[cvs-nhc98] patch applied (hat): Partial fix for a hat-observe pattern involving infix constructors.

[Malcolm Wallace]

Wed May 24 05:54:18 PDT 2006  malcolm
  * Partial fix for a hat-observe pattern involving infix constructors.
  Chained constructors like (_ :- _ :+ _ :* _) previously matched only on
  the first constructor (giving lots of false positives).  Now the
  constructors are treated as left assocative, with equal precedence,
  which does the right thing for normal lists at least.  (A full solution
  using known fixities from the trace file would be hugely more complex.)

    M ./src/hattools/Pattern.hs -4 +7