Brent Yorgey wrote:
On Sun, May 31, 2009 at 05:42:44PM +0200, Daniel Fischer wrote:
But that has nothing to do with the phenomenon, in the inferred type signatures of safeSecond and tidySecond, the 'a' resp. 't' are both type variables of kind *. The only difference is that in one case the name supply delivered 'a' and in the other it delivered 't'.
I think one source of difference is that ghci tries to maintain type variable names from declared type signatures. So perhaps one of the library functions used to define 'safeSecond' has an explicitly declared type signature that mentions 'a', and a library function used to defined 'tidySecond' has one that mentions 't'.
This sounds like a good answer. Thanks! I tried this: safe xs = head xs has inferred type safe :: [a] -> a tidy (x:_) = x has inferred type tidy :: [t] -> t I can rest easy now, and get on to the next exercise. Best Ivan -- ============================================================ Ivan A. Uemlianin Speech Technology Research and Development ivan@llaisdy.com www.llaisdy.com llaisdy.wordpress.com www.linkedin.com/in/ivanuemlianin "Froh, froh! Wie seine Sonnen, seine Sonnen fliegen" (Schiller, Beethoven) ============================================================