Fix T74552: Distribute negatives in number input

This applies a relatively simple solution for fixing some unintuitive
cases in unit handling.

Currently entering -1m50cm evaluates to -0.5m, and similarly 1'6"
evaulates to just half a foot. So effectively there's an implied + just
between the numbers, which is quite confusing.

This works by adding parentheses so the negative distributes to the
block of values before the next operator.

For example:
|         Before         |           After            |
| `-1m50cm + 1m -2m50cm` | `-(1m50cm) + 1m -(2m50cm)` |
|   `-4m + 0.5 / -1.1`   |   `-(4m) + 0.5 / -(1.1)`   |
|         `-1'6"`        |         `-(1'6")`          |
|        `-1e-2cm`       |        `-(1e-2cm) `        |

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D7813

0 files changed, 0 insertions, 0 deletions