wrote:
> Dear Aditya, Peter and All,
>
>> I think that what Peter meant was:
>
> the real issue is not teaching me lua and improving the style of my example,
> but my complaint (correct or not) about inability of lpdf.checkedkey

it looks like your question was not clear then

> to correctly fetch false boolean values: they are fetched as nil, just
> as if they were absent or of incorrect type.

well, they're just not treated special

> Please, someone with time and, preferably, authority - take a look at
> lpdf.checkedkey code (5 minutes maximum).
> Talking in general about lua, not knowing what lpdf.checkedkey is,
> does and is supposed to do, does not look like efficient use of time.

you can try this (untested)

function lpdf.checkedkey(t,key,variant)
     local pn = t and t[key]
     if pn then
         local tn = type(pn)
         if tn == variant then
             if variant == "string" then
                 return pn ~= "" and pn or nil
             elseif variant == "table" then
                 return next(pn) and pn or nil
             else
                 return pn
             end
         elseif tn == "string" then
             if variant == "number" then
                 return tonumber(pn)
             elseif variant == "boolean" then
                 return toboolean(pn)
             end
         end
     end
end

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