sympy/sympy — pull request #1484 by jrioux (2012-08-14 11:42:33+00:00)
Title: Implement integral of Piecewise with symbolic conditions.

In this pull request:

* Handle symbolic delimiters in conditions to Piecewise. For example,
```
>>> L = Symbol('L', positive=True)
>>> p = Piecewise((1, And(-L <= x, x <= L)), (0, True))
>>> integrate(p, (x, -oo, oo))
2*L
```

* Handle Or() conditions, e.g. Or(x < -1, x > 1)

* If two subsequent ExprCondPairs in Piecewise have the same expression, reduce them to one ExprCondPair with corresponding Or condition. e.g., automatically canonalize
```
Piecewise((e, c1), (e, c2))
```
to
```
Piecewise((e, Or(c1, c2)))
```

* Tests