Henning Thielemann wrote:
Data Orientation = Row | Column
Data Vector a = Vector Orientation [a]
In the first mail you wrote
"9. There are row vectors and column vectors, and these are different
types. You get type errors if you mix them incorrectly."
I interpreted that you want to encode the information Row or Column into
the type. This sounds reasonable to me because multiplying e.g. a column
vector by a matrix is so obviously wrong that it should be detected
statically.
Sorry, I should have been more precise, I used too straightforward an
encoding from Maple (which is dynamically typed) into Haskell. I should
have used the usual type-trickery to encode the Orientation as 2
different types, to have ``types reflect values''.
Jacques
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