Crate to_be 

Simple truthy/falsy string evaluation for Rust — part of the cross-language to-be family.

to-be classifies strings commonly found in configuration and environment variables — such as "yes", "no", "true", and "off" — as truthy (recognised), truey (interpreted as true), or falsey (interpreted as false). Strings that are not recognised yield None from string_is_truthy and the Truthy::is_truthy trait method.

The library is implemented in several languages; to-be.Rust is the Rust port.

Terminology

• truthy — the string can be interpreted as having a boolean meaning;
• truey — the string is interpreted as true;
• falsey — the string is interpreted as false.

Note that string_is_falsey and string_is_truey answer narrower questions than string_is_truthy: an empty string is neither truey nor falsey, so both helper functions return false.

Installation

Reference in Cargo.toml in the usual way:

to-be = { version = "0" }

Components

Functions

• string_is_falsey — is the trimmed string a recognised falsey term;
• string_is_truey — is the trimmed string a recognised truey term;
• string_is_truthy — full three-way classification using stock terms;
• string_is_truthy_with — classification against custom Terms;
• stock_term_strings — obtain the built-in term tables as Terms;

Types

• Terms — selects stock or custom comparison strings;
• Truthy — trait providing is_truthy(), is_truey(), and is_falsey() on supported types;

Examples

use to_be::Truthy as _;

assert_eq!(Some(false), "no".is_truthy());
assert_eq!(Some(true), "True".is_truthy());
assert_eq!(None, "orange".is_truthy());

Further examples are provided in the repository examples directory and in the project README.

Enums

Terms

Directs custom truthyness behaviour.

Traits

Truthy

Trait that provides truthy attributes for an implementing type.

Functions

os_string_is_truthy

Indicates whether the given OS string is “truthy” and, if so, whether it is “truey” or “falsey”.

stock_term_strings

Obtain the stock term strings of the library.

string_is_falsey

Indicates that the given string, when trimmed, is deemed as “falsey”.

string_is_truey

Indicates that the given string, when trimmed, is deemed as “truey”.

string_is_truthy

Indicates whether the given string is “truthy” and, if so, whether it is “truey” or “falsey”.

string_is_truthy_with

Indicates whether the given string is “truthy” when evaluated against the given term strings.