3.4 Grade modifiers

Every grade modifier belongs to a grade modifier group. Each grade modifier group governs a single aspect of compilation. Because each modifier calls for handling that aspect differently from what the other modifiers in its group call for, a grade may contain at most one modifier from each group.

Note also that

• some grade modifiers are compatible only with some base grades (usually the ones that target C) and not others; and
• some grade modifiers in one group are incompatible not just with all other grade modifiers in the same group, but also with some grade modifiers from other groups.

Note also that the Mercury standard library will have been installed on your system in only a subset of the set of all possible grades.

Each of the following subsections except the last documents one group of grade modifiers. The last subsection documents which grade modifiers are compatible with grade modifiers from other groups.