1999-02-19  Miguel de Icaza  <miguel@nuclecu.unam.mx>

	* src/clipboard.c (paste_cell): Do not render the value if the
	result is an error.

	* src/cell.c (cell_copy): Do not copy the value of a cell when the
	value is NULL (due to the cell having an error).

	* src/expr.c (eval_expr): Evaluate binary operations in parts to
	keep the correct error message on an operation if possible.
	(eval_expr): Propagate errors.

	* src/item-edit.c (item_edit_draw): Sync the before-cursor and
	after-cursor Y-display text cordinate.

	* src/expr.c (eval_funcall): Add type checking for the simple
	functions.

	* doc/C/Makefile.am (install-data-local): use topsrcdir here (fix
	from Ian Campbell <ijc25@cam.ac.uk>

	* src/fn-math.c (gnumeric_not): Implement NOT.