[Haskell-cafe] state and exception or types again...

[Bulat Ziganshin]

Hello Andrea,

Thursday, August 31, 2006, 4:22:49 PM, you wrote:

> The tutorial will have this outline: first we build a monad adding
> output, exception, and state. Then we use monad transformer to take
> out state and output and add debug, doing lifting, put(ing) and
> get(ing) by hand, to understand the central role of type
> matching/construction.

imho, your tutorial makes the error that is a very typical: when you
write your tutorial you already know what are monads and what the
program you will construct at the end. but your reader don't know all these!
for such fresh reader this looks as you made some strange steps, write
some ugly code and he don't have chances to understand that this ugly
code is written just to show that this can be simplified using monads.
i've tried to read it imaging myself as fresh reader and was stopped
at some middle because code was too complicated to understand and
it was completely imobvious (for fresh reader) that we just wrote
"innards" of monad and then will reduce all this ugly code just to
">>=" calls


-- 
Best regards,
 Bulat                            mailto:Bulat.Ziganshin at gmail.com