Positive decimal number command arguments can't start with a point

The bug

In commands that accept fractional numbers (floats), positive numbers are not allowed to start with a decimal point, such as .1. Negative numbers like -.1 work just fine.

How to reproduce

1. /tp @s -.1 -.1 -.1

2. /tp @s .1 .1 .1

Expected results

Both commands should work

Observed results

Second command is a syntax error