Signature: substring(s: string, start: int, end: int) -> Result<string, StringError>

Description: Extracts s[start, end). Returns Error(IndexOutOfRange) if start<0, end>len, or start>end.

Parameters

• s (string): The source string
• start (int): Starting index (inclusive)
• end (int): Ending index (exclusive)

Returns: Result<string, StringError>

Example

substring("hello", 1, 4)  // Success { value: "ell" }