Singular Manual: No rvalue of increments and assignments

| ### 6.3.1 No rvalue of increments and assignments The increment operator `++` (resp. decrement operator `--`) has no rvalue, i.e., cannot be used on the right-hand sides of assignments. So, instead of
    j = i++;  // WRONG!!!
(which results in an error), it must be written
    i++; j = i;
Likewise, an assignment expression does not have a result. Therefore, compound assignments like `i = j = k;` are not allowed and result in an error.

User manual for Singular version 4-1-3p2, 2020, generated by texi2html.