Fuzion • Library Modules • base • String • substring

String.substring

(from i32, to i32)

create substring of this string consisting of bytes from (inclusive) .. to (exclusive).

Precondition

pre
  debug: 0 ≤ from ≤ to ≤ String.this.byte_count
  debug: from=to || String.is_valid_utf8_first_byte utf8[from]
  debug: from=to || !String.is_multi_byte_start_byte utf8[to-1]

Postcondition

post
  debug 10 : result.codepoints_and_errors ∀ (.ok)

0.097dev (GIT hash 4fdfc3160d9df4641ee0c680b4f89bf1eb6d4133)

last changed: 2026-06-24