New returns a new formula for a given string.

Var returns a new variable that may be passed to a formula when evaluating it.

ErrInsufficientArgs is returned when a function in a formula requires more arguments than that provided.

ErrPanic is returned when a registered function panics.

ErrUnknownFunc is returned when a formula contains an unrecognized function.

ErrUnknownVariable is returned when a formula contains an unrecognized variable or constant.

Formula is a parsed formula that is ready to be evaluated.

Variable represents a variable with a specific name and value, that may be passed to a formula.