API

str mirrors the native String surface, grouped here by what each operation returns.

• Slicing & Trimming — ops that return a view: slice, substring, substr, charAt, at, trim / trimStart / trimEnd / trimLeft / trimRight, split.
• Searching — queries that return a primitive: indexOf, lastIndexOf, includes, startsWith, endsWith (each accepting a stringor a str needle).
• Transforming — ops that return an owned string: concat, repeat, padStart, padEnd, replace, replaceAll, toUpperCase, toLowerCase.
• Comparison & Operators — equals, equalsString, compareTo, localeCompare, and the == / != / < / <= / > / >= / + / [] operators.
• Encoding — str.UTF8 / str.UTF16, plus the static constructors and MAX_LENGTH.

Conventions

Each operation exists in two forms (see The View Model):

v.slice(2, 5); // instance method on a view
str.slice(s, 2, 5); // free function — `s` is a string or a view

• Returns a view → another str, no bytes copied.
• Returns a primitive → i32 / bool, no allocation.
• Returns a string → an owned string, allocated once.

Indices are UTF-16 code units, and out-of-range / negative arguments behave exactly as the matching native String method (verified by differential fuzzing). Convert a string into a view with str.from(s).