Книга: Practical Common Lisp
The first category of special operators contains the three operators that provide basic control over the evaluation of forms. They're
PROGN, and I've discussed them all already. However, it's worth noting how each of these special operators provides one fundamental kind of control over the evaluation of one or more forms.
QUOTE prevents evaluation altogether and allows you to get at s-expressions as data.
IF provides the fundamental boolean choice operation from which all other conditional execution constructs can be built. And
PROGN provides the ability to sequence a number of forms.
- Controlling Newsreader Access
- 9.2.1 Getting the Evaluation
- 9.3.1 Getting the Evaluation
- Controlling Services at Boot with Administrative Tools
- Controlling Apache with Fedora's service Command
- Controlling Apache with Fedora's chkconfig Command
- Controlling Anonymous Access
- Controlling access to DNS servers outside the organization
- Controlling Access to UUCP Features
- The Basic Evaluation Rule
- 9.4.1 Getting the Evaluation