[Haskell-beginners] Left vs Right

Greg Graham greg at grahamtx.net
Thu Apr 16 21:22:39 UTC 2015


On Thu, Apr 16, 2015 at 3:42 AM emacstheviking <objitsu at gmail.com> wrote:

> "Semantically, "Either left right" can be seen as a container of one or
> zero "right" that contains out-of-band information of type "left" when it's
> empty. So when you fmap over it, you only touch the content, not the
> out-of-band information."
>
> Yup. Whatever he said. ;)  ...that's bordering on monadic comparison
> tutorials if you ask me... LOL. A lot of people may not even know what "in
> band" and "out-of-band" even means. I grew up with X25, RS232, HDLC etc so
> that's ok by me. You have to be very very careful about how you explain
> things to  people. One of my favourite videos on YouTube is some guy asking
> Richard Feynman how magnets work...well, he did ask!
> https://www.youtube.com/watch?v=wMFPe-DwULM
>

I am just learning Haskell, having just finished working through _Learn You
a Haskell_, so I am no expert. However, the learning curve I am experience
reminds me of when I went from Applesoft BASIC to Pascal, and when I went
from C to C++. There was a lot of new terminology to learn such as
single-entry/single exit, procedures, formal and actual parameters,
encapsulation, polymorphism, early and late binding, and overloading.There
were plenty of nay-sayers that claimed that these paradigms introduced
unnecessary difficulties, but today you have to search far and wide for
someone who advocates GOTOs, and although O-O is not universally loved, it
is easily the dominant paradigm.

So, although I am still finding Haskell to be awkward for me, I am able to
wrestle with it until it clicks into place, and then it's really beautiful.
I feel like the benefits of the language will outweigh the effort it is
taking me to learn it.
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