A History of Lua (2001)

Re:A History of Lua (2001) by lenkite on Wednesday August 10, 2022 @06:21AM (#32409830)

Lua tables make no distinction between a table value being nil and the corresponding key not existing in the table necessitating hacks like: http://lua-users.org/wiki/StoringNilsInTables

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Re:A History of Lua (2001) by edflsafoiewq on Wednesday August 10, 2022 @06:32AM (#32409893)

Yeah, that's the point of nil. If you're trying to store it in a table, you're just fighting the language. Is there a good motivation for doing that?

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Re:A History of Lua (2001) by samatman on Wednesday August 10, 2022 @10:49AM (#32412940)

I've done this on two rare occasions: round-tripping 'null' in JSON and 'NULL' in database queries.

My solution, which was perhaps overly cute, was a table canonically named No, which is callable such that No(nil), No(false), and No(No) all return true.

So I could say

   if No(value) then

When I needed to do conditional logic which excludes those reified null values, which isn't often.

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