Negative operator isn't working

[JoePelz]

All of the following compile to invalid C code.

a = -1
b = -1.0
c = 13 + -5

Specifically,

a = 1
b = 2
c = a + -b

becomes

int a;
a = 13; 
int b;
b = 17; 
Integer_assign((c + (a - b)));

in which Integer_assign is an undefined reference and c is an undeclared identifier

The negative operator should work as it does in C.