add column specify position

Hi all,

Is it possible to specify a position when adding a column to a table?

I want to swap one column for another without losing the column's
position. eg: given that 'foo' is the 5th column in an 8 column
table, I want to replace it with a 'bar' column at column 5.

ALTER TABLE qwe DROP COLUMN foo;
ALTER TABLE qwe ADD COLUMN bar;

I'm writing a sql script to migrate from one version of my schema to
another, dropping one column and adding another to a number of
tables. Unfortunately, the windowing toolkit I'm using relies on
integer values to determine column positions.

Any ideas come to mind?

Thanks in advance!
Scott