[Haskell-cafe] Trapped by the Monads

Ketil Malde ketil+haskell at ii.uib.no
Wed Sep 21 06:51:49 EDT 2005

Bill Wood <william.wood3 at comcast.net> writes:

>> The variable mem is a so-called hybrid variable; it crunches
>> together 2 different concepts: a boolean value (could I allocate
>> memory?) and an address value (what is the address where I can find
>> my allocated memory).

IMO, Maybe is exactly the oppsite, it extends a data type with a NULL
value (to use DB terminology), and leaves no opportunity for confusing
the extended type with the original.

> I mostly agree with the "tightening-up", but there are times when I
> really miss the nil hacks :-)

In Haskell as well?  I alwasy felt the cost of inserting a "null"
predicate (when I want to test for an empty list) to be low.

If I haven't seen further, it is by standing in the footprints of giants

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