Advises the compiler that each quality should be given attention according to the specified corresponding value. Each quality must be a symbol naming an optimize quality; the names and meanings of the standard optimize qualities are shown below.
|compilation-speed||speed of the compilation process|
|debug||ease of debugging|
|safety||run-time error checking|
|space||both code size and run-time space|
|speed||speed of the object code|
0 means that the corresponding quality is totally unimportant, and
3 that the quality is extremely important;
2 are intermediate values, with
1 the neutral value.
(quality 3) can be abbreviated to quality.
The consequences are unspecified if a quality appears more than once with different values.