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24.1.2.1 Feature Expressions
  
Boolean combinations of features, called feature expressions, are used by the #+ and #- reader macros in order to direct conditional reading of expressions by the Lisp reader. 
The rules for interpreting a feature expression are as follows: 
- feature  
- 
If a symbol naming a feature is used as a feature expression, the feature expression succeeds if that feature is present; otherwise it fails. 
 
- (not feature-conditional)  
- 
A not feature expression succeeds if its argument feature-conditional fails; otherwise, it succeeds. 
 
- (and feature-conditional*)  
- 
An and feature expression succeeds if all of its argument feature-conditionals succeed; otherwise, it fails. 
 
- (or feature-conditional*)  
- 
An or feature expression succeeds if any of its argument feature-conditionals succeed; otherwise, it fails. 
 
 
24.1.2.1.1 Examples of Feature Expressions
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