A cursor-oriented string library. Provides efficient string utilities for implementations with or without fast random-access strings.

The procedures below are similar to those in SRFI 13 or other string libraries, except instead of receiving and returning character indexes they use opaque string cursors. Returns true iff str is equal to the empty string "".Returns true iff check is true for any character in str. check can be a procedure, char (to test for char=? equivalence) or char-set (to test for char-set-contains?). Always returns false if str is empty.Returns true iff check is true for every character in str. check can be a procedure, char or char-set as in string-any. Always returns true if str is empty.Returns a cursor pointing to the first position from the left in string for which check is true. check can be a procedure, char or char-set as in string-any. The optional cursors start and end can specify a substring to search, and default to the whole string. Returns a cursor just past the end of str if no character matches.As above, ignoring the position and returning true iff any character matches.As string-find, but returns the position of the first character from the right of str. If no character matches, returns a string cursor pointing just before start.As string-find, but inverts the check, returning the position of the first character which doesn't match.As string-find-right, but inverts the check, returning the position of the first character which doesn't match. Concatenates the list-of-strings and return the result as a single string. If separator is provided it is inserted between each pair of strings.Split str into a list of substrings separated by pred, which defaults to #\space. Multiple adjacent characters which satisy pred will result in empty strings in the list. If the optional limit is provided, splits into at most that many substrings starting from the left.Returns a copy of the string str with all characters matching pred (default #\space) removed from the left.Returns a copy of the string str with all characters matching pred (default #\space) removed from the right.Returns a copy of the string str with all characters matching pred (default #\space) removed from both sides.Returns two values: the first cursors from the left in prefix and in str where the two strings don't match.Returns two values: the first cursors from the right in prefix and in str where the two strings don't match.Returns true iff prefix is a prefix of str.Returns true iff suffix is a suffix of str.The fundamental string iterator. Calls kons on each character of str and an accumulator, starting with knil. If multiple strings are provided, calls kons on the corresponding characters of all strings, with the accumulator as the final argument, and terminates when the shortest string runs out.Equivalent to string-fold, but iterates over str from right to left. Returns a new string composed of applying the procedure proc to every character in string. Apply proc to every character in str in order and discard the result. Count the number of characters in str for which check is true. Returns a cursor pointing to the first position in the string s1 where s2 occurs, or #f if there is no such match. Partial application of string-contains. Return a procedure of one argument, a string, which runs (string-contains str needle).Return a copy of string s with all 26 upper-case ASCII characters mapped to their corresponding 26 lower-case ASCII characters.Return a copy of string s with all 26 lower-case ASCII characters mapped to their corresponding 26 upper-case ASCII characters. Returns the substring of str between i (inclusive) and optional j (exclusive), which defaults to the end of the string. Returns the character of str at position i. Returns a string cursor pointing to the start of str. Returns a string cursor pointing just past the end of str. Returns a string cursor to the character in str just after the cursor i. Returns a string cursor to the character in str just before the cursor i. String cursor comparators.