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- But I've also got a
structure called Record, okay?

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Now you might wonder why
I need two structures.

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The Record structure, oh,
it implements equality

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and partial equality traits.

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That's an interesting observation.

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A Record is a kind of
like a summary of a visit.

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It just says what date did the visit start

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and how many days was it, like so.

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So if you compare a visit structure,

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and a record structure
to see what they contain

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let's think about that.

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So a visit structure will
contain the start date,

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like the, we went skiing on
the 1st of April, 2023 to

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St. Anton in Austria,
what a beautiful place.

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We were only there for
a week, unfortunately.

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We came back on the 8th of April
23 and it was to St. Anton.

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That's my favorite ski resort.

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That would be a visit.

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A record on the other hand,

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would kind of be a summary of that.

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A record would just say
it was the 1st of April

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when you went, 23.

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So it says basically the the date when

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the visit started and the number
of days that you were away.

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So the number of days I've been away

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would be seven, isn't it?

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I think.

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Seven days away like that.

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So the visit information
is what I read from a file.

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So on my file system I'll
read visit information,

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but it's the record that I'm going to use

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in all of my work ins.

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When I say, when I'm trying to calculate

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the total number of days I've been away,

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it'll be this number
that I'm going to use.

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This record is like a
summary of the visit,

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and it's only this number
really that matters.

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And when I output all the information

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about how many days I've been away,

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it's this record information
that'll be displayed.

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It'll say you were away on the

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1st of April 23 for seven days.

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So it's like a simplified summary.

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I didn't envisage having
this record structure.

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Initially I envisaged just using visit,

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but then I kept on having to do lots of

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like give me the number of
days between the start and end.

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And I thought I may as well just calculate

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that once and store it in here.

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So that's the purpose,

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the implementation is
actually really simple.

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I've just got a effectively a constructor

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to initialize the date
and the number of days,

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it implements the display trait.

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So it can output a record
using the default formatter,

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number of days, what date did you start.

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It also implements the odd
trait and the partial odd trait.

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Remember those?

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The partial odd trait basically
means that you can say,

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you could say something like this.

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You could say record one, less
than record two, like that.

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Or record one greater
than equal to record two.

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So when you implement the partial comp,

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it basically, the
algorithm here will allow

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records to be compared for equality,

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less than equal to, I should say.

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And then the odd trait above it.

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The odd trait, basically
it has a max function,

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and a min function and a
clamp function, remember that?

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Where you can bound a value

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to be within a certain range,
a given maximum and a minimum.

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So you could say, for
example, something like

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if I have record one, and
I call max a record two,

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it will gimme back the larger

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of the two or the smaller of the two.

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So this record structure turned out to be

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quite useful actually, as
we will see in the code.

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So there we are.

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It's quite, it's not difficult really.

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I think it's just tricky
rather than being difficult.

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And you need to have a look
online at the documentation

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for NaiveDate to see what
options and functions you've got.

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So here is the
documentation for NaiveDate.

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It's the NaiveDate structure

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in the Naive Module in the Chrono Crate.

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And you can see all the
different functions it has here,

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for doing date time related operations.

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So the function that we called
was signed duration since,

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you can give it one NaiveDate
and another NaiveDate,

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and it returns a duration, okay?

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And the duration basically
allows you to convert

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to days and minutes and such like.

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So there we are.

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That's good coverage, I think,

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of how to do date handling in Rust.