— Scheme Procedure: string-copy str [start [end]]

Return a freshly allocated copy of the string str. If given, start and end delimit the portion of str which is copied.

— Scheme Procedure: substring/shared str start [end]

Like substring, but the result may share memory with the argument str.

— Scheme Procedure: string-copy! target tstart s [start [end]]

Copy the sequence of characters from index range [start, end) in string s to string target, beginning at index tstart. The characters are copied left-to-right or right-to-left as needed – the copy is guaranteed to work, even if target and s are the same string. It is an error if the copy operation runs off the end of the target string.

— Scheme Procedure: string-take s n
— Scheme Procedure: string-take-right s n

Return the n first characters of s.

— Scheme Procedure: string-drop s n
— Scheme Procedure: string-drop-right s n

Return all but the first n characters of s.

— Scheme Procedure: string-pad s len [chr [start [end]]]
— Scheme Procedure: string-pad-right s len [chr [start [end]]]

Take characters from start to end from the string s and return a new string, right-padded by the character chr to length len. If the resulting string is longer than len, it is truncated on the right.

— Scheme Procedure: string-trim s [char_pred [start [end]]]
— Scheme Procedure: string-trim-right s [char_pred [start [end]]]
— Scheme Procedure: string-trim-both s [char_pred [start [end]]]

Trim s by skipping over all characters on the left that satisfy the parameter char_pred:

• if it is the character ch, characters equal to ch are trimmed,
• if it is a procedure pred characters that satisfy pred are trimmed,
• if it is a character set, characters in that set are trimmed.

If called without a char_pred argument, all whitespace is trimmed.