Re: [bug-recutils] New %constraint special field and => operator

[Michał Masłowski]

Hello.

> - A new sex operator => (implies) with semantics:
>
>     A => B means !A || (A && B)

I don't see any obvious uses for it outside %constraint.

> - A new special field %constraint, which adds a sex-driven constraint to
>   the records of that type.  Example:
>
>   %rec: Task
>   %type: Start,End date
>   %constraint: Start << End
>   %constraint: Status = 'CLOSED' => #End
>
>   Meaning that for any task the Start date cannot be after the Start
>   date (which makes sense :D) and that if a class is closed then it must
>   have an End date.

Planned to use recutils for a database where the previously available
containts weren't strict enough, this will probably solve that issue
(although won't try it before the indexing).

> PS: Is %constraint the better name for this special field?

It's the most general constraint field, so the name is appropriate
here.  Unless you have other ideas for it.

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