system.expect

The expect module provides error checking functions for other libraries.

expect(index: number, value: any, ...: string): any

Check that a numbered argument matches the expected type(s). If the type doesn’t match, throw an error. This function supports custom types by checking the __name metaproperty.

Arguments

1. index: The index of the argument to check
2. value: The value to check
3. ...: The types to check for

Return Values

value

field(tbl: any, key: any, ...: string): any

Check that a key in a table matches the expected type(s). If the type doesn’t match, throw an error. This function supports custom types by checking the __name metaproperty.

Arguments

1. tbl: The table (or other indexable value) to search through
2. key: The key of the table to check
3. ...: The types to check for

Return Values

The indexed value in the table

range(num: number[, min: number = -math.huge][, max: number = math.huge]): number

Check that a number is between the specified minimum and maximum values. If the number is out of bounds, throw an error.

Arguments

1. num: The number to check
2. min: The minimum value of the number (inclusive) (defaults to -math.huge)
3. max: The maximum value of the number (inclusive) (defaults to math.huge)

Return Values

num