[PL-sem-jr] [Reminder] PL Jr today at 2

[Artem Pelenitsyn]

Hello everyone,

As a *short* follow-up exercise for today's discussion, I suggest you all
try the following.

Section 7.1.7 of the book introduces the Reader functor `((→) r)` i.e. the
type constructor for all function types accepting a value of type r as an
argument. Just like the Maybe type constructor maps `Int` to `Maybe Int`
etc., Reader r maps `Int` to `r → Int` (a function type from r to Int's),
etc.

Exercise. Find out why (→ r) — a type constructor for function types
*returning* values of type r — is NOT a functor. (The `(→ r)` type
constructor maps `Int` to `Int→ r`, etc.) Where does the definition of
Functor breaks for (→ r)?

Hint: it breaks real quick.

--
Best wishes,
Artem Pelenitsyn

On Thu, 21 Mar 2019 at 11:08 Artem Pelenitsyn <a.pelenitsyn at gmail.com>
wrote:

> Hi everyone,
>
> Nearly a month ago Celeste wrote to Slack channel #pl-sem-jr:
>
> *The pl-sem-jr happens right exactly on my TA hour. Would it be possible
> to move it to almost any other time on Thursday? (besides 10-11--that’s not
> free on the 7th)*
>
> I'd fine with moving to 1pm-2pm instead of current 2pm-3pm. But I guess
> various ppl will have different requirements. So leaving this for today's
> meeting.
>
> --
> Best, Artem
>
> On Thu, 21 Mar 2019 at 11:03 Hyeyoung Shin <shin.hy at husky.neu.edu> wrote:
>
>> Dear juniors,
>>
>> This is a reminder that we have a meeting today at 2 pm (WVH 366).
>>
>> HW: Read Chapter 7. Functors.
>>
>> See you all there!
>>
>> Sincerely,
>>
>> Hyeyoung
>> _______________________________________________
>> Pl-sem-jr mailing list
>> Pl-sem-jr at lists.ccs.neu.edu
>> https://lists.ccs.neu.edu/bin/listinfo/pl-sem-jr
>>
>
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