ANSI Common Lisp 22 Printer 22.3 Formatted Output 22.3.8 FORMAT Miscellaneous Operations
220.127.116.11 Tilde Left-Paren: Case Conversion
The contained control string str is processed, and what it produces is subject to case conversion.
~:( capitalizes all words, as if by string-capitalize.
~@( capitalizes just the first word and forces the rest to lower case.
~:@( converts every lowercase character to the corresponding uppercase character.
In this example ~@( is used to cause the first word produced by ~@R to be capitalized:
(format nil "~@R ~(~@R~)" 14 14) "XIV xiv" (defun f (n) (format nil "~@(~R~) error~:P detected." n)) F (f 0) "Zero errors detected." (f 1) "One error detected." (f 23) "Twenty-three errors detected."
When case conversions appear nested, the outer conversion dominates, as illustrated in the following example:
(format nil "~@(how is ~:(BOB SMITH~)?~)") "How is bob smith?" NOT"How is Bob Smith?"