[cvs-nhc98] patch applied (hat): Improvements to hat-explore.

[Malcolm Wallace]

Thu Feb  7 09:27:09 PST 2002  malcolm
  * Improvements to hat-explore.
    * Use a different low-level interface which gives correct parent
      information for identifiers, constructors, and literals.
    * In the state, store a stack of sub-expression contexts, not just
      expressions.  Thus, when you go backwards up the display, the cursor
      returns to the previously selected subexpression, not the whole line.

    A ./src/hattools/LowLevel.hs
    M ./src/hattools/Makefile -3 +3
    M ./src/hattools/SExp.hs -147 +143
    M ./src/hattools/utils.c -25 +493
    M ./src/hattools/utils.h -1 +2