25.14 Filtering and deleting

Function: %string-filter char/char-set/pred str start past

Macro: string-filter S char/char-set/pred

Filter the selected substring, retaining only those characters that satisfy the char/char-set/pred argument:

• If it is a procedure, it is applied to the character as a predicate.
• If it is a character set, the character is tested for membership.
• If it is a character, it is used in an equality test.

Always return a newly allocated string.

Function: %string-delete char/char-set/pred str start past

Macro: string-delete S char/char-set/pred

Filter the selected substring, retaining only those characters that do not satisfy the char/char-set/pred argument:

• If it is a procedure, it is applied to the character as a predicate.
• If it is a character set, the character is tested for membership.
• If it is a character, it is used in an equality test.

Always return a newly allocated string.