Incorrect tokenization for negative constants

[jcoehoorn]

As first seen here:

https://3dprinting.stackexchange.com/questions/8534/why-is-2-2-2-equal-to-2-in-openscad-mathematical-order-of-operations

This expression:

 2 / -2 / 2 

results in -2. The expected result is -.5. You can see this with a new empty project with only this statement:

echo(2 / -2 / 2);

We believe what happens is the expression is evaluated right-to-left, where you first have 2 / 2 from the right side (resulting in 1), then the - operator is applied (now -1), and finally the leading division (2 / -1) becomes -2. Or perhaps it works left-to-right where the bug is the first / operator trying to resolve the right-hand side to an integer.

What should happen is the lexer should see the inner -2 as the same token, so you have a single literal -2 value hit the parser.

[t-paul]

Right, it seems the unary precedence is missing (e.g. like in this example). Same issue also with echo(2 / +2 / 2);