String Type

The type String represents an immutable sequence of UTF-8 encoded bytes.

A String value is a fat pointer consisting of a pointer to the string data and the length in bytes.

String literals are stored in read-only memory and have static lifetime.

fn main() -> i32 {
    let s = "hello";
    0
}

String Literals

A string literal is a sequence of characters enclosed in double quotes (").

String literals support the following escape sequences:

An invalid escape sequence in a string literal is a compile-time error.

fn main() -> i32 {
    let a = "hello world";
    let b = "with \"quotes\"";
    let c = "with \\ backslash";
    let d = "line1\nline2";   // newline
    let e = "col1\tcol2";     // tab
    0
}

String Equality

Strings support the equality operators == and !=.

Two strings are equal if they have the same length and identical byte content.

fn main() -> i32 {
    let a = "hello";
    let b = "hello";
    let c = "world";
    if a == b && a != c {
        0
    } else {
        1
    }
}

String Ordering

Strings support the ordering operators <, <=, >, >=. Ordering uses lexicographic byte comparison.

String a is less than string b if at the first position where they differ, the byte in a is less than the byte in b, or if a is a prefix of b.

fn main() -> i32 {
    if "abc" < "abd" && "abc" <= "abc" && "b" > "a" && "abc" >= "abc" {
        0
    } else {
        1
    }
}

String Debugging

The @dbg intrinsic accepts a String argument and prints its content followed by a newline.

fn main() -> i32 {
    let msg = "Hello, world!";
    @dbg(msg);
    0
}

Limitations

The current implementation does not support:

• String indexing or slicing
• Pattern matching on strings

These features may be added in future versions. For mutable strings, concatenation, and search methods, see §3.10.