std.assert

The assertion module. The most commonly used tool in tests and examples.

use std.assert

Function Overview

Function	Signature
assert	(cond: Bool, ?msg: String) -> Void

Functions

assert

assert: (cond: Bool, ?msg: String) -> Void

Asserts that cond is true.

• cond — Boolean expression to be evaluated
• msg — Optional message, ? indicates it can be omitted; output together with the diagnostic when the condition does not hold

Returns: returns Void when the condition holds, without interrupting execution. Errors: throws E6005 (assertion failure) when the condition is false, and the program exits with a non-zero code.

use std.assert

main: () -> Void = {
    assert(1 > 0)
    assert(1 > 0, "this literal assertion must hold")
}

Assertions are the primary means of judgment for test corpora — both src/std/tests/*.yx and tests/yaoxiang/** work in a way that an assert failure causes the process to report an error:

use std.assert
use std.list

main: () -> Void = {
    list.len([1, 2, 3]) == 3
    assert(list.len([1, 2, 3]) == 3, "len == 3")
}

Related

• Test Specification — Corpus organization and judgment conventions
• Error Code Reference — E6005 assertion failure