22.3.8.1 Tilde Left-Paren: Case Conversion

~(str~)

The contained control string str is processed, and what it produces is subject to case conversion.

With no flags, every uppercase character is converted to the corresponding lowercase character.

~:( 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?"