> import RegExpr.RegExprOperations

examples

> rA = L 'A'
> rAstar = Star rA
> rB = L 'B'
> rBstar = Star rB
> rAorBstar = Star (Choice rA rB)

Some sample runs (using intersectRE2, intersectRE won't terminate for interesting cases)

*RegExpIntersection> intersectRE2 rAstar rBstar
<((<>|<>)|<>)*,((<'A',{}>|<'B',{}>)|<>)>
*RegExpIntersection> eqRE Empty (intersectRE2 rAstar rBstar)
True
*RegExpIntersection> intersectRE2 rAorBstar rBstar
<((<>|<>)|<>)*,((<'A',{}>|<'B',<((<>|<'B',<>>)|<>)*,((<'A',{}>|<>)|<>)>>)|<>)>
*RegExpIntersection> eqRE rBstar (intersectRE2 rAorBstar rBstar)
True
*RegExpIntersection> intersectRE2 rAorBstar rAorBstar
<((<>|<>)|<>)*,((<'A',<((<'A',<>>|<'B',<>>)|<>)*,((<>|<>)|<>)>>|<'B',<((<'A',<>>|<'B',<>>)|<>)*,((<>|<>)|<>)>>)|<>)>
*RegExpIntersection> eqRE rAorBstar (intersectRE2 rAorBstar rAorBstar)
True
*RegExpIntersection> eqRE rAstar (intersectRE2 rAorBstar rAorBstar)
False
*RegExpIntersection> eqRE rBstar (intersectRE2 rAorBstar rAorBstar)
False

The regular expressions generated by the convert function are 'very verbose'.
There's space for lots of improvement.