sympy/sympy — pull request #1440 by scolobb (2012-07-24 19:30:48+00:00)
Title: Fix long arrows in Unicode pretty printing.

Previously those classes were pretty printed using long Unicode symbols,
which worked erratically on different terminals. This commit uses more
standard characters.

Things are now printed like this:

```
{g∘f:A₁——▶C₁: ∅, id:A₁——▶A₁: ∅, id:B——▶B: ∅, id:C₁——▶C₁: ∅, f:A₁——▶B: ∅, g:B——▶C₁: ∅}
══▶ {g∘f:A₁——▶C₁: {unique}}

```

Thanks to @asmeurer for the suggestion!