* Operators already in the ratcl starkit (mostly by Brian) *

* debugv - like 'do' but shows ops and intermediate results as subviews
* extend - add a column that is constructed from an expression on each row
* lag - adds a new column with a value from the given column in the previous row
* lead - adds a new column with a value from the given column in the next row
* ngroup - shorthand way of performing several levels of grouping at once
* oratcl - SQL query on oracle database is returned as a view.  Requires oratcl
* partition - Group, transform subview, then ungroup.
* pivot - returns a cross-tabulation of the given column names
* ratk - a Tk based view browser
* sqlite - SQL query on sqlite database is returned as a view.  Requires sqlite
* tostring - converts a column to string type
* vsplit - splits each cell of a given column into a subview (one row per list element)

* Steve's vops (until documented ask if you think they might be useful) *
* accum - accumulate values in a column
* datefmt - format a date column via Tcl's [[clock format]]
* fill - fill holes in a column with values from previous rows
* fillfrom - fill holes in a column with values from another column
* trimleft - trim string from left side of column values
* dupcol - duplicate a column
* vregsub - apply regsub to a column's values
* range - like slice but understands "end" + expressions like "end - 1"
* shape - returns column containing number of rows in specified subview