Fix Negative Float Type Data Parsing

[Alexius-Huang]

As described from PR #470, float parsing cases below are normal:

(3.14159265358979).to_d.to_s # => "3.14159265358979"
(-273.150000000).to_d.to_s # => "-273.15"

# and without the round bracket
3.14159265358979.to_d.to_s # => "3.14159265358979"

However, there is a case when a negative valued float type number cannot call method without round bracket

-273.150000000.to_d.to_s # ERROR

[st0012]

This issue blocks #379

[hachi8833]

I fixed the issue locally and would send the PR tomorrow. Wait a bit.

Before that, I'd create the following issue to close together after that:

• current compiler contains unused Incr = "++" and Decr = "--"
• handling positive sign: +1

---

Well, I found that Ruby treats +++++1 as 1, and --1 or ----1 as 1, and ---1 as -1.