Strings

Vex uses two string-facing types in normal code:

• str: a borrowed string view
• string: an owned string value

Both are available from the prelude. You do not need an import.

str vs string

Use str when you only need to read text. Use string when you need to return, store, concatenate, or otherwise own the result.

fn greet(name: str): string {
	return "Hello, " + name;
}

fn main(): i32 {
	let label: str = "vex";
	let message: string = greet(label);
	println(message);
	return 0;
}

In current Vex docs, prefer the lowercase spelling string. Some older tests in the repository still use String while naming is being normalized.

Literals and cheap reads

String literals are the easiest way to produce text:

let site = "vex.dev";
let prefix = "https://";
let full = prefix + site;

Common read-only operations are available directly on string values used throughout the repo:

let url = "https://example.com/api/v1/users";

let ok_prefix = url.starts_with("https://");
let ok_suffix = url.ends_with("users");
let has_api = url.contains("/api/");
let idx = url.indexOf("example");

Conversions and formatting

Vex code typically converts non-string values with .toString():

let count = 42;
let line = "count=" + count.toString();
println(line);

That pattern is used broadly in the examples and standard library tests.

Common operations

Concatenation

The + operator is the most common way to build new owned strings:

let part1 = "Hello, ";
let part2 = "World!";
let combined = part1 + part2;

Search

let haystack = "Lorem ipsum dolor sit amet";

let found = haystack.contains("amet");
let pos = haystack.indexOf("ipsum");

Trimming and case conversion

let padded = "    hello world    ";
let trimmed = padded.trim();
let upper = trimmed.toUpper();
let lower = upper.toLower();

Repeat

let token: string = "ab";
let repeated = token.repeat(4);

Ownership guidance

• Accept str in APIs that only inspect text.
• Return string when you create a fresh value.
• Use concatenation and .toString() for straightforward text building.
• Reach for template literals when you need multi-line structured output.

Internal model

Vex's owned string uses the compact omni-string layout described in the language internals. The important user-facing fact is simpler: short strings stay cheap, and the language keeps common string operations ergonomic.

See also

• Template Literals
• Vec<T>
• FFI