Crate rant

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Rant is a high-level procedural templating language. It is designed to help you write more dynamic and expressive templates, dialogue, stories, names, test data, and much more.

For language documentation, see the Rant Reference.

The Rant context

All programs are run through a Rant context, represented by the Rant struct. It allows you to execute Rant programs, define and retrieve global variables, manipulate the RNG, and compile Rant code.

Reading compiler errors

You will notice that the Err variant of the Rant::compile* methods is () instead of providing an error list. Instead, errors and warnings are reported via implementors of the Reporter trait, which allows the user to control what happens to messages emitted by the compiler. Currently, Rant has two built-in Reporter implementations: the unit type (), and Vec<CompilerMessage>. You can also make your own custom reporters to suit your specific needs.




Represents an error that occurred when attempting to load a Rant module.

A Rant execution context.

Rant’s “empty” value.

A function callable from Rant.

Represents Rant’s list type, which stores an ordered collection of values.

Represents Rant’s map type, which stores a collection of key-value pairs. Map keys are always strings.

Provides options for customizing the creation of a Rant instance.

A compiled Rant program.

Contains metadata used to identify a loaded program.

Represents Rant’s string type.


Error produced by indexing a RantValue.

Error produced by keying a RantValue.

Represents the reason for which a Rant module failed to load.

Defines endpoint variants for Rant functions.

Represents Rant’s special type, which stores internal runtime data.

A dynamically-typed Rant value.

A lightweight representation of a Rant value’s type.

Represents a Rant variable of one of two flavors: by-value or by-reference.

Error produced by slicing a RantValue.

Error produced by a RantValue operator or conversion.


The build version according to the crate metadata at the time of compiling.

The default name given to programs compiled from raw strings.

The name of the environment variable that Rant checks when checking the global modules path.

The file extension that Rant expects modules to have.

The Rant language version implemented by this library.


Trait for converting something to a Rant function.

Enables conversion from a RantValue to a native type.

Converts from argument list to tuple of impl FromRant values

Enables conversion from a native type to a RantValue.

Type Definitions

Type alias for Rc<RantFunction>

Type alias for Rc<RefCell<RantList>>

Type alias for Rc<RefCell<RantMap>>

The result type used by Rant value index read operations.

The result type used by Rant value index write operations.

The result type used by Rant value key read operations.

The result type used by Rant value key write operations.

The result type used by Rant value operators and conversion.

The result type used by Rant value slice read operations.

The result type used by Rant value slice write operations.