Why are tristate booleans a Calibre-wide setting?

ownedbycats · 11-03-2020, 04:26 PM

I find it a bit strange that Calibre has a lot of options for custom columns, except for whether a column is bistate or tristate. You can't have both of them in different columns in the same library.

I suspect it's due to technical limitations rather than a design choice (considering the workaround of "show checkmarks" to make a psuedobool), but why is this?

hobnail · 11-03-2020, 05:28 PM

I'm not sure what you mean by bistate or tristate. I'm only using the Yes/No type which are all tristate and I have 3 columns using them.

chaley · 11-03-2020, 05:40 PM

My thought was either your mental model a) is that yes/no is exactly that (bistate), or b) that "I don't know" is an acceptable answer (tristate). Under this point of view it makes no sense to offer both at the same time. It was not intended as a shortcut for avoiding thinking about the problem.

If I had it to do again I would not offer bistate, instead using default values to map "I don't know" to "No".

ownedbycats · 11-03-2020, 06:12 PM

Quote:

Originally Posted by hobnail

I'm not sure what you mean by bistate or tristate. I'm only using the Yes/No type which are all tristate and I have 3 columns using them.

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I just found it interesting that this isn't a column-specific setting.

ownedbycats · 11-03-2020, 06:21 PM

I think the reason I switched to bistate is because I ran into an issue with a plugin (Reading List, I think?) where it attempting to set #bool:false or #bool:no instead cleared the value.

hobnail · 11-03-2020, 07:03 PM

I never noticed that setting. I'm guessing it's app-wide simplifies things otherwise making it per column would mean having two different types of yes/no choices in the column builder.

My memory from my programming days is that in databases the empty or Null choice was considered a design misfeature because it tended to introduce hard to find programming errors, or maybe it was that queries were more difficult to get right. Although in databases the null value could be used in any type, not just true/false yes/no, but regardless was a bad "code smell".

ownedbycats · 11-03-2020, 07:15 PM

I know an earlier version of Calibre had a glitch with column icons/emblems showing up improperly with bistate bools because it was still flagged as 'undefined' in the database.

11-03-2020, 04:26 PM	#1
ownedbycats Custom User Title Posts: 10,969 Karma: 75337983 Join Date: Oct 2018 Location: Canada Device: Kobo Libra H2O, formerly Aura HD	Why are tristate booleans a Calibre-wide setting? I find it a bit strange that Calibre has a lot of options for custom columns, except for whether a column is bistate or tristate. You can't have both of them in different columns in the same library. I suspect it's due to technical limitations rather than a design choice (considering the workaround of "show checkmarks" to make a psuedobool), but why is this?

11-03-2020, 06:21 PM	#5
ownedbycats Custom User Title Posts: 10,969 Karma: 75337983 Join Date: Oct 2018 Location: Canada Device: Kobo Libra H2O, formerly Aura HD	I think the reason I switched to bistate is because I ran into an issue with a plugin (Reading List, I think?) where it attempting to set #bool:false or #bool:no instead cleared the value. Last edited by ownedbycats; 11-03-2020 at 06:34 PM.

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11-03-2020, 05:28 PM	#2
hobnail Running with scissors Posts: 1,586 Karma: 14328510 Join Date: Nov 2019 Device: none	I'm not sure what you mean by bistate or tristate. I'm only using the Yes/No type which are all tristate and I have 3 columns using them.

11-03-2020, 05:40 PM	#3
chaley Grand Sorcerer Posts: 12,443 Karma: 8012886 Join Date: Jan 2010 Location: Notts, England Device: Kobo Libra 2	My thought was either your mental model a) is that yes/no is exactly that (bistate), or b) that "I don't know" is an acceptable answer (tristate). Under this point of view it makes no sense to offer both at the same time. It was not intended as a shortcut for avoiding thinking about the problem. If I had it to do again I would not offer bistate, instead using default values to map "I don't know" to "No".

11-03-2020, 07:03 PM	#6
hobnail Running with scissors Posts: 1,586 Karma: 14328510 Join Date: Nov 2019 Device: none	I never noticed that setting. I'm guessing it's app-wide simplifies things otherwise making it per column would mean having two different types of yes/no choices in the column builder. My memory from my programming days is that in databases the empty or Null choice was considered a design misfeature because it tended to introduce hard to find programming errors, or maybe it was that queries were more difficult to get right. Although in databases the null value could be used in any type, not just true/false yes/no, but regardless was a bad "code smell".

11-03-2020, 07:15 PM	#7
ownedbycats Custom User Title Posts: 10,969 Karma: 75337983 Join Date: Oct 2018 Location: Canada Device: Kobo Libra H2O, formerly Aura HD	I know an earlier version of Calibre had a glitch with column icons/emblems showing up improperly with bistate bools because it was still flagged as 'undefined' in the database.

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